Re: [M100] DVI cable for 102

[Chris Kmiec]

Brian, that DVI Wiki is awesome, thank you. I've ordered some
gender-changer male pin headers, so next weekend I should have a working
102 setup.

On a side note, LCD on the 100 that came with the DVI has started
flickering and dimming, but the computer itself has also started crashing,
after using for a bit. I think I'll go through all the caps and replace
them, and clean the LCD connectors.

On Fri, Mar 16, 2018 at 10:58 AM, Mike Stein  wrote:

> That's a possibility, but as far as I can tell no combination of what
> Chris has would work with a 102/200.
>
> m
>
> - Original Message -
> *From:* Brian White 
> *To:* m...@bitchin100.com
> *Sent:* Friday, March 16, 2018 9:49 AM
> *Subject:* Re: [M100] DVI cable for 102
>
> Probably someone ends up with 3 cables because probably a single long,
> 100-only cable (and a 100-only system disk) came with the DVI, and the two
> short ones came later with the 100/200 system disk.
>
>
>
>

Re: [M100] Power Adapter Questions

[kurt . mccullum]

Thanks everyone. Think I'll take Mike's advice and just mark them. I was toying with the idea of using only one but there really isn't a good reason to do so.
Kurt
On Mar 16, 2018 4:52 PM, Brian White  wrote:Ubdervolting draws more current, which may be stressing some part even if it still works.Both under and over voltage are bad for different reasons. The only spec that you can exceed harmlessly is a ps that can deliver more current (not voltage) than needed is harmless.A ps that can't deliver enough current won't hurt the device, except by potentially scrambling data from instability and crashes, but it will kill the ps.On Fri, Mar 16, 2018, 1:04 PM John Gardner  wrote:IME 6 VDC (8201a) works fine.

 ...


On 3/16/18, Mike Stein  wrote:
> I think it would depend on the adapter type; I would measure the *actual*
> voltage of both adapters, both unplugged and plugged in with the computer
> turned on.
>
> They do have regulators, in fact they have complete regulated switching
> power supplies. I really wouldn't recommend using the 8.5V supply instead of
> the 6V; extra voltage is usually dissipated in heat, which could possibly
> cause a problem with extended use.
>
> How about just colour-coding the connectors and jacks?
>
> m
>   - Original Message -
>   From: Kurt McCullum
>   To: Model 100 Discussion
>   Sent: Friday, March 16, 2018 11:52 AM
>   Subject: [M100] Power Adapter Questions
>
>
>    A quick power question for those who may be able to answer this question.
> On my NEC 8201 the AC power adapter is rated for 8.5 volts. The AC power
> adapter for my 100/102/200/TPDD2 is 6v. I have both on my desk but get them
> mixed up at times even though I try not to. The units seem happy with either
> voltage. So I'm wondering if there is a risk of damage when I accidentally
> put the 8.5v plug in my 200 or 102. Do they have an internal regulator that
> prevents damage?
>
>
>   And one other question. I am getting ready to make the modification to my
> 200 which allows it to have rechargeable batteries rather than regular AA
> cells. This is an option which the service manual refers to. It involves
> soldering two small jumpers. Will I need to run a higher voltage to charge
> these batteries or is 6v enough?
>
>
>   Kurt

Re: [M100] Power Adapter Questions

[Brian White]

Ubdervolting draws more current, which may be stressing some part even if
it still works.

Both under and over voltage are bad for different reasons.

The only spec that you can exceed harmlessly is a ps that can deliver more
current (not voltage) than needed is harmless.

A ps that can't deliver enough current won't hurt the device, except by
potentially scrambling data from instability and crashes, but it will kill
the ps.

