Re: [M100] M100 repair video

[Fugu ME100]

 Very nice job.  I have not had a xtal failure that was interesting.

Would be good to have a video on repairing the LCD screen, that is one where I 
have the  most problems.  Also perhaps a one to deal with keyboard issues?

Looking forward to the next one.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Josh Malone mailto:josh.mal...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Wednesday, January 29, 2020 at 6:34 PM
To: Model 100 Discussion 
mailto:m100@lists.bitchin100.com>>
Subject: [M100] M100 repair video

All,

I finally made my first M100 repair video. This was a repair job that I picked 
up at Tandy Assembly -- one of several, actually. This may also be my first 
one-sitting fix (turned out to be a simple problem).

https://www.youtube.com/watch?v=PSD01xLqwEc

I'm still planning to make more videos of my repair jobs. I tried to include 
stuff that I thought might help others with their troubleshooting.

-Josh

Re: [M100] M100 repair video

[Fugu ME100]

I have been using a ketchup/condiment bottle as an alcohol dispenser :)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Kevin Becker mailto:ke...@kevinbecker.org>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Wednesday, January 29, 2020 at 7:20 PM
To: mailto:m100@lists.bitchin100.com>>
Subject: Re: [M100] M100 repair video

That alcohol dispenser looks really handy.


On Wed, 2020-01-29 at 21:34 -0500, Josh Malone wrote:
All,

I finally made my first M100 repair video. This was a repair job that I picked 
up at Tandy Assembly -- one of several, actually. This may also be my first 
one-sitting fix (turned out to be a simple problem).

https://www.youtube.com/watch?v=PSD01xLqwEc

I'm still planning to make more videos of my repair jobs. I tried to include 
stuff that I thought might help others with their troubleshooting.

-Josh

Re: [M100] DIY REX quandry

[Fugu ME100]

Yes mixed up my sizes 102 vs 100.

Not sure I suspect they are so close that with flexible pins you would not 
notice.

I know I have two different '80s 3rd party modules sizes they were hard to swap 
around when I was testing.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Brian White mailto:b.kenyo...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 26, 2020 at 5:57 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] DIY REX quandry

M10 ram is a 0.75" module, so maybe .75 and .7 ?

How could they change the M100 socket size without offering some new catalog 
number for ram modules that fit it?

T102 has .6 chips with no module just a standard 0.6 dip28 package.

Then 200 is .75 again.

Re: [M100] DIY REX quandry

[Fugu ME100]

Yes, at least on the M100s I have upgraded.  There seems to be a 650mil and 
600mil version of the RAM socket width.  I think the 650 is on the older 
boards.  Later it appears to have become 600mil – the standard size.  They are 
so close that it is not really noticeable.  I only ‘discovered’ it when 
swapping around RAM modules and then building my own version

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 26, 2020 at 4:44 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] DIY REX quandry


2 different socket sizes?

Re: [M100] DIY REX quandry

[Fugu ME100]

Yes at least two snips unfortunately. They are really designed for SIL modules 
with a packaging machine to place the pins.

The way I normally work is to cut off one sides worth of pins from the roll, 
then snip off the bottom runner with a pair of tin snips, trying to keep the 
pins the same length. The top runner I leave on. Insert a set of pins through 
each side of the module and into a donor IC socket to get both sides lined up 
and hold the unit together for the next step.  Solder the underside of the 
module to tack in the pins.  Once done break off the top runner and snip off 
the extended pin top close to the board.  To make a neater job touch solder the 
cut pin tops.  You can then trim the pins if needed.  The pins should be 
aligned and ready to insert into the IC socket.

I have used them on M100 RAM modules and they bend enough to deal with the two 
different socket sizes on the M100 boards.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 26, 2020 at 3:30 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] DIY REX quandry

thanks, great tip.  I hadn't thought about damage to the socket.
How do you actually accomplish this?
Seems that you need to do 2 snips per pin.

In the drawing each end of the pin is connected to a frame.



On Sun, Jan 26, 2020 at 3:19 PM Fugu ME100 
mailto:b4me...@hotmail.com>> wrote:
I have good experience using TE Connectivity AMP Connectors 1544210-2 (Digikey 
A117856CT-ND or Mouser 571-1544210-2) on RAM modules or other boards that are 
to be plugged into a socket.  Use an old IC socket to align the strip and 
solder, then snip off the top part makes for a very neat final look.  The pins 
are flat so they do not damage the socket.

I agree the round or square pins in my experience tend damage/deform sockets 
making them useless for other plug ins.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Mike Stein mailto:mhs.st...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 26, 2020 at 12:05 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] DIY REX quandry

Re: [M100] REXCPM & M100 CP/M

[Fugu ME100]

Will it be able to use a DVI for screen output?

On 25/1/20, 8:39 PM, "M100 on behalf of Philip Avery"
 wrote:

>That will work with M100 CP/M. Same CP/M command (Stat) will redirect
>'screen' output to the printer port if you like.
>In fact you can redirect keyboard input from the serial as well, so you
>can just use the M100 as a processor if you want.
>
>Philip
>
>
>>
>>
>

Re: [M100] DIY REX quandry

[Fugu ME100]

I have good experience using TE Connectivity AMP Connectors 1544210-2 (Digikey 
A117856CT-ND or Mouser 571-1544210-2) on RAM modules or other boards that are 
to be plugged into a socket.  Use an old IC socket to align the strip and 
solder, then snip off the top part makes for a very neat final look.  The pins 
are flat so they do not damage the socket.

I agree the round or square pins in my experience tend damage/deform sockets 
making them useless for other plug ins.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Mike Stein mailto:mhs.st...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 26, 2020 at 12:05 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] DIY REX quandry

Re: [M100] Request for info on RS DV Interface

[Fugu ME100]

I have no experience with the DVI drives, but having replaced quite a few caps 
on model T boards over the years it should be one of the first tasks to keep 
the drives happy.  The description in the link sounds very familiar especially 
looking for damaged tracks under and around the caps. Rebuilt correctly it 
will not hurt the drive and might avoid hours of future frustration trying to 
maintain the DVI and its drives.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Charles Hudson mailto:clh...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, January 20, 2020 at 6:07 AM
To: mailto:m100@lists.bitchin100.com>>
Subject: [M100] Request for info on RS DV Interface



I'm just wondering if the community has experience with this problem and can 
shed light on the subject.  If it has to be I'll do it, just a question of 
priority.

Re: [M100] Request for info on RS DV Interface

[Fugu ME100]

Probably the easiest and safest :) method is to use an Auto-transformer to step 
down the UK 240V to the US 120V.  They should be available with a UK plug on 
one side and a US socket on the other you can then simply plug in the DVI unit 
without touching any live 240V mains - they are generally packaged for 
immediate use no need to wire up.  The DVI unit takes 66W (according to the 
manual) just make sure the Auto–transformer is capable of supplying more than 
that I would look for something  >100W.  The only issue is that the 120V will 
be at 50Hz and not 60Hz which will make the internal DVI transformer less 
efficient but it should be OK.

https://uk.rs-online.com/web/p/autotransformers/3101156/ this one might be a 
good option to look at, there are quite a few others, the higher VA the better 
- depends on your budget.

The other issue will be the composite video output might/will need an adapter 
too in order to convert it to the UK PAL standard, it will be NTSC Composite 
output in the US version.  They are available on the well known online auction 
sites or other online retailers.  Some of them claim to convert to HDMI 
although not sure how good the quality will be from those units.   If you have 
a composite video monitor that should produce the best results.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of mailto:james.z...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 19, 2020 at 6:32 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Request for info on RS DV Interface

I’ve never done anything like that, so if anyone can give a little hand 
holding, then sure!

I’m fine soldering, it’s just I haven’t played around with power supplies. Once 
zapped myself with 240v mains while working on a Macintosh Plus, once was quite 
enough. Sitting in a house In the dark, because the fuse box was tripped, with 
my arm killing me., ah the memories :-P

Re: [M100] Request for info on RS DV Interface

[Fugu ME100]

If you wanted to retain the look/feel you could replace the 120V step down 
transformer wth a 240V step down.  The DVI Service manual does not mention the 
step down voltage but it might be on the transformer.  You would also have to 
replace the AC wiring, switch and fuse holder with 240V rated cables, as well 
as the fuse.  From the service manual that is all R/S swapped when producing 
the UK version (apart from the RF modulator for the TV of course :) ).  The 
power supply board is the same – or at least it appears to be from the parts 
list.


The service manual is on http://www.classiccmp.org/cini/systems.htm in the M100 
section.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Mike Stein mailto:mhs.st...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, January 18, 2020 at 3:55 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Request for info on RS DV Interface

Looks like a garden variety linear 12 and 5 V supply; a 3 Amp each switcher 
should be able to replace it.
- Original Message -
From: James Zeun
To: m...@bitchin100.com
Sent: Saturday, January 18, 2020 6:22 PM
Subject: Re: [M100] Request for info on RS DV Interface



If I didn't want to use a step down. Would it take much to replace the internal 
PSU with something else?

Re: [M100] Club100 Personal Libraries Working again

[Fugu ME100]

Thanks!  Great to have them back.

Preview would be nice to get working again, or just working :-)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 12, 2020 at 11:11 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Club100 Personal Libraries Working again

thanks Ken!

On Sun, Jan 12, 2020 at 2:10 PM Ken Pettit 
mailto:petti...@gmail.com>> wrote:
All,

I updated the Personal Libraries PHP code this morning to work with PHP
7.  Things seems to be working as much as I could test them.  I can
navigate, download files, upload, delete, etc.

If I can get to it, I will also try to get file preview function working
again (it hasn't worked for a long time for some reason).

Please post any bugs you see.

Thanks,
Ken

Re: [M100] Issue with sd2tpdd

[Fugu ME100]

Just tried the dice program and it loaded and saved without problems.  It did 
have a syntax error in line 1020 :)

This was using the REX vanilla TSDOS ROM version with an ATMEGA "TPDD Drive", 
however it was not using SD2TPDD.  It was using a heavily modified variant of 
DLPLUS running on a MEGA platform, it is not an Arduino board.  The file was 
only one directory level down though.  File size is 2379 as reported.

Also tried the MENU.BA program from the link Brian provided and that saved and 
loaded fine  - although it did need a reset of the machine after it was run. :)

I think REX TS-DOS appears to be working OK?

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Gary Hammond mailto:ghamm...@hotmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Tuesday, October 15, 2019 at 1:22 PM
To: "m...@bitchin100.com" 
mailto:m...@bitchin100.com>>
Subject: Re: [M100] Issue with sd2tpdd

Observations from the comments to date and other questions:

  *   The first 2 bytes corruption may not affect all files. (Does the file 
size matter?)
  *   Brian’s testing seems to indicate that the issue isn’t restricted to 
SD2TPDD.
  *   I tried Dans suggestion of adding the ‘break’ around line 191. It has not 
solved the trailing null problem.
  *   I have noticed references to DOS100.CO in the comments and on GitHub. 
Under what circumstances does it need to be there?
  *   How can we check that we are using the same version of TS-DOS?
  *   Is capitalisation of the filename important on the SD card?
  *   Is file size important, i.e., does the final packet of file data sent 
have to be a particular size or power of 2 or buffer rollover point to trigger 
this?
  *   Is it possible that there is also a bug in TS-DOS?

More details of my configuration:

  *   The file I am using is 2 levels down on the SD card i.e., zz -> games 
-> dice2.do
  *   The file is 2379 bytes long.
  *   The M100 has a REX fitted with TS-DOS ROM loaded.

The file I have been using follows…

1 ' Dice Program 
2 'Dice rolling program for Model 100,102,200
3 'Gary Hammond 2016
4 'ghamm...@hotmail.com
10 '*** Initialisation ***
30 DIM DR(5) ' Dice roll
40 PP=41 ' Print Position
50 DT$="*"   ' Dice dot symbol
100 '*** Main Program ***
110 GOSUB 200 'Get the number of die to roll
120 GOSUB 1000 'Randomise the random number
130 CLS
140 PRINT@292,"Roll or Quit (R/Q)?";
150 GOSUB 300 'Wait for roll/quit command
150 IF AN = 1 THEN GOSUB 400 ELSE GOTO 170 'Either roll the dice or quit
160 GOTO 140
170 CLS
180 PRINT"Goodbye!"
199 END
200 '*** Get the number of die to roll ***
210 CLS
220 PRINT@285,"How many die to roll (1-4)";
230 A$ = INKEY$
240 IF A$ = "1" OR A$ = "2" OR A$ = "3" OR A$ = "4" THEN 260
250 GOTO 230
260 DN = VAL(A$)
299 RETURN
300 '*** Wait for roll/quit command ***
310 A$ = INKEY$
320 IF A$ = "" THEN 310
330 IF A$ = "R" OR A$ = "r" OR A$ = " " THEN AN = 1:RETURN
340 IF A$ = "Q" OR A$ = "q" THEN AN = 0:RETURN
350 GOTO 310
399 RETURN
400 '*** Roll the dice 
410 CLS:PP=41 ' Print position for die
420 FOR RN = 1 TO DN
430   Y = RND(1)
440   LET Z=(RND(Y)*6+1)
450   LET DR(RN)=INT(Z)
460   GOSUB 500 'Draw the dice
470   PP = PP + 10
480 NEXT RN
499 RETURN
500 '*** Draw the dice ***
510 PRINT@PP,CHR$(235)+STRING$(5,231)+CHR$(236)
520 FOR X = 1 TO 3
530   PRINT@PP+(40*X),CHR$(233)+STRING$(5," ")+CHR$(234)
540 NEXT X
550 PRINT@PP+160,CHR$(237)+STRING$(5,232)+CHR$(238)
560 ON DR(RN) GOSUB 650,700,750,800,850,900
570 RETURN
650 '*** Draw the 1 dice face ***
660 PRINT@PP+83,DT$
670 RETURN
700 '*** Draw the 2 dice face ***
710 PRINT@PP+44,DT$
720 '
730 PRINT@PP+122,DT$
740 RETURN
750 '*** Draw the 3 dice face ***
760 PRINT@PP+44,DT$
770 PRINT@PP+83,DT$
780 PRINT@PP+122,DT$
790 RETURN
800 '*** Draw the 4 dice face ***
810 PRINT@PP+42,DT$+" "+DT$
820 '
830 PRINT@PP+122,DT$+" "+DT$
840 RETURN
850 '*** Draw the 5 dice face ***
860 PRINT@PP+42,DT$+" "+DT$
870 PRINT@PP+83,DT$
880 PRINT@PP+122,DT$+" "+DT$
890 RETURN
900 '*** Draw the 6 dice face ***
910 PRINT@PP+42,DT$+" "+DT$
920 PRINT@PP+82,DT$+" "+DT$
930 PRINT@PP+122,DT$+" "+DT$
940 RETURN
1000 REM  RANDONMISE THE RANDOM VALUE 
1010 TS = VAL(RIGHT$(TIME$,2))
1020 TM = VAL(MID$(TIME$(4,2))
1030 FOR N = 1 TO (TM * TS) + 13
1040   Y = RND(1)
1050 NEXT N
1060 RETURN

Re: [M100] Issue with sd2tpdd

[Fugu ME100]

I would probably just use memset rather than the for loop. :)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Dan Higdon mailto:therealh...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Tuesday, October 15, 2019 at 8:10 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Issue with sd2tpdd

I'd also consider re-writing clear buffer to take a (char *c) parameter, like 
this:

void clearBuffer(char* buffer, int bufferSize){ //Fills the buffer with 0x00
  for(int i=0; i

Re: [M100] Issue with sd2tpdd

[Fugu ME100]

This is normal behavior it is the 00H - Directory Reference message,
requesting the first directory block and subsequent blocks. The byte after
the attribute specifies the type.  I agree it does look weird when you see
it happening.  

Do you happen to have a link to the MENU.BA file I would like to try the
exercise see if the results are the same, thnx.  However first I need to
fix my M100 it now has a clock problem when I powered it up this morning,
it was working yesterday :)



On 15/10/19, 3:28 AM, "M100 on behalf of Brian K. White"
 wrote:

>There does seem to be something weird with SD2TPDD though (at least my
>hacked-up version).
>If I enable debugging to the serial console, reading a file from SD to
>M100 generates traffic that looks questionable.
>There's a packet that repeats a bunch of times that looks like it has
>the filename minus the first letter. No idea what that's about. Almost
>looks like it's doing that operation wrong, and TS-DOS is retrying a
>bunch of times before giving up.
>The reverse operation, writing the same file from M100 to SD, generated
>far fewer packets, and didn't have any packets that looked like missing
>the first letter of the filename.

Re: [M100] M100 only displays black blocks

[Fugu ME100]

Must be the fall seasonŠ..

My M100 just did the same thing while in use on A/C power, the picture
looks almost identical apart from the white block and it only has two
bands. 

The NiCd has been replaced and a cold reset etc did not change the locked
condition.  It seems to be stuck in that screen state.  It looks like the
screen is not getting reset when powering up, the lack of beep generally
means the boot process is locked waiting for the screen to respond.  Debug
time again it would seem :(


On 27/9/19, 6:53 PM, "M100 on behalf of Eric LK"
 wrote:

>Hi,
>
>I usually use my M100 at least once or twice a week but I was away for
>almost a full month, and when I turned it on yesterday, it decided to
>take a break :o(
>
>When I turned it on, it was OK for about 3-4 seconds (the time for me
>to look at the menu clock, and to check on my watch it was still on
>time) and then the screen become white with a few black lines (notably
>the first and last lines).
>
>I pressed a few keys, hoping for a refresh problem, and then used the
>RESET button, which cleared the screen (I could still see the white
>pixels when turning the contrast dial all the way up though).
>I tried a few time to power OFF/power ON, or to do a cold reset
>(Shift+Break+RESET) but the result didn't change: Every time I got
>either a totally white screen or a white screen with a few black
>blocks (here is a picture:
>https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fpics.lefa
>uve.org%2FM100-Blocks.jpgdata=02%7C01%7C%7C0a41c556408b42a62d7008d743
>b6a089%7C84df9e7fe9f640afb435%7C1%7C0%7C637052323959256042
>;sdata=qhcaLPO7W3w2gT4TwJuQPxvLYYc3lm9H%2F9aP5H4tvDs%3Dreserved=0 ).
>
>I tried to press ENTER + beep + ENTER to check if only the display was
>affected but I got no beep.
>
>I also tried to remove the REX but it didn't have any effect at all.
>
>I checked the batteries (5.5V) and tried new ones. Still no changes.
>
>Any idea what I should try next?
>
>That was my "good" M100, so I really hope I'll be able to fix it.
>Eric
>
>PS: The whitish square visible on the picture was already there before
>the problem. It's usually clearer than the rest of the screen, but the
>text is still visible (probably one of the LCD controllers about to
>die...).

Re: [M100] Need help with bad RAM identification and replacement

[Fugu ME100]

That would be me, unfortunately there are no project pages I was just swamped 
with other things and dropped the ball :(

If you have questions etc please feel free to email me directly.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of William stewart 
mailto:wstewart2...@yahoo.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, August 23, 2019 at 4:46 AM
To: mailto:m...@bitchin100.com>>, 
mailto:chadhendrick...@sbcglobal.net>>
Subject: Re: [M100] Need help with bad RAM identification and replacement

Can anyone provide the project page for the
OSHPARK contributor Stardust?

To be clear, I'm looking for the project page, where one assumes the projects 
are discussed in detail, not the OSHPARK Link where one can order the PCBs.

TIA

William Stewart

Sent from my iPhone

On Aug 22, 2019, at 10:41 AM, 
"chadhendrick...@sbcglobal.net<mailto:chadhendrick...@sbcglobal.net>" 
mailto:chadhendrick...@sbcglobal.net>> wrote:

I ended up going the OSH Park route.  I was pleasantly surprised to find out 
that it costs the same $6.30 if you order 1 board or 3 boards.  Plus I chose 
the free shipping.

Also ordered the other parts from Digi Key.  So... total cost to me was under 
$25 for everything shipped.  This is enough parts to build 3 of them.  Not too 
bad.

Thanks for the tip!

Chad




On Wednesday, August 21, 2019, 07:18:31 PM CDT, Fugu ME100 
mailto:b4me...@hotmail.com>> wrote:


>From A000H to BFFFH is Option RAM #2 based on figure 3-5 in the 100 Reference 
>Manual.  This would cover the bad RAM.  So this looks correct.

If it is a Model 100 the modules were available form Arcade Shopper 
https://www.arcadeshopper.com/wp/?page_id=11#!/8k-RAM-module-for-Model-100/p/104430801/category=28313042<https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.arcadeshopper.com%2Fwp%2F%3Fpage_id%3D11%23!%2F8k-RAM-module-for-Model-100%2Fp%2F104430801%2Fcategory%3D28313042=02%7C01%7C%7Cfad5f45a1462444cb82e08d727bf8cad%7C84df9e7fe9f640afb435%7C1%7C0%7C637021575957814064=Zm2zYgxccp4APvqynwnMJgs1KIM%2FwyZl4GGra50UlRo%3D=0>
  but they appear to be out of stock.

There are a few list contributors who also build 100 modules they might have 
some built and OSH Park has the PCBs to build your own modules if you want to 
go down that route for example:  
https://oshpark.com/shared_projects/V0tpeuMg<https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Foshpark.com%2Fshared_projects%2FV0tpeuMg=02%7C01%7C%7Cfad5f45a1462444cb82e08d727bf8cad%7C84df9e7fe9f640afb435%7C1%7C0%7C637021575957814064=p3fN0Ls1IUL4LD%2FBIaqIthOXGU4a2d7PbPIC2tMTbHw%3D=0>
 there are others out there


From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of 
"chadhendrick...@sbcglobal.net<mailto:chadhendrick...@sbcglobal.net>" 
mailto:chadhendrick...@sbcglobal.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Wednesday, August 21, 2019 at 4:31 PM
To: "m100@lists.bitchin100.com<mailto:m100@lists.bitchin100.com>" 
mailto:m100@lists.bitchin100.com>>
Subject: [M100] Need help with bad RAM identification and replacement


Can someone verify for me that B000-BFFF would be part of the M7 (Option RAM 
#2) RAM chip?  Of the four RAM chips, this is the second one from the left.

Second question is... where can I buy replacement RAM for this?  I am good with 
a soldering iron so I realize I will have to desolder the existing bad RAM and 
socket it and pop in the new RAM.

Re: [M100] Need help with bad RAM identification and replacement

[Fugu ME100]

>From A000H to BFFFH is Option RAM #2 based on figure 3-5 in the 100 Reference 
>Manual.  This would cover the bad RAM.  So this looks correct.

If it is a Model 100 the modules were available form Arcade Shopper 
https://www.arcadeshopper.com/wp/?page_id=11#!/8k-RAM-module-for-Model-100/p/104430801/category=28313042
  but they appear to be out of stock.

There are a few list contributors who also build 100 modules they might have 
some built and OSH Park has the PCBs to build your own modules if you want to 
go down that route for example:  https://oshpark.com/shared_projects/V0tpeuMg 
there are others out there


From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of 
"chadhendrick...@sbcglobal.net" 
mailto:chadhendrick...@sbcglobal.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Wednesday, August 21, 2019 at 4:31 PM
To: "m100@lists.bitchin100.com" 
mailto:m100@lists.bitchin100.com>>
Subject: [M100] Need help with bad RAM identification and replacement

Can someone verify for me that B000-BFFF would be part of the M7 (Option RAM 
#2) RAM chip?  Of the four RAM chips, this is the second one from the left.

Second question is... where can I buy replacement RAM for this?  I am good with 
a soldering iron so I realize I will have to desolder the existing bad RAM and 
socket it and pop in the new RAM.

Re: [M100] M100 display not working, all else seems good

[Fugu ME100]

Great!

The same thing happened to someone else on the list -  just very recently.  I 
think C82 was the culprit too :)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of 
"chadhendrick...@sbcglobal.net<mailto:chadhendrick...@sbcglobal.net>" 
mailto:chadhendrick...@sbcglobal.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, August 19, 2019 at 9:18 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] M100 display not working, all else seems good

BINGO!

That was it!

C82 was one of the capacitors that had leaked and I replaced.  Right in that 
same area is the trace between T23 (Emitter) and Pin 4 of the display 
connector.  I checked and there was no continuity.

I ran a new wire.  Powered it up... and have a nice beautifully functioning 
display now!

Thank you so much for your help.

Another M100 returned to life!

Chad



On Monday, August 19, 2019, 10:52:31 PM CDT, Fugu ME100 
mailto:b4me...@hotmail.com>> wrote:


On my machine it swings from about 1V to around 3.5V.  The 1.25V is way  too 
low I feel.  Is there a good connection from T23 to pin 4?  It sounds as if 
that line might be disconnect or there is a problem with the contrast voltage 
generation.

Is VR1 giving a good voltage input?

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of 
"chadhendrick...@sbcglobal.net<mailto:chadhendrick...@sbcglobal.net>" 
mailto:chadhendrick...@sbcglobal.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, August 19, 2019 at 8:24 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] M100 display not working, all else seems good

With one lead on Pin 4 and one lead on GND, it is maxing out at about 1.25v and 
goes down to around zero.  Is this acceptable?

Thanks,
Chad

Re: [M100] M100 display not working, all else seems good

[Fugu ME100]

On my machine it swings from about 1V to around 3.5V.  The 1.25V is way  too 
low I feel.  Is there a good connection from T23 to pin 4?  It sounds as if 
that line might be disconnect or there is a problem with the contrast voltage 
generation.

Is VR1 giving a good voltage input?

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of 
"chadhendrick...@sbcglobal.net" 
mailto:chadhendrick...@sbcglobal.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, August 19, 2019 at 8:24 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] M100 display not working, all else seems good

With one lead on Pin 4 and one lead on GND, it is maxing out at about 1.25v and 
goes down to around zero.  Is this acceptable?

Thanks,
Chad

Re: [M100] M100 display not working, all else seems good

[Fugu ME100]

How much is the contrast voltage adjusting?

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of 
"chadhendrick...@sbcglobal.net" 
mailto:chadhendrick...@sbcglobal.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, August 19, 2019 at 7:49 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] M100 display not working, all else seems good

I also checked the contrast signal and it is adjusting with the contrast pot.

Re: [M100] M100 display not working, all else seems good

[Fugu ME100]

Yes the machine sounds as if it is healthy, even the display is present.  The 
boot up will hang if it cannot read back from the display – so it would not 
beep.  I would guess the contrast line has insufficient swing.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of 
"chadhendrick...@sbcglobal.net" 
mailto:chadhendrick...@sbcglobal.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, August 19, 2019 at 7:52 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] M100 display not working, all else seems good

I am able to blindly go into Basic and type "beep" and it beeps.  I even make a 
program:

10 beep
20 goto 10
run

and it beeps over and over until I break.

Since I am able to do this, wouldn't this mean that my RAM is OK?

Thanks,
Chad

Re: [M100] M100 display not working, all else seems good

[Fugu ME100]

This seems very similar to a problem a few weeks ago where the contrast signal 
was absent on the LCD connector.   One of the leaking caps had eaten through 
the contrast control line.   A quick check of the continuity between pin 4 on 
the LCD connector and the base of T23 would confirm that is what has happened 
(or not).

IIRC the original poster solved their problem so hopefully they can chime in 
too with any tips.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, August 19, 2019 at 6:47 PM
To: "m...@bitchin100.com" 
mailto:m...@bitchin100.com>>
Subject: Re: [M100] M100 display not working, all else seems good

I would start checking the signals at the LCD connector.
Ensure the voltages are present, and that the contrast signal is also there and 
adjusting well.

Sometimes if you hold the screen at different angles you can see faint text.  
Give that a try.

Seems like you m100 is mostly working...

On Monday, August 19, 2019, 
chadhendrick...@sbcglobal.net 
mailto:chadhendrick...@sbcglobal.net>> wrote:
Hello,

New to the list.  Just pulled my Model 100 out of storage where it had been for 
at least 20 years.

It would not power up so I have replaced many of the electrolytic capacitors 
(several of which were obviously leaking) including all the ones near the power 
switch (C83, C82, C85, C84, C90, C86, C92) and also four 10uF caps over nearer 
the modem switches (C49, C50, C54, C55).

It will now power up but there is no display.

I know it is powering up because I am able to blindly go into Basic and type 
"beep" and the speaker beeps.  This also proves the keyboard is working.

I am powering with four fresh AA batteries.

I've tried adjusting the contrast knob.  I've tested the NiCD battery and it is 
showing 4.4v.

I've tested VDD (+5v), VB (+5v), and VEE (-5V) and all test solidly good.

Ribbon cable has been reseated and looks good.

When I do a Reset, I can hear a slight click from the speaker so that button is 
working.  I have tried doing a cold reset (control-shift-break-reset) and still 
no display.

When I power off, the battery LED flickers quickly so that is working.

What would be my next steps?  Is there a good place on the LCD to test to make 
sure it is getting good power?  If so, where?

Thanks in advance,
Chad

Re: [M100] In the hospital

[Fugu ME100]

Sounds like a required upgrade :)  Here's to a speedy recovery!

On 19/7/19, 8:05 AM, "M100 on behalf of Ken Pettit"
 wrote:

>Hey Gang,
>
>I had to come to the hospital again on Wednesday because of cardio
>issues.  After the angiogram yesterday, the Dr. told me I need bypass
>surgery, which they will schedule for sometime early next week.  I'm
>still hanging out here while waiting, which is kinda why I have time to
>send emails on the list :)
>
>Just wanted everyone to know in case things don't go well and you never
>hear from me again, at least you will know what happened. Only a small
>chance of that though ... they do a LOT of open heart surgery per day
>here (successfully), so they are pretty good at it.
>
>Ken

Re: [M100] Non working display on my m100

[Fugu ME100]

On my M100 with no screen attached the V2 voltage ranges from about 1.5V to 
almost 3V.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of George Hines 
mailto:mrthreepla...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, July 6, 2019 at 3:48 PM
To: mailto:m100@lists.bitchin100.com>>
Subject: [M100] Non working display on my m100

Thanks for the suggestions and tips!

I've checked c105 and c106 and they are close to their speced values.  I 
checked the variable resistor and it seems to be okay.   I'll recheck the v2 
range again, it does seem like it should have a greater range.

Re: [M100] Non working display on my m100

[Fugu ME100]

The contrast voltage appears to be too low if memory serves the voltage swing 
needs to be greater than 300mV, the manual indicates the swing should be around 
4V (pg 38).  It could be that VR1 needs cleaning or at least checking out or 
c106/c105 might have problems.

The display sounds like it is working just the contrast voltage is too low.  If 
the display were dead the BASIC BEEP command would not work – the boot sequence 
checks the display and hangs if it does not read back correctly.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of George Hines 
mailto:mrthreepla...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, July 5, 2019 at 10:15 AM
To: mailto:m100@lists.bitchin100.com>>
Subject: [M100] Non working display on my m100

I checked v2 at the interface and it varies from 1.4 to 1.7 volts as I adjust 
the contrast.

Re: [M100] dsub 25 hood that fits

[Fugu ME100]

I went for a slightly different solution and made a level shifter board that 
fits into the TPDD 8x2 plug on one end with a DB25 towards the Model T, then 
used an off the shelf straight through serial cable to connect the TPDD to the 
Model T.  Works really well no need to crimp anything just all very 
straightforward soldering :)

Did need to ‘extend’ the board a little to get the connector to fit properly 
into the TPDD.  I used an edge solder approach as you can see (Hope the image 
is OK to attach?)  I didn’t bother with a enclosure the board is really tiny, 
although thought about using shrink tubing.It could of been a DB9 but I had 
a lot of DB25s to use up :)

[https://644db4de3505c40a0444-327723bce298e3ff5813fb42baeefbaa.ssl.cf1.rackcdn.com/97c940af13754774f6a8530e6e639a35.png]


From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Brian White mailto:bw.al...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, June 1, 2019 at 5:14 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] dsub 25 hood that fits


Another idea is make a different pcb which goes on the tpdd end instead of the 
m100 end. A crimp-on 2x4 idc (he said, redundantly, given what idc stands for) 
plug does not fit in the hole in a tpdd, but maybe a female 2x4 pcb header 
does. If you could just extend a female pcb header to stick up off a pcb 
surface just a little more, then you could have a small pcb that sits flat 
against the back of the tpdd, and has a plug that sticks in to the tpdd. That 
would eliminate the *excruciating* process of crimping individual tiny dupont 
connector pins I'm using right now. Then just cut the db9 off a common modem 
cable and solder that to the pcb, and you have a full cable that was much 
easier to build, and which fits in a M100. (Rick's original cables were easy 
enough for him to build only because he used FB100 cables to provide the tpdd 
plugs. I'm going for more available parts.) Only remaining problem there is 
some sort of enclosure for the pcb. Maybe the 2x4 header can be a right-angle 
type, and so the pcb sticks out 90 degrees from the tpdd in line with the 
cable. Then, assuming the whole pcb is small so it doesn't stick out too far, 
and give it a little dog-bone shape, you could zip-tie the serial cable to it 
and enclose the whole thing in simple heat shrink. I don't know if you can get 
a right-angle header to stick out far enough from the side of a pcb to allow it 
to reach in to the pins in the tpdd though. And I don't think there's enough 
room for the pcb to extend inside the hole either.

Re: [M100] M100 memory

[Fugu ME100]

HI

Yes they are 8K modules and there are a few options to build or buy new modules 
:)

The Tandy Wiki http://tandy.wiki/Model_100_RAM is a great resource for 
information on parts etc for the Model Ts.

A few people on the list create Model T parts in their spare time, as hobby, 
they might have some for sale.

Blank PCBs are available on the PCB sharing part of  OSHPark 
https://oshpark.com/shared_projects if you want to build your own, searching 
the sharing archive can be painful though.

You could check out Arcade Shopper for prebuilt modules at  
https://www.arcadeshopper.com/wp/?page_id=11#!/100-102-200/c/28313042/offset=0=nameAsc
 they sell parts for the Model T and other classic machines.

eBay sometimes throws up individual parts for the Model Ts.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Ed Graffius mailto:quaddri...@aol.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, May 18, 2019 at 5:49 AM
To: mailto:m100@lists.bitchin100.com>>
Subject: [M100] M100 memory

Ok, Its working well and I have been poking around (but not peeking if bad 
BASIC puns are allowed).  I need another 8K

each module must be 8 k right?  is there a source for them today?  likely not 
new...but used?  NOS?  salvage?

I need to find the cassette adaptor pinout and a plug - have a solution to 
trysave files in thru the media player on THIS machine as .wav using the 
mic in jack and loading using the speaker outa sort of 'virtual cassette'

Re: [M100] Non-charger

[Fugu ME100]

Sometimes a cold boot can help after a NiCd battery replacement.

Then check the Vdd and Vee voltages are +5V and –5V respectively.   The voltage 
on the battery should be about 3.7V if it is charging OK.

It could be powering on just the screen is dim.  Try powering on, hit return 
(this takes you to BASIC) and then type BEEP and return.  There should be a 
beep if the unit is powering up but the screen is not working.   If the screen 
is dim the –5V (Vee) might be really low.

The memory protect switch is set correctly?  I routinely forget to set this 
switch correctly when I take a machine out of storage :(

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Chris Fezzler mailto:fezz...@yahoo.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Tuesday, April 23, 2019 at 12:31 AM
To: Model 100 Discussion 
mailto:m100@lists.bitchin100.com>>
Subject: [M100] Non-charger

I took a Model T out of storage and it was completely dead and would not take a 
charge.
I figured I'd use the opportunity to replace internal battery anyway.

Installed the new battery and it started right up, albeit with a Low Battery 
light.  So I assumed it just needed an overnight charge and would be as good as 
new.

Just got home from work and it is dead as a doorknob again after being plugged 
into wall wort.

I can solder and have a digital multimeter.  Some clues on what to check?  I 
assume it is not charging.