On Fri, Mar 16, 2018, 1:04 PM John Gardner  wrote:

> IME 6 VDC (8201a) works fine.
>
>  ...
>
>
> On 3/16/18, Mike Stein  wrote:
> > I think it would depend on the adapter type; I would measure the *actual*
> > voltage of both adapters, both unplugged and plugged in with the computer
> > turned on.
> >
> > They do have regulators, in fact they have complete regulated switching
> > power supplies. I really wouldn't recommend using the 8.5V supply
> instead of
> > the 6V; extra voltage is usually dissipated in heat, which could possibly
> > cause a problem with extended use.
> >
> > How about just colour-coding the connectors and jacks?
> >
> > m
> >   - Original Message -
> >   From: Kurt McCullum
> >   To: Model 100 Discussion
> >   Sent: Friday, March 16, 2018 11:52 AM
> >   Subject: [M100] Power Adapter Questions
> >
> >
> >A quick power question for those who may be able to answer this
> question.
> > On my NEC 8201 the AC power adapter is rated for 8.5 volts. The AC power
> > adapter for my 100/102/200/TPDD2 is 6v. I have both on my desk but get
> them
> > mixed up at times even though I try not to. The units seem happy with
> either
> > voltage. So I'm wondering if there is a risk of damage when I
> accidentally
> > put the 8.5v plug in my 200 or 102. Do they have an internal regulator
> that
> > prevents damage?
> >
> >
> >   And one other question. I am getting ready to make the modification to
> my
> > 200 which allows it to have rechargeable batteries rather than regular AA
> > cells. This is an option which the service manual refers to. It involves
> > soldering two small jumpers. Will I need to run a higher voltage to
> charge
> > these batteries or is 6v enough?
> >
> >
> >   Kurt
>

Re: [M100] Power Adapter Questions

[John Gardner]

IME 6 VDC (8201a) works fine.

 ...


On 3/16/18, Mike Stein  wrote:
> I think it would depend on the adapter type; I would measure the *actual*
> voltage of both adapters, both unplugged and plugged in with the computer
> turned on.
>
> They do have regulators, in fact they have complete regulated switching
> power supplies. I really wouldn't recommend using the 8.5V supply instead of
> the 6V; extra voltage is usually dissipated in heat, which could possibly
> cause a problem with extended use.
>
> How about just colour-coding the connectors and jacks?
>
> m
>   - Original Message -
>   From: Kurt McCullum
>   To: Model 100 Discussion
>   Sent: Friday, March 16, 2018 11:52 AM
>   Subject: [M100] Power Adapter Questions
>
>
>A quick power question for those who may be able to answer this question.
> On my NEC 8201 the AC power adapter is rated for 8.5 volts. The AC power
> adapter for my 100/102/200/TPDD2 is 6v. I have both on my desk but get them
> mixed up at times even though I try not to. The units seem happy with either
> voltage. So I'm wondering if there is a risk of damage when I accidentally
> put the 8.5v plug in my 200 or 102. Do they have an internal regulator that
> prevents damage?
>
>
>   And one other question. I am getting ready to make the modification to my
> 200 which allows it to have rechargeable batteries rather than regular AA
> cells. This is an option which the service manual refers to. It involves
> soldering two small jumpers. Will I need to run a higher voltage to charge
> these batteries or is 6v enough?
>
>
>   Kurt

Re: [M100] 8K RAM Chip

[Mike Stein]

Hi Frank,

Any chance you'd share the PCB files for your RAM modules so we can build some?

m

Re: [M100] Power Adapter Questions

[Mike Stein]

I think it would depend on the adapter type; I would measure the *actual* 
voltage of both adapters, both unplugged and plugged in with the computer 
turned on.

They do have regulators, in fact they have complete regulated switching power 
supplies. I really wouldn't recommend using the 8.5V supply instead of the 6V; 
extra voltage is usually dissipated in heat, which could possibly cause a 
problem with extended use.