Re: [M100] TeraTerm - still not communicating

[Fugu ME100]

Yes unfortunately.  Just need a male/male adapter.  Should be easy to find.  
After that it should work though.  :-D

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Thomas Morehouse 
mailto:nutmegfl...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, April 5, 2019 at 2:24 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] TeraTerm - still not communicating


Oops - can't do that.  The null modem adapter is female/female, so I need to 
buy yet another adapter to try this.  Good grief.

Re: [M100] TeraTerm - still not communicating

[Fugu ME100]

The M102 serial port has 25pins located on the rear right hand side and 
labelled RS-232-c with 25 female ‘pins’.  The only 9 pin port on the M102 is 
the barcode reader port located on the mid-left hand side.  Just wanted to 
check that the correct port was being used to connect to the M102 for serial 
comms with the laptop?

There should be an adapter with the USB – Serial cable that converts the 9pin 
connector on the cable to a 25pin connector.   Then it will most likely need a 
25pin gender changer to make it into a male connector for plugging into the 
female 25pin connector on the M102.


From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Thomas Morehouse 
mailto:nutmegfl...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, April 5, 2019 at 1:54 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] TeraTerm - still not communicating




The M102 port is nine pins (male).  So you're saying to "short" pins 2 and 3 in 
that port as the other MikeS says "2nd and 3rd from the right on the bottom 
row".

Re: [M100] Display goes blank when plugged into power adapter

[Fugu ME100]

Which model transformer did you use?

I have been looking for a replacement but have not really found one.
Thanks!

On 2/4/19, 11:28 AM, "M100 on behalf of Josh Malone"

wrote:

I've also had to replace the transformer on a unit, though that one was
exhibiting complete power-on failure.

Re: [M100] Lighter rows of pixels on LCD

[Fugu ME100]

I don¹t think you damaged the screen it was probably like that before you
touched it.  They are very old machines and way beyond their expected EOL.
 Even fully functional machines can stop working after time in storage. I
recently took out my favorite 102 after a few weeks of none use and it
would not power up even after a cold reboot.  Checked the batteries etc
all fine opened it up checked the voltages internally, everything looked
perfect, switched it on again and it worked.  So they age and will fail.
I found patience is a virtue with these machines :)

The e-Ink idea sounds a great idea for a screen replacement.  Wonder if
there is a version that has a similar size?  It would probably be quite
easy to build the HW to map the LCD screen commands to the e-Ink screen.
 


On 26/2/19, 9:15 PM, "M100 on behalf of Andrew Kennedy"

wrote:

>Great, so it sounds like I damaged a chip by not taking enough care with
>the LCD board. And I was so proud of myself!
>Oh well, thanks for the help guys. I unplugged and replugged the flex
>cable that connects to the LCD board, but I'm not going to mess with it
>any further on my own.
>
>John, I do wonder if e-Ink would be a good replacement. It doesn't have
>to be high DPI, and the next generation should be plenty fast for the
>Model T's purposes if the current generation isn't yet.
>I bought a new e-reader recently, and I love the screen. It looks great
>in any lighting, and uses very little power because it only uses
>electricity to change a pixel's on/off state.
>

Re: [M100] Lighter rows of pixels on LCD

[Fugu ME100]

I have used de-oxit on the edge of the elastomer to pcb contact in the past – 
very, very sparingly to try and clean the PCB contacts.  Then used a piece of 
stiff card to very very gently push the elastomer in an attempt to clean up the 
contacts.  This tends to work for lines that are blank rather than dim.   The 
line is totally gone in this case either horizontally or vertically and they 
tend not to repeat.

With lines that are just a little dimmer than the rest I have not found a good 
solution.  If they are paired like this example it implies to me that the 
driver chips are no longer working properly.   The screen is split in two parts 
driven by the same horizontal chips.  So the 1&2 are the same as 33 & 34 lines.

As Jeff mentions check the –5V is close to –5V eg –4.89V or higher.

The problem is not related to the battery replacement.   It is simply the age 
of the machine, the old LCD displays were prone to heat and moisture problems 
and of course the chips themselves do age.

Don’t be tempted to take the screen apart they are almost impossible to get 
back together and work – yes I have tried it :)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Jeffrey Birt mailto:bir...@soigeneris.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Tuesday, February 26, 2019 at 1:17 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Lighter rows of pixels on LCD

Hi Andrew,

The LCD glass is electrically connected to the PCB via an elastomeric ‘zebra’ 
strip. This is sort of like a silicone rubber strip with stipes of conductive 
material embedded to make electrical contact. If something got under between 
the PCB and zebra strip it might cause an issue like this. The metal frame 
around the LCD is what applies pressure to hold things in place. You can apply 
a bit of pressure to the edges to see if it changes.

Also, check you power supply voltages. If the -10V for the LCD is low, it could 
cause problems and perhaps some driver chips would be more sensitive to the low 
voltage than others?

Jeff_Birt (Hey_Birt!)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
On Behalf Of Andrew Kennedy
Sent: Tuesday, February 26, 2019 2:42 PM
To: m100 mailto:m100@lists.bitchin100.com>>
Subject: [M100] Lighter rows of pixels on LCD

Hi folks, thanks again for the advice the other day. I just replaced my NiCd, 
which had a light amount of leakage on the barrel but didn't appear to have 
reached the PCB. I put a NiMh in there, and the computer is plugged in to 
charge it up for a while.
However, when I turn it on I'm noticing an annoying defect, there are two bars 
on the screen whose pixels are lighter than the others. The bars are at rows 
1&2, and 33&34, counting 0 as the first row. The pixels still turn black, just 
not as black as the other rows of pixels.

I tried searching the mail archives but didn't find any discussion about this.
Could it be that the new battery just needs to charge more?
I'm going to reseat the ZIF cable, but if there are any other ideas please let 
me know.

- Andrew

[M100] Model 600 [was Re: ebay seller]

[Fugu ME100]

I have one at the moment. I would have to agree wth the comments it is big and 
heavy – it has a huge NiCad built in. The 600 is a curious machine, a 'missing 
link' from the Model T to the MS-DOS machines.  I do not use it all, it needs 
to sit on a desk it is so heavy unlike my favorite 102 which can be used 
anywhere.

When the seller shipped mine they did not pack it too well and with the heavy 
internal battery the upper case was pretty much smashed to pieces when the 
NiCad battery broke free in transit.  The plastic is brittle and it does break 
very easily.  So make sure the seller packs it really well if you decide to go 
ahead.   Getting it working was quite a challenge as it needed the case 
rebuilding and parts replaced due to age and the shipping disaster.

The Model 600 WiKi is a good resource to start to repairs.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Tuesday, February 26, 2019 at 6:23 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] ebay seller

I had 2 at one point. I liked the challenge of getting it working but in the 
end I didn't have a use relative to the M100.  I felt similarly about the DVI.  
Had 2 but got passed them along eventually.
A bit too big, bulky, heavy etc.

On Tue, Feb 26, 2019 at 9:19 AM Tom Dison 
mailto:fretina...@gmail.com>> wrote:
There is a model 600 for sale at a good price on eBay, but I'm kind of 
hesitant. It seems to be quite the oddball model in the series. Does anyone 
have experience with it?

Re: [M100] ebay seller

[Fugu ME100]

The second one is actually my design.   Although it does not provide 96K only a 
regular 8K module for the M100.

Curious as to how it was copied from OSHpark, they would have to get the 
gerbers?  OSHPark provide 3 for $6.30 and free shipping,  so the ebayer is 
quite expensive.

I guess they left my Copyright on :)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Brian White mailto:bw.al...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, February 25, 2019 at 7:51 PM
To: Model 100 Discussion 
mailto:m100@lists.bitchin100.com>>
Subject: [M100] ebay seller

Is this somebody here, or does anyone recogize or know them?
http://ebay.com/itm/113662788499/

They are not violating any actual laws, because this pcb design is explicitly 
placed in the public domain. It's just that it would be at least minimally 
considerate to give a little attribution where they got something from.

They even (re)used the pictures right from the original oshpark listing:
https://oshpark.com/shared_projects/8HMgno1x

The designer (and oshpark account) is Jayeson Lee-Steere and the oshpark pics 
came from me.
The ebay seller is not Jayeson nor does he know them, so it's not a deal he set 
up with the seller.

Same seller:
http://ebay.com/itm/113662802362/
and the origin:
https://oshpark.com/shared_projects/V0tpeuMg

That one actually says copyright right on it. I believe this one is Steven 
Adolph right?

--
bkw

Re: [M100] Rex vs DVI

[Fugu ME100]

The DVI-DOS loads from 0xE000 -> 0xF700.  It also taps into the command
processor for BASIC to add in the extra DVI commands.  If REXMGR or
anything else writes over those locations with its own jumps etc then the
DVI commands will not be found (FC error).  It would appear that is what
is happening.  As mentioned yesterday there might be some tools that can
save and restore the DVI commands allowing some co-existence?



On 20/2/19, 9:28 AM, "M100 on behalf of Greg Swallow"
 wrote:

>Yep, DVI-DOS gets dumped.
>
>1) Cold Start to clear MT
>2) Turn on DVI
>3) Insert boot disk at prompt
>4) Hit reset on MT
>5) Verify DVI-DOS loaded with LFILES
>6) In BASIC and CALL 63012
>7) REXMGR in Menu, go to BASIC and DVI-DOS not working; LFILES gives a FC
>error.
>
>
>God Bless,
>
>GregS <><
>
>- Original Message -
>From: "Josh Malone" 
>To: m...@bitchin100.com
>Sent: Wednesday, February 20, 2019 9:55:01 AM
>Subject: Re: [M100] Rex vs DVI
>
>I don't think you're missing anything. I just don't think DVI-DOS and
>REXMGR can coexist. It didn't occur to me when Stephen posted his method
>that REXMGR was also a problem, not just TS-DOS. Once you load DVI-DOS, is
>it possible to re-load REXMGR or does that Smurf up the loaded DVI-DOS?
>

Re: [M100] Rex vs DVI

[Fugu ME100]

Interesting question, are there any uniquely DVI DOS applications?  Or were 
they simply unique commercial packages e.g payroll, stock control etc, that 
were never released widely?

The TPDD drive seems to be more useful with its portability and plays to the 
strength of the Model T in its day.

Kind of curious myself, possibly why DVI BASIC and TS-DOS co-existence was not 
considered important at the time?

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Tuesday, February 19, 2019 at 9:18 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Rex vs DVI

seems like DVI is a failure from the perspective of ... what software is 
actually written that can leverage it?
Are there any applications?
(ties into my objective of a video card for M100...DVI compatibility may be 
useless)

Re: [M100] TPDD emulator on Arduino

[Fugu ME100]

Yes the ESP-12 works really well.  The ESP-8266 is now integrated with the 
Arduino IDE so moving code around is a breeze.  Although there are still some 
issues with sleep etc.  There are also a bunch of libraries like WiFi Scan, 
FTP, TELNET, NTP and OTA updating which make it quite simple to add in those 
features.  The 8266 is a bit of a power hog but otherwise it worked really well 
as a WiFi link and SD-Card interface.I did put together a OSH board some 
time ago to build an ESP-TPDD based interface, it should be shared on OSH

In my case I just used the TELECOM program to set up the FTP or TELNET.  The 
FTP is only to the local SD-Card which can then be accessed via TP-DOS.  The 
only clunky part was booting from the ESP-TPDD as it does not support the 
control lines – too few pins – to react to the Model Ts serial pin status.

There are also some ESP-12 boards available with RS-232 ports that can be 
plugged directly into the Model T, I do not have the link though.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of c646581 mailto:c646...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Wednesday, January 30, 2019 at 11:46 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] TPDD emulator on Arduino

I've been thinking about an ESP8266-based TPDD emulator that can link up to an 
FTP site or act as a telnet to serial bridge at the flip of a switch.

Re: [M100] Unable to Load TEENY to MT

[Fugu ME100]

The REX board needs to be seated all the way down.  It should feel firmly
inserted into the socket, it might not be making good contact all the way
round.  The REX programmer will run to completion even if the board is not
properly inserted. 

After running CALL63012 does the machine lock up or return straight to the
MENU screen?  If if returns to the menu immediately then in general the
REX is not being seen, a bad REX will usually cause the MT to lock up when
trying to start the REXMGR - if the onboard FLASH is corrupted.



On 29/1/19, 12:51 PM, "M100 on behalf of Greg Swallow"
 wrote:

>I haven't run a RAMTST on the first two MT I tried, but I have on this
>latest. I've been using it with the SuperROM for some time. I hadn't
>intended to use the Rex with this one, but I am getting farther in the
>process. Am figuring more along the connection is the problem some how.
>If I can't get it functioning today or Wednesday, I'll see what I can do
>with Greg over at ArcadeShopper.com.
>
>God Bless,
>
>GregS <><

Re: [M100] Unable to Load TEENY to M1

[Fugu ME100]

Must admit I have never had that happen, all the faults I have seen usually 
allow the RF149.co run to completion.   I have plugged them in backwards a few 
times though :-D Especially when trying to debug crashing programmings.

I have had problems where the +5V has failed and corrupted a REX, not sure how 
that can happen, but reprogramming it usually brings it back to life.   Yes 
sometimes I forget the REX is in there when playing with system bus plugins.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 27, 2019 at 2:07 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Unable to Load TEENY to M1

the fact that you say that 
RF149.CO
 hung during burning of a file (in this case the RexManager software) to me 
says that the flash is stalled in the "BUSY" state.   One of 2 things
(1) REX is improperly seated
(2) REX has a hardware defect

In my experience contrary to Fugu (i am very reluctant to differ from him 
ever!) all of my REX software can hang when the Flash gets stuck in BUSY state. 
   This happens when for example the software tries to REWRITE a "1" to an 
address that has already been WRITTEN to "0" value.   This only happens if the 
software is buggy, or somehow there is a hardware defect, like a malfunctioning 
address line connection.

..Steve


On Sun, Jan 27, 2019 at 4:58 PM Greg Swallow 
mailto:gswal...@mchsi.com>> wrote:
I did get farther, even with TS-DOS loaded. Ran 
RF149.CO
 from MENU after the LOADM. It seem to start ok, but then nothing seemed to 
happen when left it half the night loading 0:RF149.BX. Maybe I should have let 
go all night.

God Bless,

GregS <><
- Original Message -
From: John R. Hogerhuis mailto:jho...@pobox.com>>
To: m...@bitchin100.com
Sent: Sun, 27 Jan 2019 05:37:32 -0500 (EST)
Subject: Re: [M100] Unable to Load TEENY to MT

But it gave no error...

I think it loaded. Meaning when you typed loadm it copied it's contents to
55302.

Not sure why the clear address is 55000. The program starts at 55302. Maybe
the program uses the gap as a scratchpad.

I'm guessing the beep is from the program itself. Maybe it's done or maybe
it's giving you an error.

-- John.


On Sun, Jan 27, 2019, 12:24 AM Greg Swallow 
mailto:gswal...@mchsi.com> wrote:

> CLEAR0,55000: 
> LOADM"RF149.CO"
>  gives
>
> Top: 55302
> End: 60148
> Exe: 55302
>
> Hope this helps
>
> GregS <><
>
>
> - Original Message -
> From: "John R. Hogerhuis" mailto:jho...@pobox.com>>
> To: m...@bitchin100.com
> Sent: Sunday, January 27, 2019 12:03:56 AM
> Subject: Re: [M100] Unable to Load TEENY to MT
>
> What did you try to "clear out" ts-dos?
>
> I don't think that beep has anything to do with TS-DOS. When a CO file
> beeps on load, it's because the CLEAR statement is wrong. And if you typed
> the CLEAR statement and it gave no error, then you have sufficient room to
> run the utility.
>
> If it beeps anyway, maybe the program is running but just beeps. Who knows.
>
> Do me a favor, do the CLEAR statement, and 
> LOADM"RF149.CO
> from the BASIC prompt, not from the main menu and tell us what you see.
>
> If it prints out the CO file's header, we can figure out if
>
> a) The clear statement is right
> b) The beep is coming as a BASIC load issue, or for some other reason.
>
> -- John.
>

Re: [M100] Unable to Load TEENY to MT

[Fugu ME100]

Ah interesting.  So perhaps the method should be to perform the DOS-ON/DOS-OFF 
first and then clearmem.  Rather than just clearmem.   That might clear 
everything out properly.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of "John R. Hogerhuis" mailto:jho...@pobox.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 27, 2019 at 2:08 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Unable to Load TEENY to MT



On Sun, Jan 27, 2019 at 1:48 PM Fugu ME100 
mailto:b4me...@hotmail.com>> wrote:

  *Simply clearing a piece of RAM does not undo anything RAM TPDD might of 
done to various hooks, timers or buffers.

True, but that is what the DOS-ON/DOS-OFF command in TS-DOS does. It hooks / 
unhooks the BASIC extensions.

If it does not, it is a bug in TS-DOS. Which of course is possible, it wouldn't 
be the first bug discovered.

-- John.

Re: [M100] Unable to Load TEENY to MT

[Fugu ME100]

Just a couple of observations from programming a few REXs :)

  *   Even if the REX were dead RF149.co always seems to run to completion. I 
have run it with a few faulty REXs.  It will complete and be quite happy. Then 
when you try to perform the BASIC CALL it fails.  If the REX has failed then 
what happens is either the erasing part runs in a few seconds rather than 30s 
and the programming part will run quite quickly.  It will still download both 
ROM image files from the TPDD drive.  In fact it looks like it completes 
programming – but it does not.  Locking up trying to download the ROM images 
would indicate to me that it is having a problem loading the ROM images from 
the TPDD drive.  The RF149.co runs regardless of the state of the REX.  The 
only time this is not the case is if the REX is inserted backwards, but then 
the Model T locks up :)
  *   The fact RAM TPDD has been loaded and, I believe, inserts hooks in 
various places to me implies that it could conflict with the RF149.co internal 
DOS program, whereas TEENY I believe is quite clean in that respect.  I only 
know from bitter experience that when I was attempting to program a REX 
originally using RAM TPDD it would cause problems – including the beep.  
Whereas using TEENY caused no problems.  I can only conclude that RAM TPDD 
somehow conflicted with the REX programming using RF149.co.  Simply clearing a 
piece of RAM does not undo anything RAM TPDD might of done to various hooks, 
timers or buffers.

I think a cold boot followed by installing TEENY then downloading RF149.co will 
work.  Whether the REX is dead or not RF149.co will run to completion.  Only 
when you do the BASIC CALL do you find out if it is successful :-D  If it takes 
<2mins to program,  the REX is probably faulty, if it takes approx 5mins it is 
probably good.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of "John R. Hogerhuis" mailto:jho...@pobox.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 27, 2019 at 1:25 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Unable to Load TEENY to MT



On Sun, Jan 27, 2019 at 12:55 PM Fugu ME100 
mailto:b4me...@hotmail.com>> wrote:
The RAM TPDD is most likely conflicting with the the REX program.  The best 
method is to use TEENY to download the 
RF149.CO<https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2FRF149.CO=02%7C01%7C%7C493abc44724140a7c47308d6849dd981%7C84df9e7fe9f640afb435%7C1%7C0%7C636842210819854880=2MeQKbFM1wovZpHCFW8IAIksrgnyH5sFeGDlmQWJr30%3D=0>
 file.  I have never used the RAM TPPD to program a REX

Well.

TEENY is fine, and Steve says that's what he tested with, so I agree that's the 
best way to go.

But let me do my small part to prevent cargo cult misunderstandings though...

Saying TSDOS "conflicts" with 
rf149.co<https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Frf149.co=02%7C01%7C%7C493abc44724140a7c47308d6849dd981%7C84df9e7fe9f640afb435%7C1%7C0%7C636842210819864879=bSYsn0piPZ4QQtSOoqz3wkmI549OZgOc7kF46BfMivM%3D=0>
 doesn't make any sense to me.

RAM based DOSes that aren't running don't conflict with other CO programs. If 
they did, there wouldn't be much point to them, because part of the point of a 
DOS is to be able to inload CO files, and then run them.

When a DOS inloads a CO program, it inloads it into the file system portion of 
RAM. If you don't have enough RAM to add the file to the RAM file system, the 
DOS will give you an error.

But that didn't happen... it loaded the CO into the file system. Note that the 
inload just places it in the file system. It doesn't run it. It doesn't copy 
the program to the place it needs to run. If it did, it might overwrite itself!

But it doesn't, because that's not how it works.

Then you exit the DOS, you enter a CLEAR statement if the file needs to run 
lower than whatever HIMEM is currently set to, likely because of a previous 
clear for other programs you run (like the DOS).

The program then launches and runs.

The one area you might say this is not true is that TS-DOS can be "hooked" into 
BASIC to add some extensions. Those extensions must be copied and run from 
somewhere, so it's possible they could conflict.

The most likely thing IMO is his REX is not making contact or it is faulty in 
some other way.

As you say the burn should complete in 5 minutes.

Steve does your program ever beep for any reason?

:-)

-- John.

-= Model T's Forever =-

Re: [M100] Unable to Load TEENY to MT

[Fugu ME100]

The RAM TPDD is most likely conflicting with the the REX program.  The best 
method is to use TEENY to download the RF149.CO file.  I have never used the 
RAM TPPD to program a REX.

Running the REX programmer to completion should only take around 5mins.  The 
erasing part takes about 20-30s then downloading the RF149.BR file takes a few 
minutes.  It will then load the tsd100.bx file – which takes a few more 
minutes.  A progress bar will show as they are downloaded.  Both of these files 
need to be on the TPDD drive.  The REX programmer will automatically load in 
the two ROM files.  RF149.co is fully self contained and does not require 
anything else to be loaded.

On Sun, Jan 27, 2019 at 3:06 PM Greg Swallow 
mailto:gswal...@mchsi.com>> wrote:
I thought that might be the case and tried running after the LOADM. it seemed 
to be working. It wiped the bank(s) and started loading 0:RF149.BX -- I think 
it was, but didn't indicate any progress after a few hours I stop it. Maybe I 
should've let it keep going. I'll be off work again Tuesday and give it a try, 
if I don't get a chance today. Spending time with in-laws today.

God Bless,

GregS <><

- Original Message -
From: John R. Hogerhuis mailto:jho...@pobox.com>>
To: m...@bitchin100.com
Sent: Sun, 27 Jan 2019 05:37:32 -0500 (EST)
Subject: Re: [M100] Unable to Load TEENY to MT

But it gave no error...

I think it loaded. Meaning when you typed loadm it copied it's contents to
55302.

Not sure why the clear address is 55000. The program starts at 55302. Maybe
the program uses the gap as a scratchpad.

I'm guessing the beep is from the program itself. Maybe it's done or maybe
it's giving you an error.

-- John.


On Sun, Jan 27, 2019, 12:24 AM Greg Swallow 
mailto:gswal...@mchsi.com> wrote:

> CLEAR0,55000: 
> LOADM"RF149.CO"
>  gives
>
> Top: 55302
> End: 60148
> Exe: 55302
>
> Hope this helps
>
> GregS <><
>
>
> - Original Message -
> From: "John R. Hogerhuis" mailto:jho...@pobox.com>>
> To: m...@bitchin100.com
> Sent: Sunday, January 27, 2019 12:03:56 AM
> Subject: Re: [M100] Unable to Load TEENY to MT
>
> What did you try to "clear out" ts-dos?
>
> I don't think that beep has anything to do with TS-DOS. When a CO file
> beeps on load, it's because the CLEAR statement is wrong. And if you typed
> the CLEAR statement and it gave no error, then you have sufficient room to
> run the utility.
>
> If it beeps anyway, maybe the program is running but just beeps. Who knows.
>
> Do me a favor, do the CLEAR statement, and 
> LOADM"RF149.CO
> from the BASIC prompt, not from the main menu and tell us what you see.
>
> If it prints out the CO file's header, we can figure out if
>
> a) The clear statement is right
> b) The beep is coming as a BASIC load issue, or for some other reason.
>
> -- John.
>

Re: [M100] Unable to Load TEENY to MT

[Fugu ME100]

Hi Greg

TS-DOS is not needed to re-flash the REX.  Teeny should be good enough to
get the RF149.co across to the model T.  The flash program has its own
built in DOS which should them pull in the two other ROM files from the
ŒmComm Drive¹. Make sure tsd100.bx and RXF149.BR are at the top level of
the virtual drive, these are the TS-DOS and REXMGR ROMs respectively. That
should be all you need :)

There are no diagnostics with RF149.co it will just wipe and reprogram the
REX.  The only times I have seen the REX lose its mind is when there are
power issues with the model T like a sudden glitch.  It is quite sensitive
to power problems. 

If you get really stuck please contact me offline and I am quite happy to
re-flash it for you.



On 22/1/19, 7:23 PM, "M100 on behalf of Greg Swallow"
 wrote:

>From what I can tell the spacing et al of the Rex is the same as the SR.
>The PCB of the Rex is thinner material than the SR, but the top surface
>of both is level/even when the two are set next to each other. I have
>made some adjusting attempts with near same result. Even installed the
>Rex in one of my other MT and had the same issue there.
>
>I was trying to load TS-DOS injected via mComm 2.5, but that is giving me
>an OD, Out of Data, error in line 5. It's my hope that the rf149.co might
>have enough "diagnosis" that it can tell if the Rex is
>in/programmed/whatever to further figure out what is wrong. Sill looking
>for a way to load TS-DOS, anyone have a suggestion?
>
>God Bless,
>
>Greg

Re: [M100] M100 stuck on the menu with weird date :o(

[Fugu ME100]

Wow that is really corroded,  I would replace it.

Simply heating the pins of the clock IC and using some new solder would be
a good start.

Not sure about caps in Australia hopefully someone local can help out with
that question. 

On 9/1/19, 5:23 AM, "M100 on behalf of Eric LK"
 wrote:

>Fugu ME100 wrote:
>> Do you have a picture of the thermistor?
>
>I just put a few closeup pictures here:
>https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fpics.lefa
>uve.org%2FTH1%2Fdata=02%7C01%7C%7C77f4209c462a891a08d67635bb39%7C
>84df9e7fe9f640afb435%7C1%7C0%7C636826370477369665sdata=XA
>bOMFV4SgM%2B6nnS56p59fHKwMBcwkK%2B1KZvDTozyCY%3Dreserved=0
>I also added a picture of TH2 for comparison (that's supposed to be
>the same component) and a few pictures of the RTC (they really didn't
>put that much solder for this IC :o) )
>
>

Re: [M100] another m100 failure (maybe cap? maybe not?)

[Fugu ME100]

Did you check the Vee voltage?  It should be close to -5V.

What you describe sounds very much like a failing -5V rail.  But need to
confirm with the Vee measurement.  It might be time to replace the
capacitors :(



On 7/1/19, 11:17 AM, "M100 on behalf of Jim Anderson"
 wrote:

>So, I had a VEE problem a while back, and I haven't got around to
>replacing the caps on that motherboard yet.  I pulled the board from a
>parts machine which I'd already cannibalized for its LCD and keyboard,
>and swapped it into mine.  (Actually, I didn't even bother pulling the
>board, I just put the bottom half of the parts machine together with the
>top half of 'my' machine.)
>
>Anyhow.  That was fine, for a while, but last week I pulled it out to
>show a relative over the holidays, and within seconds of turning the
>power switch on the LCD started to fade, as though someone was turning
>the contrast knob down.  I turned the contrast knob up a bit and got the
>display back, but it continued to slowly fade and I continued to chase it
>with the contrast knob until I hit the end of travel, then sadly watched
>it fade to total blankness.
>
>The machine still works in the sense that I can turn it on and get a beep
>from the BEEP command in BASIC, but the display is totally blank.
>
>Is this likely to be another (different) bad capacitor on the motherboard
>I'm using now, or is this likely to be something on the LCD board itself?
> Ie. If I replace the caps on my original motherboard and swap it back
>in, am I likely to still have a blank display?
>
>
>
>
>
>
>
>jim
>

Re: [M100] M100 stuck on the menu with weird date :o(

[Fugu ME100]

The +5V looks good, the -5V is a bit low it would be better in the -4.9V
to -5.1V region. That should go up when the caps are replaced.

It sounds like there is a bad joint somewhere on the board.

I think most Model T owners have more than one unit :-D


On 7/1/19, 7:48 AM, "M100 on behalf of Eric LK"
 wrote:



>Here are a few replies to the comments you guys sent me:
>VDD and VEE were respectively 5.06 and -4.62V I'm not sure -4.62 can
>qualify as a "strong -5V" but I'm really out of my experience zone
>here.

Re: [M100] M100 stuck on the menu with weird date :o(

[Fugu ME100]

If fixing the board voltages does not remove the problem the next issue could 
be dry joints near the clock chip,  at least on two machines I repaired that 
was the problem.   It looks like the clock chip was placed as a second op when 
the boards were made and the soldering was not very good.  In one case it was a 
cracked joint near the clock chip and the other was just a really bad joint 
that had failed over time – there was a hole without any solder.Simply 
pressing down on the clock chip area allowed the board to work properly.

The fact, in this case, the keyboard does not work seems to indicate that the 
area near the keyboard connector has problems.  The clock chip happens to be in 
that section of the board too.  When the unit is closed the keyboard cables 
press down quite hard on the board and it does flex very slightly.  So an open 
unit might work and the close unit does not – that’s how I found the issue the 
first time :)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, January 6, 2019 at 7:44 AM
To: "m...@bitchin100.com" 
mailto:m...@bitchin100.com>>
Subject: [M100] M100 stuck on the menu with weird date :o(

I have at least one machine with this type of error.  Would be great to figure 
out what has to break for that to occur.


On Sun, Jan 6, 2019 at 8:37 AM Eric LK 
mailto:tr...@lefauve.org>> wrote:
Hi,

I'm still waiting for my replacement Ni-Cad battery but I've been
continuing using my M100 without any other issue... until tonight.

When I turned it on, the "low battery" light was on, and the date
displayed on the first line was wrong: ◥5ÿ 00,1919 Sun 00:00:00
I switched it off and on again, and it stayed this way. That's when I
noticed the keyboard wasn't responsive. Also the first 3 characters
flash every now and then (here is a 11 seconds video:
https://www.youtube.com/watch?v=jjUw2XpB0Gw
 ; it happens around 00:03)

I verified the voltage of the AA batteries and found 5.9V. Should be
OK but I still changed them.
Now the first line displays something like this: ros ??,1920 ñ)s ??:??:??
...and the keyboard is still non-responsive

I tried the reset button, which had no effect (the computer restarts
in the same state), and the whole reset (Ctrl+Break+Reset), which
removed all files from the ram filesystem but it's still stuck.

After a quick look inside, the Ni-Cad battery didn't seem to have
started to leak, and I measured about 4.9V to its pins; I also noted a
faint buzzing sound coming from the LCD area while it was open.

I also tried to switch the "memory power" switch off, remove the
batteries, replace the batteries, switch everything on again... same
result.

At this point, I'm out of ideas... Any suggestion about how to
diagnose and fix this problem?

Eric

PS: There is a kind of battery leak damage around a screw on the
motherboard, but it's nowhere near any battery (it's located on the
left of the power switch). I noticed it when I first opened it a few
days ago, and I planned to give it a clean with isopropyl Alcohol when
I'll change the Ni-Cad but I didn't touch it yet. Could it be related
to today issue? Here is a picture :
http://pics.lefauve.org/20-32-45.jpg

Re: [M100] M100 stuck on the menu with weird date :o(

[Fugu ME100]

A quick check is to measure the voltages at the VDD and VEE test points
marked on the motherboard, they should be a strong +5V and -5V
respectively.  From the fault you are reporting it sounds as if the main
motherboard voltages are bad.  The NiCd should be about 3.7V when the
power is off.   The ‘corrosion’ looks like damage from leaking
electrolytic capacitors - very typical for the Model T and any old/vintage
equipment. 

The next step looks like replacing all the electrolytic caps on the board
as well as the NiCd.  Fortunately ….. there is a video on YouTube on how
to replace them by Jeff Birt (the link has been posted on the forum but I
could not find it), that should help with the replacement :-)

I have seen this behavior quite a few times, on old Model 100s in
particular, the first step is to get the motherboard voltages clean and
stable.  There may also be broken/cracked solder joints on the board that
need to be repaired later - the PCB build quality was not the best. :(
The faint buzzing sound is possibly the DC/DC power transformer
overloading for some reason.




On 6/1/19, 5:37 AM, "M100 on behalf of Eric LK"
 wrote:

>Hi,
>
>I'm still waiting for my replacement Ni-Cad battery but I've been
>continuing using my M100 without any other issue... until tonight.
>
>When I turned it on, the "low battery" light was on, and the date
>displayed on the first line was wrong: ◥5ÿ 00,1919 Sun 00:00:00
>I switched it off and on again, and it stayed this way. That's when I
>noticed the keyboard wasn't responsive. Also the first 3 characters
>flash every now and then (here is a 11 seconds video:
>https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.yout
>ube.com%2Fwatch%3Fv%3DjjUw2XpB0Gwdata=02%7C01%7C%7Cb1a46fe150a94d4e06
>9508d673dc2a57%7C84df9e7fe9f640afb435%7C1%7C0%7C63682378676931
>1870sdata=TM%2B7eX8tPEbOMq67EjWHp8Y%2BEaa4xJv1LSkKFzoGS%2BM%3Dre
>served=0 ; it happens around 00:03)
>
>I verified the voltage of the AA batteries and found 5.9V. Should be
>OK but I still changed them.
>Now the first line displays something like this: ros ??,1920 ñ)s ??:??:??
>...and the keyboard is still non-responsive
>
>I tried the reset button, which had no effect (the computer restarts
>in the same state), and the whole reset (Ctrl+Break+Reset), which
>removed all files from the ram filesystem but it's still stuck.
>
>After a quick look inside, the Ni-Cad battery didn't seem to have
>started to leak, and I measured about 4.9V to its pins; I also noted a
>faint buzzing sound coming from the LCD area while it was open.
>
>I also tried to switch the "memory power" switch off, remove the
>batteries, replace the batteries, switch everything on again... same
>result.
>
>At this point, I'm out of ideas... Any suggestion about how to
>diagnose and fix this problem?
>
>Eric
>
>PS: There is a kind of battery leak damage around a screw on the
>motherboard, but it's nowhere near any battery (it's located on the
>left of the power switch). I noticed it when I first opened it a few
>days ago, and I planned to give it a clean with isopropyl Alcohol when
>I'll change the Ni-Cad but I didn't touch it yet. Could it be related
>to today issue? Here is a picture :
>https://eur04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fpics.lefa
>uve.org%2F20-32-45.jpgdata=02%7C01%7C%7Cb1a46fe150a94d4e069508d673dc2
>a57%7C84df9e7fe9f640afb435%7C1%7C0%7C636823786769311870sd
>ata=Mrq3ifSaeZdGkCk8imGPxQqDsg3fDTxsBdgV%2BV2OiEE%3Dreserved=0

Re: [M100] TPDD 2 request for info

[Fugu ME100]

Took a look at the TPDD2 DC/DC convertor schematic in the Manual (Pg 36), the 
convertor is very similar in operation to that in the Model T.  There could be 
a number of problems that are causing the hot transformer:

The DC/DC convertor is isolated from everything else when it is being powered 
for your testing?

 - The output caps (C9 & C10) could be short circuit causing an overload on the 
the output (as you indicated).  However “generally" low voltage caps will fail 
open circuit as their contents leak.  It might be worth simply replacing them 
as a matter of good refurbishment practice.  Have you tried a continuity test 
between pins 3 and 1 of P3 with the power off?  There is a rectifying diode in 
the circuit so the measurements should be OK.  What is the voltage across the 
pins when it is powered on?
- The input to the transformer T1 also has two caps (C5 & C6) they could be 
replaced although they should not impact the transformer, they are acting as 
part of a filter.
- The transformer itself might be damaged internally causing it to simply heat 
up when power is applied.  Windings shorted/breakdown of the insulation etc.
- Q6 or Q7 might of failed so that they no longer form an oscillator to the 
winding of T1.  In which case the windings would simply act as a heater with a 
DC voltage.

There are modern power modules that can be used to replace the 
T1/Q6/Q7/Capacitor chain if needed so it is probably still repairable, although 
the drive PCB might have its own issues.  I have successfully used a DC/DC 
module on a Model T102 that had severe battery leak damage and corroded DC/DC 
parts.

I could not access the pictures they require a login.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Charles Hudson mailto:clh...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, January 4, 2019 at 6:29 AM
To: mailto:m100@lists.bitchin100.com>>
Subject: [M100] TPDD 2 request for info


I have determined that the power input is capable of supplying about 6VDC to 
the board when powered by a set of four fresh AA alkalines, and about 7 VDC 
from a TRS power adapter, aka "wall wart".

With the adapter supplying power and with the cable to the drive PCB 
disconnected - in other words, with little or no load to drive - I find that 
the transformer T1 gets very hot; too hot to touch after a minute or two with 
the power switch in the "on" position. The transistor next to the transformer 
gets hot as well, though not as much as T1. Neither component heats up unless 
the power switch is "on".

I'm not much of an EE but it seems to me that the likely explanation for this 
phenomenon is that some other component - maybe a capacitor? - has become a 
dead short, causing the transformer to run at capacity.

Another possible explanation might be that the two input leads to the board 
have at some time been switched, causing a reversal of polarity. This occurs to 
me because for both the batteries and the adapter the red wire shows negative 
and the dark blue wire shows positive on my meter.

I'm hoping for some guidance from more knowledgeable readers in order to 
diagnose the problem further.  I have posted pictures on the VCFED at:

http://www.vcfed.org/forum/showthread.php?67685-TPDD2-Repair=551913#post551913

Thanks for your replies,

-CH-

[https://ipmcdn.avast.com/images/icons/icon-envelope-tick-green-avg-v1.png]
  Virus-free. 
www.avg.com

Re: [M100] Model 100 power adapter

[Fugu ME100]

I thought the Model T’s where center negative?  :)

The  T1133-P5N-ND Digikey 6V 1A power supply seems to work well as a 
replacement.

Most of the ‘brick’ supplies cannot be easily repaired best to seek out a new 
one.   Check that the output is 6V using a voltmeter if not then the supply is 
dead.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Kurt McCullum mailto:ku...@fastmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, December 17, 2018 at 6:47 PM
To: mailto:m100@lists.bitchin100.com>>
Subject: Re: [M100] Model 100 power adapter

I have had good luck using power supplies for TI calculators. They seem to have 
the right plug and most are center positive.

Kurt


On Mon, Dec 17, 2018, at 3:42 PM, gotoole wrote:
Hi All

I have 2 Power adapters for my model 100 both are now not working.

Is their anything I can check to see why they are not working and is it 
possible to get a replacement ?

Regards

Gordon



Sent from my Samsung Galaxy smartphone.

Re: [M100] Building a run of TPDD cables using Rick's design

[Fugu ME100]

I plan to build one hopefully to confirm (or not) that my TPDD drive is OK
and the original cable is bad.  The drive gives intermittent results which
I think might be related to a bad cable or connector - it could be the
header on the drive PCB. Hoping this cable will provide the necessary
answers.  As well as test out the design.

If it works I might build up the other two OSH Boards so with your cables
should be able to bring some TPDDs back into service :)

All the parts are here just need some free hours to build and test the
cable.  

On 28/11/18, 8:18 AM, "M100 on behalf of Josh Malone"

wrote:

>All,
>
>I've had a couple people express interest in having me build them a
>TPDD cable based on Rick's PCB from oshpark. I'm still sourcing parts,
>but I figured if I could get more people interested I could get the
>price down. I'm trying to figure out a housing option that allows use
>with the M100 without a port extender, though I could just bundle a
>cheap port saver for a few more $.
>
>I haven't costed this project out yet, so I'm conservatively asserting
>that I can do it under $20ea. Just gauging interest right now.
>
>Also, if someone else is already building these, please let me know --
>I don't want to duplicate effort here.
>
>Thanks,
>
>-Josh

Re: [M100] project updates.

[Fugu ME100]

I have partial disassembly for the DVIs own code (only enough to understand 
what it was doing) and disassembly for the T’s boot code.  I will send them off 
line.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, November 23, 2018 at 8:46 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] project updates.

interesting.  do you have a disassembly?

On Fri, Nov 23, 2018 at 11:27 AM Fugu ME100 
mailto:b4me...@hotmail.com>> wrote:
The I2C serial EEPROM will need to hold the M100/T102/T200 boot code, M100/T102 
Disk BASIC Code and the T200 disk BASIC code (2 parts) which is probably not a 
lot of bytes by todays standards :-)  The Disk BASIC also goes out to read the 
version info from the DVIs own boot code which is an interesting twist, it 
requests the specific sector where the version info is located.  As all the 
sector locations are fixed they are very easy to intercept.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, November 23, 2018 at 6:05 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] project updates.

update:
I received my MTVGA PCBs yesterday and have built one up.  So far so good, 
powers up like it should.
I've been reverse engineering the DVI, and I've decided to try and make this 
100% compatible with DVI meaning the M100 will auto-detect it's presence, and 
MTVGA will auto-load and install the DVI software that originally came with 
DVI.  This requires the ability for MTVGA to store and deliver to the M100 the 
needed DVI software.  Plan is to use I2C serial eeprom for that.

Re: [M100] project updates.

[Fugu ME100]

The I2C serial EEPROM will need to hold the M100/T102/T200 boot code, M100/T102 
Disk BASIC Code and the T200 disk BASIC code (2 parts) which is probably not a 
lot of bytes by todays standards :-)  The Disk BASIC also goes out to read the 
version info from the DVIs own boot code which is an interesting twist, it 
requests the specific sector where the version info is located.  As all the 
sector locations are fixed they are very easy to intercept.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Stephen Adolph mailto:twospru...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, November 23, 2018 at 6:05 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] project updates.

update:
I received my MTVGA PCBs yesterday and have built one up.  So far so good, 
powers up like it should.
I've been reverse engineering the DVI, and I've decided to try and make this 
100% compatible with DVI meaning the M100 will auto-detect it's presence, and 
MTVGA will auto-load and install the DVI software that originally came with 
DVI.  This requires the ability for MTVGA to store and deliver to the M100 the 
needed DVI software.  Plan is to use I2C serial eeprom for that.

Re: [M100] M100 dead - looking for causes of low VEE

[Fugu ME100]

Low Vee is most likely caused by bad caps on the -5V line.  The loss of
-5V after a few seconds is a typical symptom as is the common problem of
the LCD fading in and out over time.

If you replace the -5V caps it should bring the machine back to life.  I
would also suggest replacing all the caps while you have the unit open.

Just checked, C85 and C86 are the two to look at they may have some local
corrosion near/under them which is a good visual indicator of bad caps.



On 22/11/18, 10:51 PM, "M100 on behalf of Jim Anderson"
 wrote:

>Hi,
>
>A couple of weeks ago my beloved M100 dropped dead in the midst of using
>it (I've been keeping a journal).  Suffice to say that I was already
>writing about something unhappy at the time and the death of the M100 was
>sort of the emotional icing on the cake.  I only got as far as observing
>the following before putting it aside for the night in frustration:
>
>- AA batteries are good (also tried with external DC input)
>- Low Battery LED isn't on, and flickers as expected when I cycle the
>power switch
>- LCD screen is totally blank, doesn't even darken when turning contrast
>knob
>- Beep test in BASIC doesn't work
>
>I had a chance to take another stab at it tonight and lo, it worked when
>I put batteries back in it, but promptly died again about ten or fifteen
>seconds after powering it on.
>
>VDD and VB are both good, but VEE is -1.4V rather than the expected -5V.
>I thought I'd post here to see if anybody has any pointers on a common
>culprit for low VEE before I start digging deeper (which is a project for
>another evening).  I have a funny feeling I've read about someone else
>having a low VEE problem, but searching the list messages turned up
>nothing for me. 
>
>
>
>
>
>
>
>jim
>

Re: [M100] Tandy Model 100

[Fugu ME100]

Hi

The failure you describe is not one I have seen.  The two LCDs that failed
in my machines had horizontal bars of slightly darker contrast.  When the
contrast was varied the bars remained slightly darker than the rest of the
screen.  Eventually the -5V dropped to -2V as I assume the current draw
exceeded the power supply limits.  In both cases it appeared the
horizontal driver chip was bad and could not properly drive the LCD or
perhaps the LCD itself was bad.  Hard to tell but replacing the LCD module
with another one fixed the problem.

The fact you need to power cycle the unit, not just press reset, could
mean there is a power supply issue on the motherboard.As the contrast
is changed the LCD driver chips might be seeing the supply voltages drop
causing erratic behavior.   May want to check that the cable to the screen
is good and has no bad joints at the LCD module side?  Could be a simple
dry joint on the cable connection.

On 14/10/18, 8:22 AM, "M100 on behalf of Rafael Arena"

wrote:

>Hi!
>
>Yeah, everything seems stable on the +-5v side. I will try to replace all
>the caps.  But probably the screen is going bad :(
>
>Thank you,
>
>> 
>> 
 
 
>> 
>> 

Re: [M100] Tandy Model 100

[Fugu ME100]

Hi

If the voltage change on pin 4 is smooth the voltages look right - pg 38
of the M100 reference manual gives 0-4V as the range for V2.  It feels
like VR1 is working correctly, indeed the whole contrast circuit would
appear to be fine. 

With the screen plugged in can you measure the -5V and +5V voltages at
their respective test points.  They should remain stable as the contrast
is changed.  Also check the reset line to the LCD, it is pin 7.

It is quite tricky to test with the screen plugged in, the only way I have
been able to do that is to take the screen out to get at the connector
pins.  

Although it may appear good the -5V supply could still have problems due
to bad caps.  Similarly the +5V could be bad too because of bad caps.  It
sounds  more like a power supply issue having to power cycle to make
things work properly.  If one cap has been replaced I would probably just
replace all the power supply related caps.  The 10uF caps always seem to
be dried up when I have had power supply issues.

It could also just be a bad screen they do fail themselves due to age :(
  

On 14/10/18, 3:53 AM, "M100 on behalf of Rafael Arena"

wrote:

>Hi!
>
>I tried what was suggested and I get 0-3.8v on pin four (without the
>screen plugged in).  Can’t seem to figure out how to measure pin 4 with
>the screen plugged in.  When i turn the contrast knob the screen starts
>to jump around the display random line sporadically.  I have to turn the
>computer on and off a few times in order to get it to come on.
>
>Thank you,
>
>> On Oct 12, 2018, at 11:57 AM, Fugu ME100  wrote:
>> 
>> Hi
>> 
>> The voltages look good.  I usually replace C86 too it is part of the -5V
>> output circuit. 
>> 
>> You could try measuring the contrast voltage on the connector, pin 4,
>>see
>> if it smoothly transitions and there are no “jumps".  Also check the -5V
>> is stable as you vary the contrast.  I have noticed on some screens that
>> are failing the -5V will drop to -2V as the screen draws too much
>>current
>> as the contrast is varied.
>> 
>> If the contrast voltage is not a smooth change then you could try
>>Brian’s
>> suggestion to clean VR1.
>> 
>> Is it always missing a few lines on the screen?  Do the missing lines
>>have
>> a pattern?  
>> 
>> On 12/10/18, 2:35 AM, "M100 on behalf of Rafael Arena"
>> 
>> wrote:
>> 
>>> Hi,
>>> 
>>> At times the computer comes on and when adjusting the screen display
>>>the
>>> image gets all distorted and then fades away.  I have checked the +5
>>>and
>>> -5 volts that the screen needs and I get +5 and -4.8 volts
>>>respectively.
>>> I changed capaciitor ‘C85’ and checked all the memory chips.  Like I
>>>said
>>> it works every now and again, missing a few lines on the screen.  When
>>>i
>>> play with the contrast knob the image distorts and some times fades
>>>away.
>>> Any of this makes sense? Lol
>>> 
>>> Thank you,
>>> 
>>>> On Oct 11, 2018, at 10:27 PM, Fugu ME100  wrote:
>>>> 
>>>> Hi 
>>>> 
>>>> What are the symptoms you are experiencing?
>>>> 
>>>> VR1 could go bad but it could also be due to oxidation on the
>>>>resistors
>>>> tracks.  People have tried to use contact cleaner to revive them.
>>>>Might
>>>> be worth looking into trying that option first?
>>>> 
>>>> 
>>>> On 11/10/18, 3:57 PM, "M100 on behalf of Rafael Arena"
>>>> >>>minikni...@hotmail.com>
>>>> wrote:
>>>> 
>>>>> Hello,
>>>>> 
>>>>> I have a semi functional Model 100.  I believe the issue is with the
>>>>> variable resistor ŒVR1¹.  Where can I get a replacement?  Do those
>>>>>VR¹s
>>>>> typically go bad?
>>>>> 
>>>>> Thank you,
>>>> 
>>>> 
>> 
>> 

Re: [M100] Tandy Model 100

[Fugu ME100]

Hi

The voltages look good.  I usually replace C86 too it is part of the -5V
output circuit.  

You could try measuring the contrast voltage on the connector, pin 4, see
if it smoothly transitions and there are no “jumps".  Also check the -5V
is stable as you vary the contrast.  I have noticed on some screens that
are failing the -5V will drop to -2V as the screen draws too much current
as the contrast is varied.

If the contrast voltage is not a smooth change then you could try Brian’s
suggestion to clean VR1.

Is it always missing a few lines on the screen?  Do the missing lines have
a pattern?  

On 12/10/18, 2:35 AM, "M100 on behalf of Rafael Arena"

wrote:

>Hi,
>
>At times the computer comes on and when adjusting the screen display the
>image gets all distorted and then fades away.  I have checked the +5 and
>-5 volts that the screen needs and I get +5 and -4.8 volts respectively.
>I changed capaciitor ‘C85’ and checked all the memory chips.  Like I said
>it works every now and again, missing a few lines on the screen.  When i
>play with the contrast knob the image distorts and some times fades away.
> Any of this makes sense? Lol
>
>Thank you,
>
>> On Oct 11, 2018, at 10:27 PM, Fugu ME100  wrote:
>> 
>> Hi 
>> 
>> What are the symptoms you are experiencing?
>> 
>> VR1 could go bad but it could also be due to oxidation on the resistors
>> tracks.  People have tried to use contact cleaner to revive them.  Might
>> be worth looking into trying that option first?
>> 
>> 
>> On 11/10/18, 3:57 PM, "M100 on behalf of Rafael Arena"
>> 
>> wrote:
>> 
>>> Hello,
>>> 
>>> I have a semi functional Model 100.  I believe the issue is with the
>>> variable resistor ŒVR1¹.  Where can I get a replacement?  Do those VR¹s
>>> typically go bad?
>>> 
>>> Thank you,
>> 
>> 

Re: [M100] Tandy Model 100

[Fugu ME100]

Hi 

What are the symptoms you are experiencing?

VR1 could go bad but it could also be due to oxidation on the resistors
tracks.  People have tried to use contact cleaner to revive them.  Might
be worth looking into trying that option first?


On 11/10/18, 3:57 PM, "M100 on behalf of Rafael Arena"

wrote:

>Hello,
>
>I have a semi functional Model 100.  I believe the issue is with the
>variable resistor ŒVR1¹.  Where can I get a replacement?  Do those VR¹s
>typically go bad?
>
>Thank you,

Re: [M100] Screen Flickering?

[Fugu ME100]

Can you check your –5V rail?  It should be a solid –5V +/- a few %.Might 
also want to check the +5V rail.   If the –5V is low or is very unstable then……

It is most likely due bad electrolytic caps.  The contrast on the screen is 
controlled by the –5V.

Unfortunately the caps will need to be replaced on the –5V rail – I think they 
are C85 and C86.Probably should replace all the electrolytics too while 
working on the machine.  If you take a look around the base of the caps you 
might see some residue or corrosion around the base of the caps.

Overtime it will fail completely and the screen will  go blank.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Roger Mullins mailto:km4...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, September 29, 2018 at 9:13 PM
To: mailto:m...@bitchin100.com>>
Subject: [M100] Screen Flickering?

Hi all-

Anything in particular I can do to fix a flickering display? It's just started 
happening. It was doing it on an AC adapter so I unhooked that and put in four 
fresh AAs, but it kept doing it. I did open it up and checked the movement on 
the contrast knob and that seemed fine. I'm just wondering if there's anything 
I can do or if I'm on my way out with yet another LCD.

Here's a short YT video of what I'm seeing.

https://youtu.be/GwBds7YdAJk

Thanks!
Roger

Re: [M100] New Age Digital Storage Box (NADSBox)

[Fugu ME100]

Using the Arduino IDE the F() macro or equivalent is essential to store text 
strings otherwise you will run out of RAM fast.

The SD-Card Library that is part of the IDE is a memory hog too.It does not 
work well on the smaller ATMEGA parts with only 2K of memory especially if you 
want to add lots of other code around it.


So, I guess it still can't be really working fully with 2318 bytes used out of 
2048! even though at least it gets through setup(), and loop() loops, and 
Serial works again.
Aside from reducing ram usage by just removing stuff, I guess I now care about 
tricks like the F() macro which compiles static data into flash rather than ram.

bkw

Re: [M100] DVI or modern equivalent

[Fugu ME100]

Here are my thoughts on the DVI :)

All you really need is the service manual and user manual, the DVI
operation is easy to reverse engineer from those two documents.  The ŒZ80¹
DVI code is actually on the DVI boot disk.  When the DVI powers on it
boots from the floppy disk to load the operational code. The 1K P-ROM on
the DVI only contains the init code and boot code (I think) to load
pre-assigned floppy sectors, the other ROMs are associated with the
character/CRT control.  There are another set of sectors on the DVI boot
disk that contain the disk BASIC for the 100/102 and others that are used
for the T200.  The 100/102 and 200 boot slightly differently due the T200
RAM bank structure I believe.  However this is taken care of by the boot
process itself and not really an issue.

The CRT is driven by a CRTC controller chip that has 2K of RAM associated
with it - just character based, hence the character generation ROM.  The
FDC is a really simple floppy controller it does very little the Z80
processor does the majority of the work formatting the sector to write to
the floppy.  It also does the extraction of the sector data from the bits
read from the floppy disk.

The interface to the DVI is a simple Œmail box¹ that is based on the 8255
PPI chip, Mode 1 operation if memory serves.  Basically the Model T writes
a control byte to the PPI which causes an interrupt to the DVI CPU.  The
DVI CPU will then perform whatever action is commanded based on the data
written to the mail box.  The model T polls the PPI waiting for data to
come back from the DVI box to either say the command was successful or
deliver the requested data.

The mailbox control commands are in the service manual as is the exact
mailbox protocol.  The only difficult part is building a 5V-to-3V level
shifter to interface to modern hardware such as the PI, but there are
bi-directional Œ245 and Œ244 chips that are available.   The PI would have
to deal with sector based access in order to boot the disk BASIC needed to
control the DVI but that is quite easy to do.

I did partly disassemble the DVI Z80 code if anyone would like it, just
let me know off line - please no sniggering at my efforts :-D   The code
is pretty much spaghetti, parts are quite simple to follow but then the
FDC code gets very involved.  I personally feel it leads you down a rabbit
hole that does not really help except to confirm what is already available
in the two documents.

Based on all this information I built a PIC 32MX based DVI emulator that
could read SD-Card based Œvirtual¹ floppy disks (to boot) and output 3-bit
VGA characters and graphics.  It is about 80-90% complete but then I had
to move so it is all packed away in storage at the moment.  It did need
some extensions to the Model T to allow selection of the Œvirtual¹ disk
and to configure some things on the board which was to be the next step.
Although this could (and is now) done using BASIC print statements.

Just my 2c worth. :)


On 13/9/18, 6:53 AM, "M100 on behalf of Greg Swallow"
 wrote:

>Here here! With all the talk about a PI or TEENSY as TPDD, why not do
>something that duplicates the code in the DVI. The DVI is a Z80 after
>all; right? Seems a PI or some such single board CPU would make a good
>candidate to make a modern DVI. My EPROM programmer is shot so I can't
>pull the ROM and snatch a copy. Is there a source for at least the DVI
>protocol? More than say the DVI Service manual?
>
>God bless,
>GregS <><
>
>
>- Original Message -
>From: "James Zeun" 
>To: m...@bitchin100.com
>Sent: Thursday, September 13, 2018 3:58:02 AM
>Subject: [M100] DVI or modern equivalent
>
>Hey everyone!
>
>We discussed this a while back but I'm not sure if anything any was said
>on
>video output.
>
>At present is there any way I can output the M100's screen to a monitor?
>Akin to how the original DVI did?
>
>Cheers

Re: [M100] Tandy 200 RAM modules

[Fugu ME100]

There is also a single RAM version with an easier to solder SOIC part.
https://oshpark.com/shared_projects/naMPAS3A

They do come and go from eBay, just need to look out for them.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Brian White mailto:bw.al...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Sunday, August 26, 2018 at 7:32 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Tandy 200 RAM modules

I don't know about pre-made, but there is one you can build yourself:
Here's links to the pcb on oshpark and a pre-loaded digikey cart.
http://tandy.wiki/Model_200_RAM

On Sun, Aug 26, 2018 at 10:18 AM Josh Malone 
mailto:josh.mal...@gmail.com>> wrote:
Hi all,

Is there any current source for Tandy 200 24k RAM modules? My T200
only has a single RAM bank. I feel like I used to see these all the
time on eBay, but a search just now turns up nothing.

Thanks,

-Josh


--
bkw

Re: [M100] New Age Digital Storage Box (NADSBox)

[Fugu ME100]

That sounds great.   What sort of current draw are you getting?  Quite curious.


From: M100  on behalf of Brian White 

Sent: Friday, August 24, 2018 20:12
To: m...@bitchin100.com
Subject: Re: [M100] New Age Digital Storage Box (NADSBox)

I was playing with the Teensy 3.6 some more last night and got it waiting & 
responding to commands by serial (the built-in ftdi usb-serial not via max232 
yet), reading/writing to files in a fat32 fs on the sd, blinking the on-board 
led during drive activity, and displaying text on a tiny 128x64 0.96 inch oled 
display via i2c.

All while sitting at a counter at a diner.

Because it didn't need anything but a laptop, usb cable, and the chip stuck on 
the end of the cable, and 4 jumper wires just for the oled display which was 
just for play anyway, probably wouldn't actually want that on the finished 
device.

These arduino libraries and built in examples make it all pretty easy to get 
started.

And teensy has an rtc built-in too. Needs another battery, but a cr2032 can 
apparantly keep the rtc going for about 17 years, so, not a problem.

This 32 bit 180mhz cpu is overkill, but it's just handy having the sd card 
reader and usb port already built in. The cpu can be underclocked in software 
but I don't know if it goes all the way down to 4!

Re: [M100] New Age Digital Storage Box (NADSBox)

[Fugu ME100]

At least for an ATMEL MEGA not much power at all especially if it is run at 
4MHz.  The biggest rated current draw on the TPDD emulator is the SD card which 
is spec’d at around 100mA while writing to the flash,  but is a little 
manufacturer dependent some are better than others.   The TPDD emulator can 
also be put to sleep when idle which reduces the overall power drain to the uA 
region or lower depending on the sleep level.  So with a single no name AA and 
taking into account inefficiencies in the power supply chain you could 
theoretically run the system continuously for about 10 hours.  By sleeping the 
MEGA/TPDD when it was not being used that time could extend out to days if not 
weeks.   The sleep is also useful if you forget to switch off the board when 
done :)

I am sure the other processors could also be put to sleep if the right 
hardware/pins were connected.  The latest generation of embedded MCUs have 
really low sleep currents if the board is built correctly, however most are 
poorly designed leading to high leakage currents.

As to the powerful CPU question in its day the DVI box ran a 4MHz Z80A 
compatible so could easily outperform the model T -  IMHO  :)  A 4MHz Mega 
seems quite in keeping with the original DVI, especially when it is the size of 
a AA battery……


From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of James Zeun mailto:james.z...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, August 24, 2018 at 4:31 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] New Age Digital Storage Box (NADSBox)

If you need power, how much are we talking? Could you not just use AA's? The 
TPDD uses 2xAA :-)

On Fri, 24 Aug 2018, 3:37 a.m. Brian White, 
mailto:bw.al...@gmail.com>> wrote:
That's what I would say if using an sbc (pi) instead of a microcontroller 
(arduino).
But even these microcontrollers are more powerful cpus and have more ram than 
the host machine in this case, but then again, ever since day one, peripherals 
have always had their own cpus that were at least the equivalent of the host if 
not more, especially disk drives, modems, and printers. So, no not really.

Re: [M100] I/O error with disk drive

[Fugu ME100]

Have you tried a cold boot of the model T?

The drive makes shows no activity at all?  No front light or spinning disk?

You could check the serial interface is good as you might of seen from Josh’s 
thread the serial port can and does fail.   If this is a TPPD-1 drive could 
also check the DIP switches are set correctly for boot.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Jesus R mailto:sonor...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, August 24, 2018 at 3:59 AM
To: mailto:m100@lists.bitchin100.com>>
Subject: [M100] I/O error with disk drive

Team, after placing a new belt on the Tandy portable disk drive I still get an 
error when trying to initialize it:

?ao error in 10 trs 80

It sits there and looks dead and is silent. I'll check the out of the power 
board next.

Re: [M100] Backup ROM

[Fugu ME100]

You could try this utility 
http://www.club100.org/memfiles/index.php?===Steve%20Adolph/ROM2S
  It will dump the ROM as an ASCII HEX file to a TPDD device.  There are online 
utilities that can convert it to a binary file that could be loaded into a REX. 
 I have used it to read mystery OPTROMs that sometimes come with the eBay 
machines.

However I believe some OPT ROMs have to be modified to work with the REX so the 
PSCG+ disk ‘might’ not work with the REX directly.

Alternatively the OPTROM may already have been converted into a REX file which 
is worthwhile checking.  There is a validated list of OPTROM images on 
http://bitchin100.com/wiki/index.php?title=REX  Others might exist just need to 
check the archives.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Rick Shear mailto:rdsh...@comcast.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Friday, August 10, 2018 at 3:20 AM
To: mailto:m100@lists.bitchin100.com>>
Subject: [M100] Backup ROM

I have a Model 100 with a PSCG Disk+ ROM in it.  I am in the process of 
gathering all the parts to build a REX board and would like to back up the 
Disk+ ROM to install on the REX.  I've been trying to find a utility to back 
the ROM up from the Model 100 to a TPDD device.  Is there such a program 
available?  Or will I have to get/build an eprom reader to get the image?

I found a program on club100 
(ARTROM.CO)
 that would read the image and send it to an eprom burner, but I don't have one 
of those devices and really don't need to burn a copy to an eprom.


Thanks for any pointers in the right direction.

Rick

Re: [M100] What would it take to build a modern DVI?

[Fugu ME100]

The DVI boot code could run on a Z80 emulator however it would be quite a lot 
of work and the DVI boot code is heavily intertwined with the CRTC and FDC 
chips as to make it a fruitless exercise.  The boot code on the DVI actually 
formats the sectors for the disk and simply uses the FDC to perform the analog 
functions.   Even for the CRT operations the code does a lot of VRAM 
manipulation to format the screen.  You would need to emulate those two chips 
very closely to make it work at which point you might as well start from 
scratch since you would want to use an SD-Card and either VGA or HDMI.  The 
mail box communications used by the model Ts on the DVI interface is quite 
primitive and very easy to implement, it is about 20 lines of C-code to get the 
interface talking, I think it is fewer lines of ML on the Model T :)

It is quite amazing what was achieved with so little memory by the designers of 
the Model T.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of you got me mailto:ven...@hotmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Wednesday, July 25, 2018 at 7:57 PM
To: Model 100 Discussion 
mailto:m100@lists.bitchin100.com>>
Subject: [M100] What would it take to build a modern DVI?


I'm barely into programming so I can't completely visualize how this would be 
done.

I'm thinking you would still need the m100/m102/m200 cable.


Then interface the cable to a USB i/o device like 
https://ameridroid.com/products/usb-io-board


The device connects to a modern computer that is running a Z80 emulator with 
CRT support like 
http://www.z80.info/z80emu.htm#EMU_CPU_PCDOS


Now, could the emulator work properly with the data from a copy of the DVI 
ROMs? I know one is bios and the other a character set?


Does someone have a binary file of the boot disk?

Re: [M100] Ask a silly question

[Fugu ME100]

I did reverse engineer around 60% of the boot code of the DVI last year to work 
out how the Video and Floppy were used – most of it is very low level interface 
software for the FDC chip and some spaghetti code to control the graphics chip. 
 Quite a lot of corners cut and some neat ways to deal with multiple interrupts 
on an Z80 is what I found -  I thought I knew how to write Z80 ML!

Then ported the interface logic to a PIC 32MX (at least in essence) to produce 
VGA output at 40x26 or 80x26,  with 3bit color if you wanted it.  The drives 
use an SD Card with virtual Floppies to allow support for all the features 
found in disk basic.   It runs all the diagnostics in the service manual and 
the user manual examples.   I did extend it to provide color with esc sequences 
and some basic graphics – however it is very crude at the moment using print 
chr$(27) + code.  The next step was to extend the disk basic with an overlay to 
take advantage of the enhanced capabilities.   At that point I ran into a 
terminated apt lease and have spent time looking for somewhere to live.  
Everything is in boxes now.

The board needs a respin to fix a power supply issue that will allow it to be 
properly powered from the model T.   It can be powered from USB at the moment 
with a virtual serial terminal.  It could be extended to mount the SD Card  as 
a mass storage unit on a PC then write to or extract from the virtual floppy.

As far as the model T is concerned it looks and runs like a DVI.  It has been 
tested on the 100, 102 and 200.  Oh and the cables do not need to be reversed :)

There are quite a few sections incomplete that are not part of the regular DVI: 
WiFi, Analog inputs, Keyboard and Sound, all of which would require disk basic 
extensions to be used successfully or at least some low level BASIC/MK code.   
However I am no longer sure about these as the RS232 port might be a better 
solution for WiFi and the keyboard/sound are beyond the DVI spec.

Anyway I will try to pick it up again once I have moved.

I decided not to use the PI at the time because I wanted to be able to plug 
this into the Model T and use it as a disk drive without the need to use a 
power brick or anything beyond the T and power supply.

If anyone has some good/interesting software to run on the DVI I would really 
appreciate access to test out the board. Thanks!

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of George Rimakis mailto:grima...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Wednesday, July 25, 2018 at 6:40 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] Ask a silly question

Has anyone managed to reverse engineer this DVI?

That would be a neat project.

~George

On Jul 25, 2018, at 9:30 PM, Randall Kindig 
mailto:randall.kin...@gmail.com>> wrote:

Thanks, Brian, that’s very helpful.

Randy
On Jul 25, 2018, at 1:12 AM, Brian White 
mailto:bw.al...@gmail.com>> wrote:

Randy I never answered your last question about the Model 200 cable.

It's these two items:

https://www.amazon.com/gp/aw/d/B003PU1EVG/

https://www.amazon.com/Connector-Rainbow-Ribbon-Cable-1-6ft/dp/B00XP54YKE/

These are just representative examples pulled up quickly from amazon on my 
phone. You can get the same things lots of different places including ebay and 
digikey etc.

That's it. You just stick the gender changer into one end and stick that end 
into the 102 or 200.

For polarity assurance, just keep the cable flat all the way to the computer.

That's it. No soldering, and the lack of polarity key on the computer end has 
an easy answer. And that cable works the same on both 102 and 200.

I mean it can buch up or fold or loop any way it wants once it's connected, but 
just imagine both the DVI and the computer are sitting on a table, with the 
back of the computer facing the front of the DVI, and both boxes are sitting 
right-side up on their feet. From that starting position, the cable travels 
from under the front of the DVI to the computer without twisting or folding 
over. Whichever side of the cable is the bottom at the dvi, is also the bottom 
at the computer. If it was a grey cable instead of tha rainbow one, you could 
write "bottom" & "top" or "up" & "down" right on the cable at the computer end 
with a sharpie, and that would be enough for even an unsuspecting future owner 
to get it right safely. The DVI end is polarity 

Re: [M100] tpdd mcomm setups

[Fugu ME100]

But I have a handful of REX modules.   Just contact me directly off list to 
arrange shipping.  :-)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Tom Dison mailto:fretina...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Monday, July 23, 2018 at 10:27 AM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] tpdd mcomm setups

Thanks so much!

On Mon, Jul 23, 2018, 12:20 PM Gregory McGill 
mailto:arcadeshop...@gmail.com>> wrote:
same place.. 
www.arcadeshopper.com/wp
  I'm temp out of stock but more are being made

On Mon, Jul 23, 2018 at 10:17 AM Tom Dison 
mailto:fretina...@gmail.com>> wrote:
And where do I find a Rex? I've really been looking but haven't found one.

On Mon, Jul 23, 2018, 12:14 PM Gregory McGill 
mailto:arcadeshop...@gmail.com>> wrote:
 you can push the ts-dos or teeny from the MCOMM using your tv set and the 
included remote to get the software there.. or get a REX and its got TS-dos 
included

On Mon, Jul 23, 2018 at 9:56 AM Tom Dison 
mailto:fretina...@gmail.com>> wrote:
So I don't need any software installed on my M200 for one of these? I have a 
TPDD but haven't been able to find a utility disk to use it.

On Mon, Jul 23, 2018, 10:56 AM Gregory McGill 
mailto:arcadeshop...@gmail.com>> wrote:
I am putting together a few MCOMM TPDD setups using android tv boxes, good 
rs232 cables and a null modem cable if anyone is interested they are in my 
store at 
https://www.arcadeshopper.com/wp

Greg

Re: [M100] Model 100 LCD doesn't work

[Fugu ME100]

OK great!

I think it is in the user manual 


From: M100  on behalf of Nathan Misner 

Sent: Sunday, July 22, 2018 00:01
To: m...@bitchin100.com
Subject: Re: [M100] Model 100 LCD doesn't work

Holy shit, thank you! The Ctrl+Break trick got it powering on! I thought my 
M100 was dead, but now it lives to see another day. I really wish Tandy had put 
that in the troubleshooting flowchart in the service manual, though.

-Nathan

Re: [M100] Model 100 LCD doesn't work

[Fugu ME100]

Swap the leads around on the meter :) the black wire to the -ve voltage and the 
red to gnd.


You could also try a cold boot, just in case.  Hold ctrl-break and power on.


The NiCd battery is in good health?



From: M100  on behalf of Nathan Misner 

Sent: Saturday, July 21, 2018 23:42
To: m...@bitchin100.com
Subject: Re: [M100] Model 100 LCD doesn't work

This is turning out to be "fun". The screen used to not do anything but after 
replacing my patch wire the screen is still blank (don't think it's black, only 
turns grayish when I push the contrast up all the way) but I'm able to 
manipulate the contrast and I'm no longer able to make the computer beep. I'm 
not really equipped to measure negative voltage (only have an analog meter), 
but VDD measures 5V and VEE makes the meter's needle go as left as possible, 
when before the patch wire it measured around +0.2 volts.

Re: [M100] SD2TPDD Project

[Fugu ME100]

The Teensy + USB dev card + SD Adaptor should work OK, but it may need a full 
RS232 I/F + driver.  The Arduino Mega is more than enough so should be fine on 
a Teensy.  I pushed it to an ESP12 which was fun :)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Lee Olivares mailto:l...@braains.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, July 21, 2018 at 3:16 PM
To: mailto:m...@bitchin100.com>>
Cc: mailto:m100@lists.bitchin100.com>>
Subject: Re: [M100] SD2TPDD Project

Nice work, I’ve been waiting for something to come along that would enable 
internal SD support ala uIEC on the C64.

I’ll have to see if a teensy plus an SD adapter would be the right combo for a 
compact setup, but I don’t see any conflicts right off the bat.

Cheers!

- Lee Olivares
- (909) 437-0250
- The Future or Bust.

On Jul 21, 2018, at 15:00, c646581 
mailto:c646...@gmail.com>> wrote:

Hello!

As several of you already know, I've been working on a TPDD emulator that runs 
on an Arduino Mega and uses an SD card for mass storage. I've gotten the 
emulator to the point where I feel comfortable releasing it for testing 
purposes.

Here is my GitHub page: 
https://github.com/TangentDelta/SD2TPDD

It's pretty limited at the moment. It doesn't support sub-directories or any of 
the expanded TPDD features. In the future, I hope to add more features to it!

Try it out and let me know how it goes!

Thanks,
Jimmy.

Re: [M100] SD2TPDD Project

[Fugu ME100]

It is a good set of tools that are very easy to navigate.  I have ported it to 
quite a few platforms now with excellent results.   It just works :)

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Lee Olivares mailto:l...@braains.net>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, July 21, 2018 at 3:21 PM
To: mailto:m...@bitchin100.com>>
Subject: Re: [M100] SD2TPDD Project

FatFS FTW; nice to see elm-chan come up, a prototyping wizard from outer-space, 
for those unfamiliar: 
https://youtu.be/i5MNLTc7YhY<https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fyoutu.be%2Fi5MNLTc7YhY=02%7C01%7C%7C8520cc7a24784a07629c08d5ef586408%7C84df9e7fe9f640afb435%7C1%7C0%7C636678085265205176=JxZ2i820N2kQdOUDCzmLoCi4gD59%2B203LGCRPUICoRk%3D=0>

- Lee Olivares
- (909) 437-0250
- The Future or Bust.

On Jul 21, 2018, at 15:18, Fugu ME100 
mailto:b4me...@hotmail.com>> wrote:

I used the FatFS 
http://elm-chan.org/fsw/ff/00index_e.html<https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Felm-chan.org%2Ffsw%2Fff%2F00index_e.html=02%7C01%7C%7C8520cc7a24784a07629c08d5ef586408%7C84df9e7fe9f640afb435%7C1%7C0%7C636678085265205176=ypQTpH%2B4JYtfipQeeeaTjLIaPvphHoyMsE%2F8n2NVSLA%3D=0>
 file system for the SD card,  it is much more flexible and avoids the nasty 
file and directory rename issues.  It will easily fit in a Mega – I think it 
was about 18K or less compiled.

The Arduino SD.h has a few bugs in it that have never been fixed including a 
really nasty size bug to do with sectors on the SD card.  Causes all sorts of 
problems when trying to size an SD card.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of c646581 mailto:c646...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, July 21, 2018 at 3:00 PM
To: mailto:m100@lists.bitchin100.com>>
Subject: [M100] SD2TPDD Project

Hello!

As several of you already know, I've been working on a TPDD emulator that runs 
on an Arduino Mega and uses an SD card for mass storage. I've gotten the 
emulator to the point where I feel comfortable releasing it for testing 
purposes.

Here is my GitHub page: 
https://github.com/TangentDelta/SD2TPDD<https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FTangentDelta%2FSD2TPDD=02%7C01%7C%7Ca9388d0753044e06a5c408d5ef557139%7C84df9e7fe9f640afb435%7C1%7C0%7C636678072598617205=K5taEgJbYvF%2FkSUv1QVxBLyyYoxj6xR7dF%2BmHMfqxNY%3D=0>

It's pretty limited at the moment. It doesn't support sub-directories or any of 
the expanded TPDD features. In the future, I hope to add more features to it!

Try it out and let me know how it goes!

Thanks,
Jimmy.

Re: [M100] SD2TPDD Project

[Fugu ME100]

I used the FatFS http://elm-chan.org/fsw/ff/00index_e.html file system for the 
SD card,  it is much more flexible and avoids the nasty file and directory 
rename issues.  It will easily fit in a Mega – I think it was about 18K or less 
compiled.

The Arduino SD.h has a few bugs in it that have never been fixed including a 
really nasty size bug to do with sectors on the SD card.  Causes all sorts of 
problems when trying to size an SD card.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of c646581 mailto:c646...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, July 21, 2018 at 3:00 PM
To: mailto:m100@lists.bitchin100.com>>
Subject: [M100] SD2TPDD Project

Hello!

As several of you already know, I've been working on a TPDD emulator that runs 
on an Arduino Mega and uses an SD card for mass storage. I've gotten the 
emulator to the point where I feel comfortable releasing it for testing 
purposes.

Here is my GitHub page: 
https://github.com/TangentDelta/SD2TPDD

It's pretty limited at the moment. It doesn't support sub-directories or any of 
the expanded TPDD features. In the future, I hope to add more features to it!

Try it out and let me know how it goes!

Thanks,
Jimmy.

Re: [M100] Model 100 LCD doesn't work

[Fugu ME100]

You may have already checked but make sure the –5V is good and that the 
contrast pot is working sometimes they do not work so the screen is in low 
contrast mode = not visible but still working.  You should be able to see the 
screen go almost entirely black as you turn the contrast pot or the menu might 
appear :)

Buzz out all the connections to the LCD header make sure no other trace has 
been damaged by a capacitor leak, it is possible to miss a break.   Make sure 
the connection onto the LCD is good and no corrosion has happened due to 
capacitors out gassing.   I have had a trace corrode under one of the caps that 
caused the screen to stop working.

The fact it beeps is a good sign it means the keyboard interface seems to be 
working, some of the same chips drive the LCD so they are probably good.

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Nathan Misner mailto:shicky...@gmail.com>>
Reply-To: mailto:m...@bitchin100.com>>
Date: Saturday, July 21, 2018 at 1:53 PM
To: mailto:m...@bitchin100.com>>
Subject: [M100] Model 100 LCD doesn't work

I'm having a problem with my TRS-80 Model 100 where the LCD doesn't function, 
but the computer is otherwise operating (if I type "beep" into BASIC, it works, 
etc.). I replaced all of the capacitors on the board that I had replacements 
for (everything but C103 and C82) and fixed a broken trace I saw (a leaky 
capacitor had corroded the trace between the negative side of C85 and D15, so I 
soldered a jumper wire on the back of the board) but the display still doesn't 
work. If anyone has any suggestions for getting it going, I'd greatly 
appreciate it.

Thanks,
Nathan

Re: [M100] TPDD Specifics

[Fugu ME100]

Quite a lot of other TPDD emulation software running on just about everything 
you could imagine :)  Lots and lots of M100 owners past and present have picked 
it apart so there should be something on the web to help with your work.   A 
quick web search threw up a few links, a not very exhaustive list is below to 
start with…..

Looking through Rons code on Github https://github.com/rlauzon/arduino-tpdd  
might help understand the protocol.  He also gives a good overview of the 
issues he faced on the Arduino.  This is written for an Arduino so might be 
more accessible to learn about TPDD and run the software.

Then there is DlPlus another TPDD emulator that can be used as a reference 
source.   http://www.bitchin100.com/

Also LaddieAlpha http://bitchin100.com/pub-git/

Another example  http://trs80stuff.net/tpdd/#  in python I think.

A disassembly listing of the code on the TPDD drives is also available 
https://github.com/BiggRanger/Tandy_PDD if you really want to get into the 
details.   Which itself has some useful links.

..and many more…….

From: M100 
mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of c646581 mailto:c646...@gmail.com>>
Sent: Tuesday, July 17, 2018 10:50:58 PM
To: m100@lists.bitchin100.com
Subject: [M100] TPDD Specifics

Hello!

I'm working on a TPDD hardware emulator using low-cost 
off-the-shelf-components. I can't find much online about the specifics of the 
serial connection between the M100 and the TPDD. The TPDD protocol page on the 
wiki mentions 19200/9600 baud, but nothing about flow control or how it 
negotiates the speed.

Based on trial-and-error, I did figure out that hardware flow control is needed 
before TS-DOS will try sending any data. This gives me something to work off 
of, but more details would be great.

Thanks,
Jimmy

Re: [M100] Got a DVI and rant about shipping

[Fugu ME100]

Sounds familiar I bought an M600 off eBay a few months ago.  The outer box
was really sturdy however the seller had just placed the unit on top of
two pieces of foam packing - it was free to move around the box.  The M600
is really heavy with the internal NiCd battery pack.  FedEx appear to have
them bounced it around all over the place,  it arrived as a 3D jigsaw in
about 70 pieces or so, mixed with chips and battery.  The seller offered
me a discount if I bought something else from their eBay store.

Ironically the LCD screen appears to be in near perfect condition it was
not damaged at all.

On 14/7/18, 1:46 PM, "M100 on behalf of Greg Swallow"
 wrote:

> will have to joy you Jeff. I had purchased a VM-2 to complete my
>DVI setup (M100 + DVI (2x3.5inFDD) and it was DOA. VM-2 in a cardboard
>box and the packing material, a bit of tiny bubble wrap with most bubbles
>popped, did not even wrap around the monitor one time, just kind of
>thrown in with it. Cracks all over in near every corner, tube neck was
>snapped. Sent pictures to the eBay Seller with my complaint. "You can
>keep it," he said, "It's insured." Got my money back on it fine, but had
>to wait a couple of years for another VM-2 to hit eBay. Just got it last
>month. Guess I'll have to strip the first VM-2 for spares.
>
>God Bless,
>
>GregS <><
> 

[M100] Unusual OPTROM in T102

[Fugu ME100]

Just acquired an eBay T102 with an OPTROM that was not listed in the sale
description - surprised to see it there when I was replacing the battery.
When called it sets up as TFDC99 in the menu.  Trying to run that
generates a FF error at 10.   It is housed in an EME wrap around PCB and
looks like it uses a regular EPROM.  It could be a commercial piece of
software or someones project, there are no labels on the module - does not
appear it ever had any.

A quick search of the Archive and Google did not throw anything up, just
wondering if anyone might be able to shed any light on what it
was/is/could be?

When I get time I can dump the ROM see if it has any useful copyright
text. 

Thanks!!

Re: [M100] odd REX error - anybody run into this?

[Fugu ME100]

Might also check that none of the solder joints have gone bad.  The board
might start out fine but as the solder oxidizes over time a badly soldered
joint could fail.  

Re-programming may resolve the problem but if there is a bad joint it will
just happen again or you may not be able to reprogram the device.

Worth a close inspection to make sure especially with hand assembled part.

Could also try this REX in another machine see if it behaves the same way.
 



On 29/6/18, 8:20 AM, "M100 on behalf of Jim Anderson"
 wrote:

>> -Original Message-
>> 
>> So, on powerup, the 100 loads directly to REXMGR w/o it being invoked?
>
>Exactly.
>
>> When you get back to main, does CALL 63012 do anything?
>
>It installs REXMGR on the menu, as you'd expect.  Launching REXMGR gets
>you stuck back at the same screen again, though.
>
>> Did you make sure to remove the flux after soldering? The flash chip
>> is especially sensitive to excess flux residue (in my experience).
>
>I don't think I did.  I used a flux pen and a barely-visible amount of
>flux when I built it so I don't know if there's really anything there to
>remove.  I'd have to check.
>
>This issue can most likely be resolved by re-loading the REX software,
>but I'm just hoping for an alternative fix that might keep the data
>intact - my son is very concerned about losing his stuff (although he was
>only gone to his mom's house for two days with it so I can't imagine he's
>lost much - there was a program he was working on to play a new song he's
>been composing).
>
>
>
>
>
>
>
>   jim

Re: [M100] nn - getting back involved.

[Fugu ME100]

There are at least two M100 RAM Boards on OSH Park (a DIP version and an
SM Version):

https://oshpark.com/shared_projects/V0tpeuMg

https://oshpark.com/shared_projects/Ra3VwoJo

If this is what you are looking for?  This design is based on the NEC
module from the 1980/90s.

Francesco Messineo (on this list) also builds and sells M100 memory
modules if you prefer assembled modules. :)


If you want an assembled REX module they are also available for the M100 -
as is the REX board on OSH.

Quite a few options for tweaking the Œold¹ M100.


On 27/6/18, 8:35 AM, "M100 on behalf of Nickolas Nolan"

wrote:

>I am also hoping to find or make OSH park print for model100 static ram
>to compliment 
>https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Foshpark.
>com%2Fshared_projects%2Fm3Ugar47=02%7C01%7C%7C08b27cfb38224fefc5ea08d
>5dc43932b%7C84df9e7fe9f640afb435%7C1%7C0%7C636657105138269185&
>sdata=HMpyMbHogE3lKznp2dhynDwHSkuWGw7fczlyeZWwmZ0%3D=0
>

Re: [M100] Model 102 Black Nothing After Y2K ROM install

[Fugu ME100]

Not in AZ 


The Elenco are fine I was thinking of getting one to put in my tool box.



From: M100  on behalf of Greg Swallow 

Sent: Tuesday, June 5, 2018 05:35
To: m...@bitchin100.com
Subject: Re: [M100] Model 102 Black Nothing After Y2K ROM install

Will take some time to get a probe. Micronta probes on eBay (collectible) are 
out of my reach just now. I have gift cards for Lowes, Home Depot, and Harbor 
Freight, but the probes they have are not so "logical." I can get a Elenco 
Electronics LP-560 off Amazon for less than @20 shipped. It isn't fancy, but 
should do the job. Of course if you happen to be anywhere in the Phoenix, AZ 
area, I could bring a lot of coffee and BoSa Donuts

Re: [M100] Model 102 Black Nothing After Y2K ROM install

[Fugu ME100]

You might want to invest in a Logic Probe, old school debugging :)  That
would give a good indication as to whether or not the lines are working
correctly also much easier to use than a MM.  They are quite cheap these
days, I use a Micronta Logic probe from log ago.


On 4/6/18, 8:48 PM, "M100 on behalf of Greg Swallow"
 wrote:

>Cold Boot (CTRL-Break-Reset) has been done multiple times. As well as
>complete power down, including Mem Power and removing batteries. Tracing
>I can do and difficult or not. I am working with this thing open and in
>parts. I was testing in case, but the markings are then facing the back
>of the M102. To see VDD, VEE, and VB marking and test properly I pulled
>the motherboard out with no display or keyboard attached. I'll try to
>make room to get in all on a mat, but I am short on space. Whatever needs
>to be done, I'll try and do appreciate your help.
>
>Thanks,
>
>GregS <><
>
>- Original Message -
>From: "Fugu ME100" 
>To: m...@bitchin100.com
>Sent: Monday, June 4, 2018 8:35:36 PM
>Subject: Re: [M100] Model 102 Black Nothing After Y2K ROM install
>
>OK they look good.  The VB = +3.6V (approx) when powered down,  it is the
>backup voltage for the RAM.
>
>
>It would appear that all the voltages are correct.The next step would
>be to start tracing out the address, data and control lines to make sure
>the buffers etc are all working when the unit is powered on.  Hope to
>find a buffer that does not work or other failed chip or even a failed
>joint.  It can be done with a MM but not easy.
>
>
>A cold boot might be worth trying if you have not already done so.
>

Re: [M100] Model 102 Black Nothing After Y2K ROM install

[Fugu ME100]

OK they look good.  The VB = +3.6V (approx) when powered down,  it is the 
backup voltage for the RAM.


It would appear that all the voltages are correct.The next step would be to 
start tracing out the address, data and control lines to make sure the buffers 
etc are all working when the unit is powered on.  Hope to find a buffer that 
does not work or other failed chip or even a failed joint.  It can be done with 
a MM but not easy.


A cold boot might be worth trying if you have not already done so.



From: M100  on behalf of Greg Swallow 

Sent: Tuesday, June 5, 2018 04:07
To: m...@bitchin100.com
Subject: Re: [M100] Model 102 Black Nothing After Y2K ROM install

I got VDD +5VDC, VEE -5VDC, and VB of +5VDC. No 3.6VDC on VB.

- Original Message -
From: "Fugu ME100" 
To: m...@bitchin100.com
Sent: Monday, June 4, 2018 7:06:33 PM
Subject: Re: [M100] Model 102 Black Nothing After Y2K ROM install

It does sound like there might of been some static damage on the board.  The 
ROM shares lines with the RAM wonder if a RAM has fried?  Or a buffer?


On the M100 the Vdd, Vee, Vb and GND lines are marked so it is quite easy to 
check the +5, -5V & +3.6V are on the board OK.

Re: [M100] Model 102 Black Nothing After Y2K ROM install

[Fugu ME100]

It does sound like there might of been some static damage on the board.  The 
ROM shares lines with the RAM wonder if a RAM has fried?  Or a buffer?


On the M100 the Vdd, Vee, Vb and GND lines are marked so it is quite easy to 
check the +5, -5V & +3.6V are on the board OK.


From: M100  on behalf of Greg Swallow 

Sent: Tuesday, June 5, 2018 02:59
To: m...@bitchin100.com
Subject: Re: [M100] Model 102 Black Nothing After Y2K ROM install

For sure Josh. Checked continuity after installing the two SIP rows. Have also 
checked since from top of chip leg through motherboard and sounds good. Will 
have to check the M100 Service Manual for some reference VDC check points. I 
had this happen with my first M102 mod and re-flowing the solder took care of 
it, but not doing it this time. Am afraid I fried something. Don't see any 
evidence, but I did get a solder cross between pins on a neighboring IC. Caught 
it and cleaned it before I re-assembled the M102. Have a new magnifying light 
now to help. What I had was small and not enough for my failing eyes -- I see a 
ring of five of everything. Trying to get it done before eyes get much worse. I 
also have five M100 to do with Mike Stein's PCB and three or four of those will 
hit eBay.

God Bless,

GregS <><

- Original Message -

If all you have is a MM, I'd say the next step is to verify continuity
to the ROM chip. Measure for continuity from the metal of the ROM chip
leg over to the corresponding leg on a RAM chip or the CPU. Make sure
your socket is working correctly.

-Josh

Re: [M100] Model 102 Black Nothing After Y2K ROM install

[Fugu ME100]

The 102 Ref manual is on this page http://www.club100.org/library/libdoc.html 
of the club 100 site.  This should help 


Does it work with the original ROM in the socket?




From: M100  on behalf of Greg Swallow 

Sent: Monday, June 4, 2018 22:50
To: m...@bitchin100.com
Subject: [M100] Model 102 Black Nothing After Y2K ROM install

After fixing the M102 keyboard and replacing the top-case went so well, I 
figured I'd go ahead and put in a Y2K ROM. Removed the old and put in machined 
headers to have a makeshift socket. M102 powers up, contrast can go light/dark 
on the screen, but nothing else. Checked the solder joints and related traces 
on the PCB with and without the ROM. Unit has good batteries and 6VDC. I've 
done this before -- twice, so this one has me in a quandary. I am limited to my 
Fluke 77/BN for testing. Have not been able to find the M102 Service Manual 
anywhere to have more reference. Did notice the LCD ribbon was a bit pushed in 
(one wire worth) on the keyboard side of the ribbon.

With that I pose the question of, any ideas?

Appreciate anything,

GregS <><

Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 100

[Fugu ME100]

That’s great.   Pleased to hear you tracked it down - another 100 survives  :)  
Now you have two and that’s how it all starts….

If you want to build RAM modules for the M100 I have two RAM PCBs on OSH Park: 
SMD Version and DIP version.   The design is based on the old NEC modules.
https://oshpark.com/shared_projects/V0tpeuMg
https://oshpark.com/shared_projects/Ra3VwoJo

There are a few different options to add pins to the PCBs for mounting.

From: M100 
> 
on behalf of Jeffrey Birt >
Reply-To: >
Date: Sunday, May 13, 2018 at 6:52 PM
To: >
Subject: Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 
100

Update…

It was the RAM module. After thinking about it after Fugu’s email the other day 
it occurred to me I had done a capture of the standard RAM bank select lines 
(and I happened to dave it) and after looking at it again it looked fine. This 
evening I pulled the standard RAM module out, split apart a 30 pin DIP socket 
to make two 15 pin SIPs and plugged in of the option RAMs. AND…nothing. Sigh…

Then I noticed I had not plugged the ROM back in after cleaning the flux from 
the board. So, the ROM was installed, and STRL-BRK done on power up and…It’s 
ALIVE! Bwa-ha-ha-ha! It’s ALIVE!

I tried reflowing the original standard RAM module and it still did not work. I 
could ohm out each line to each individual RAM chip and maybe get lucky and 
find one open trace, but I would guess that a bad RAM chip is more likely. I’ll 
look into making some more RAM module or buying a few, for now I have 16K.

As luck would have it the second M100 I bought from across the state arrived 
yesterday, I still have not opened it yet. It is supposed to work, got it from 
the original owner who seemed like a nice guy. A grand total of $61 including 
shipping. Now I’ll put together an order for enough caps to finish recapping 
the first M100 and re-cap the 2nd one while I’m at it. I also need to try and 
calculate a super-cap size that will at least match the original NiCad battery.

Thanks again everyone (especially Fugu) for your help.

Jeff

Re: [M100] Rex startup time

[Fugu ME100]

After CALL 63012 the return to the menu with REXMGR loaded should take ~1s it 
is almost instant.   You may also want to try a cold boot just in case 
something is in the RAM.

If it is hanging (and the board is installed correctly) then there is most 
likely a dry/bad joint on the Flash memory or Xliinx part.  The module can 
appear to program OK even with dry/bad joints.   When programming with V4.9, as 
it clears the Flash memory the block count should take about 1s/block to clear. 
 If it is faster than that the module will fail, similarly when copying the REX 
software to block 0 it should not be instant.

Probably best to inspect the soldering to make sure there are no bridges or bad 
joints.  A magnifying glass and dental pick are good tools for the inspection 
process.  Double check the part orientation too.If the module is based on 
the OSH board then check there is no copper flashing across the board edge 
pins, the routing process during manufacture can cause pin shorts along the 
side.   OSH are not really set up to build castellated boards it does work but 
needs extensive cleanup especially if they put the mouse bites on the 
castellated edge :(

From: M100 
> 
on behalf of "J.T." >
Reply-To: >
Date: Monday, May 14, 2018 at 6:12 AM
To: "m100@lists.bitchin100.com" 
>
Subject: [M100] Rex startup time


Just got done constructing and installing a REX using build 162. The flash of 
the Xilinx and the loading of the Rex software via Tpdd went smooth. It all 
looks right up until I actually try to do the call 63012.  The Rex is installed 
in a 32k model 100 and the previous option rom worked flawlessly, so I know the 
socket works properly.  So how long does the REX take to start? Am I just being 
impatient ?

Sent from Yahoo Mail for 
iPhone

Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 100

[Fugu ME100]

The address could be stuck internally on the RAM so the address line would 
appear OK externally.  The fact the ROM runs correctly with the shared Address 
line would indicate the address lines are generally OK.  It could be floating 
on the module as you suggest,  look to see if there is any corrosion on the 
module and the pins to the module are in good condition.  Perhaps try reflowing 
each of the module pins to make sure there are no dry joints?

I am currently looking into producing some sort of test harness for the model T 
however the lack of socket for the 8085 makes it hard to add in a test fixture. 
 Even trying to tri-state the 8085 appears difficult as it does not tri-state 
the ALE, all the other lines are OK.  Another option would be to try and 
monitor what it does with something that plugs into the RAM socket.  That way 
at least there would be a trace showing the bus activity.   Being able to 
single step the 8085 might be another option with a known ROM in the socket.

From: M100 
> 
on behalf of Jeffrey Birt >
Reply-To: >
Date: Thursday, May 10, 2018 at 7:13 AM
To: >
Subject: Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 
100

Very good observation. I believe that I did check that all address lines were 
toggling at the RAM module, but I will check again. Perhaps A4 is floating? 
Yes, a RAM test would be nice. I think a diagnostic ROM could be made to do 
that, just start out by testing the standard RAM (without any stack operations) 
There is a diagnostic cartridge for the C64 that does that, of course if the 
address decoding is not working then the results of such a test are bogus 

Thanks,
Jeff

Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 100

[Fugu ME100]

If A4 is stuck at 0 (or 1) then the SP and copy location would overlap, eg 
F5F0H would become F5E0H and overwrite the stack area - at least 6 bytes of it. 
 The RAM modules are made up of 4 ICs so it it possible that only the top most 
RAM has a fault the others could be fine. If the RAM operation occurs in the 
other 3 RAM ICs then there would not be a problem.  The other CALL 7EE1H works 
because there are no other RAM ops that could damage the stack.

As the Address lines are shared with the ROM and it seems to work fine it 
really only leaves the RAM module or decoder IC.   I am tending towards the RAM 
module.  Would be nice to somehow run a RAM test :)


F5F0H,  0101 111? B   start of RAM copy destination
F690H,  0110 1001 B   end of RAM copy destination
F5E6H,  0101 111? 0110B   start of stack, grows down.

Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 100

[Fugu ME100]

Does it only execute the loop once and get stuck for the first time at 2574H?

The 49H in the data dump is most likely the C9H for the RET.  The next two byte 
are the return address from the stack.  They could be 0A57H, 0AD7H, 8A57, 8AD7H 
or  other permutations.  As this routine is writing to the RAM it is quite 
possible it is trashing the stack and destroying the return address - could be 
a bad RAM chip or decoder.

There are at least two different versions of the M100 motherboard one has 
700mil RAM modules and the other 750mil.  Not sure if there are any ROM 
differences or other hardware differences.

Re: [M100] Tandy Model 102 Portable keyboard issue.

[Fugu ME100]

There is a diode associated with the key it could of failed.  I think the 
diodes are on the top of the board so you may have to trace out carefully to 
find the diode for the C-Key.



I notice the solder points underneath don't line up exactly to the top.

Re: [M100] Files XFER

[Fugu ME100]

One option is to run Mcomm on the PC to act as a TPDD Server and use the
null modem cable to connect the PC and M100.
http://www.club100.org/memfiles/index.php?===Kurt
%20McCullum

Mcomm can inject RAM TS-DOS or with the REX you can use that OPT ROM
version.  This should allow you to read and write files to the M100 from
the PC.  The club100 site http://www.club100.org/ has quite a lot of
programs (See: The BBS Libraries dating back to 1983) to explore either
BASIC or ML, these can all be copied to the Mcomm folder for loading onto
the M100.  There is also a section on
http://www.club100.org/library/howto00.html how to use the BA - DO trick.

In addition there is an Mcomm version that can run on Android if you
prefer to use that solution.


On 7/5/18, 10:52 PM, "M100 on behalf of David Laffineuse"

wrote:

>So I am sure that this question has been asked 1000 times but I still
>cannot find a simple and satisfactory answer in the archives.  It is
>about file transfer.  Now I can do text file transfers between a 64-bit
>PC and the M100 via HyperTerminal and a null modem cable.  That works
>well.   But now, how do I get programs/applications onto the M100?  Where
>do I find those programs, how do I setup the PC and M100 to transfer them
>for the PC to the M100, how does all that work?  If that helps I just
>received REX.  Thanks in advance for your help!
>
>
>Sent from my iPhone

Re: [M100] Replaced NiCD with NiMH

[Fugu ME100]

The motherboard hooks under the clips on the 102  If  left on top the case 
will not close properly.


The 100 and 102 are a breeze to work on compared to the 200.   Just getting the 
screen cable detached is almost impossible, reattaching is a nightmare.  There 
may be a trick but it was beyond me.  The bolt lengths for the 200 hinge are 
slightly different if you get it wrong then the plastic cracks.

Re: [M100] 8K RAM module

[Fugu ME100]

If you have access to DigiKey then you can always buy parts there (or Mouser).  
 I used a 74HC148 as the decoder chip when I built my M100 RAM module.  There 
are quite a lot of ways to decode the 4 Chip Enables on the RAM socket using a 
single IC.

These are DIP parts.

AS6C6264-55PCN RAM  = 1450-1036-ND  - $2.43
74HC148Priority Decoder =  296-8233-5-ND - 43c

If you want to try the 74HC86 =  296-8375-5-ND - 40c

Cost ~$3, however S would be extra.


From: M100 
<m100-boun...@lists.bitchin100.com<mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of Diggy Dude 
<therealdiggyd...@gmail.com<mailto:therealdiggyd...@gmail.com>>
Reply-To: <m...@bitchin100.com<mailto:m...@bitchin100.com>>
Date: Monday, May 7, 2018 at 9:26 AM
To: <m...@bitchin100.com<mailto:m...@bitchin100.com>>
Subject: Re: [M100] 8K RAM module

Well, it looks like the only 7486s I have on hand are LS. What with buying bulk 
parts I'll probably never use and waiting for the slow boat from China, it'll 
probably be more cost-effective just to buy the module on Arcade Shopper. 
Thanks for your help, guys!

-- Jim

On Mon, May 7, 2018 at 11:04 AM, Francesco Messineo 
<francesco.messi...@gmail.com<mailto:francesco.messi...@gmail.com>> wrote:
On Mon, May 7, 2018 at 4:42 PM, Diggy Dude 
<therealdiggyd...@gmail.com<mailto:therealdiggyd...@gmail.com>> wrote:
> To make sure I understand:
>
> Clean all pads and leads with flux.Will a flux pen suffice, or should liquid
> flux be used?

no, flux residue after soldering has to be removed. I use water-based
flux, so I clean the boards with water and bake them to remove the
water

>
> What specific 74HC and SRAM devices do you use?

I use AS6C6264SCN memories, though they aren't guaranteed to have
standby current  lower than 4 uA, but I measure every module to be
sure it meets this requirement. It's the only part that can be found
new at this time. I have used  batoches of several other SRAMs when
I've found a good deal on ebay for example.
I do all glue logic with a single 74HC86.

>
> On Mon, May 7, 2018 at 2:45 AM, Francesco Messineo
> <francesco.messi...@gmail.com<mailto:francesco.messi...@gmail.com>> wrote:
>>
>> On Mon, May 7, 2018 at 9:08 AM, Diggy Dude 
>> <therealdiggyd...@gmail.com<mailto:therealdiggyd...@gmail.com>>
>> wrote:
>> > Thanks, Fugu!
>> >
>> > So the modern solution is a single SRAM and capacitor on a SOIC-to-DIP
>> > breakout? What's the RAM chip they're using?
>>
>> and a logic chip (there're a few different approaches here) to combine
>> the separate chip selects to a couple of addresses and a single select
>> signal. My own version of the circuit uses the fewest ports possible
>> (at least if nobody comes up with a different approach I couldn't
>> think of).
>> The RAM chip must be a CMOS static ram, 8kx8 and with low power
>> standby (not all have this feature). The original 8k modules were
>> specified for 4 uA max standby current, that allows the standby
>> battery to keep the RAM content for over a month. Usually the suitable
>> chips have L or LL in the part number, but you better check the
>> datasheet for the fine details. Most of the suitable RAM chips have a
>> measured standby current of 0.1 uA (often less) at 3.3V if the chip
>> select are driven with the correct voltages. At these current levels,
>> cleaning the soldering flux is a must. I've measured up to 15 uA of
>> standby current on badly cleaned modules. YMMV.
>> Glue logic *must* be 74HC family, it has a suitable current draw at
>> 3.3V standby and suitable speed. In one case I've used 74AHC and it
>> worked well too.
>>
>> >
>> > -- Jim
>> >
>> > On Sun, May 6, 2018 at 10:29 PM, Fugu ME100 
>> > <b4me...@hotmail.com<mailto:b4me...@hotmail.com>> wrote:
>> >>
>> >> You could try
>> >>
>> >> https://www.arcadeshopper.com/wp/?page_id=11#!/8k-RAM-module-for-Model-100/p/104430801/category=28313042<https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.arcadeshopper.com%2Fwp%2F%3Fpage_id%3D11%23!%2F8k-RAM-module-for-Model-100%2Fp%2F104430801%2Fcategory%3D28313042=02%7C01%7C%7Cb8bb797123af403b53b708d5b43745b3%7C84df9e7fe9f640afb435%7C1%7C0%7C636613071840276763=F4%2FPkPnXMzef8DB1N50baPzETrsjrbFiag0daGnMhzI%3D=0>
>> >>
>> >> They have the M100 modules if you want to buy.
>> >>
>> >> If you want to build your own there are PCBs on OSH Park for surface
>> >> mount
>> >> and DIP versions.
>> >>
>> >> No need for any pillaging :)
>> >>
>> >> From: M100 
>>

Re: [M100] 8K RAM module

[Fugu ME100]

You could try 
https://www.arcadeshopper.com/wp/?page_id=11#!/8k-RAM-module-for-Model-100/p/104430801/category=28313042

They have the M100 modules if you want to buy.

If you want to build your own there are PCBs on OSH Park for surface mount and 
DIP versions.

No need for any pillaging :)

From: M100 
> 
on behalf of Diggy Dude 
>
Reply-To: >
Date: Sunday, May 6, 2018 at 8:13 PM
To: >
Subject: [M100] 8K RAM module

Anyone know where I can get an additional 8K for my 24K M100 without pillaging 
another M100? Let's face it: if I got another M100, I'd be inclined to leave it 
intact.

Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 100

[Fugu ME100]

Yes quite possible a bad 81C55, M15 or keyboard would cause an issue.  Try 
putting in one of the RAM modules see if that helps.  Unfortunately the 81C55 
also controls the LCD.



I should try and see if it is actually reading the ctrl-brk, what if there is a 
problem with the keyboard or key decoding?  Looking at the source it looks like 
it will trigger a cold boot when it senses a change in memory size or a new 
option ROM being installed to.

Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 100

[Fugu ME100]

Yes that is sequence.


It does retain it but there is the potential for random data to be in the RAM 
on each power cycle without the ctrl-break.  With the NiCd on board the memory 
would be in the same state as setup during the clean boot.


So far everything you have done looks good.



From: M100 <m100-boun...@lists.bitchin100.com> on behalf of Jeffrey Birt 
<bir...@soigeneris.com>
Sent: Monday, May 7, 2018 03:12
To: m...@bitchin100.com
Subject: Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 
100


The NiCad only powers the RAM when there is no other power source available. 
When you have AA’s installed or a power adapter plugged in then that is what is 
powering the memory, even when the power switch is off. My first tests were 
done with the NiCad removed but AA’s installed so the RAM was always powered. 
It was rather inconvenient though thus I installed the temporary battery and 
lifted one leg of the diode so it would not be trying to charge the lithium 
battery.



I did try a CTRL-BRK + reset several times with no apparent difference in 
results. Just to make sure I’m not misunderstanding this key sequence it is the 
CTRL key in the low left, BRK on top row of function keys and the reset button 
on the back?



Thanks again,

Jeff



From: M100 <m100-boun...@lists.bitchin100.com> On Behalf Of Fugu ME100
Sent: Sunday, May 6, 2018 8:40 PM
To: m...@bitchin100.com
Subject: Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 
100



Agreed the lack of NiCd might be having more impact than expected on a machine 
that expects data to be retained in RAM during power off.



From: M100 
<m100-boun...@lists.bitchin100.com<mailto:m100-boun...@lists.bitchin100.com>> 
on behalf of "John R. Hogerhuis" <jho...@pobox.com<mailto:jho...@pobox.com>>
Reply-To: <m...@bitchin100.com<mailto:m...@bitchin100.com>>
Date: Sunday, May 6, 2018 at 5:49 PM
To: <m...@bitchin100.com<mailto:m...@bitchin100.com>>
Subject: Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 
100



Now that you're applying a voltage in place of the removed NiCd have you 
attempted a cold start?



-- John.

Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 100

[Fugu ME100]

Agreed the lack of NiCd might be having more impact than expected on a machine 
that expects data to be retained in RAM during power off.

From: M100 
> 
on behalf of "John R. Hogerhuis" >
Reply-To: >
Date: Sunday, May 6, 2018 at 5:49 PM
To: >
Subject: Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 
100

Now that you're applying a voltage in place of the removed NiCd have you 
attempted a cold start?

-- John.

Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive Model 100

[Fugu ME100]

It is the rising edge of RD that is used to latch the data into the 8085.  The 
ROM has from the falling edge to rising edge to deliver the data.  The decoder 
is level sensitive not edge, so the rising edge will not only disable the ROM 
but also latch in the ROM data.  That looks like it is working as expected.

The fact the CE is sort of random probably means there is random data in the 
RAM,  it could be heading off to another RAM bank because of this after the IO 
operations.   I just wonder if the missing NiCD is causing some problems.  The 
Model T family is somewhat unique for its day in that it expects the RAM to 
retain the data between power cycles.