How about just colour-coding the connectors and jacks?

m
  - Original Message - 
  From: Kurt McCullum 
  To: Model 100 Discussion 
  Sent: Friday, March 16, 2018 11:52 AM
  Subject: [M100] Power Adapter Questions


   A quick power question for those who may be able to answer this question. On 
my NEC 8201 the AC power adapter is rated for 8.5 volts. The AC power adapter 
for my 100/102/200/TPDD2 is 6v. I have both on my desk but get them mixed up at 
times even though I try not to. The units seem happy with either voltage. So 
I'm wondering if there is a risk of damage when I accidentally put the 8.5v 
plug in my 200 or 102. Do they have an internal regulator that prevents damage?


  And one other question. I am getting ready to make the modification to my 200 
which allows it to have rechargeable batteries rather than regular AA cells. 
This is an option which the service manual refers to. It involves soldering two 
small jumpers. Will I need to run a higher voltage to charge these batteries or 
is 6v enough?


  Kurt

Re: [M100] 8K RAM Chip

[Mike Stein]

- Original Message - 
From: "Francesco Messineo" 
To: 
Sent: Friday, March 16, 2018 11:56 AM
Subject: Re: [M100] 8K RAM Chip


>>> I think it can be done, but you anyway need logic to reconstruct the 
>>> addresses, so why bother with diodes?

>> ...they're used in this case to form three AND gates.
> 
> yes, I know the history :)


My point was that you don't need 'logic'; the diodes are used instead of an IC.
---

> I was only wondering if they checked the standby current draw, that's all.


Good question.

m

Re: [M100] Power Adapter Questions

[Lee Kelley]

I've used both and it's all good.  We just have to remember that the
polarity is negative center, unlike most electronics, when we use strange
power supplies.

On Fri, Mar 16, 2018 at 11:32 AM, Josh Malone  wrote:

> The 102 (only tech ref I have handy - see p. 30) uses a DC-DC
> converter to regulate the 5v supply. I'm not good enough with power
> circuits to guess what the maximum safe input voltage is, but I'll bet
> 8.5 is fine.
>
> On Fri, Mar 16, 2018 at 12:19 PM, John Gardner  wrote:
> > I've used rechargeable NiMH (Eneloops) in 8201a packs
> >
> > for many years.  In practice,  I have'nt noticed a downside
> >
> > to plug-in cells,  & there is one distinct advantage - It allows
> >
> > use of a purpose-built Eneloop charger (Maha C9000).
> >
> >  ...
> >
> >
> > On 3/16/18, Kurt McCullum  wrote:
> >>  A quick power question for those who may be able to answer this
> question.
> >> On my NEC 8201 the AC power adapter is rated for 8.5 volts. The AC power
> >> adapter for my 100/102/200/TPDD2 is 6v. I have both on my desk but get
> them
> >> mixed up at times even though I try not to. The units seem happy with
> either
> >> voltage. So I'm wondering if there is a risk of damage when I
> accidentally
> >> put the 8.5v plug in my 200 or 102. Do they have an internal regulator
> that
> >> prevents damage?
> >> And one other question. I am getting ready to make the modification to
> my
> >> 200 which allows it to have rechargeable batteries rather than regular
> AA
> >> cells. This is an option which the service manual refers to.
> >> It involves soldering two small jumpers. Will I need to run a higher
> voltage
> >> to charge these batteries or is 6v enough?
> >> Kurt
>



-- 
*"I will never in my lifetime make a film that cannot be seen by the whole
family"*  Arther P. Jacobs

Re: [M100] Power Adapter Questions

[Josh Malone]

The 102 (only tech ref I have handy - see p. 30) uses a DC-DC
converter to regulate the 5v supply. I'm not good enough with power
circuits to guess what the maximum safe input voltage is, but I'll bet
8.5 is fine.

On Fri, Mar 16, 2018 at 12:19 PM, John Gardner  wrote:
> I've used rechargeable NiMH (Eneloops) in 8201a packs
>
> for many years.  In practice,  I have'nt noticed a downside
>
> to plug-in cells,  & there is one distinct advantage - It allows
>
> use of a purpose-built Eneloop charger (Maha C9000).
>
>  ...
>
>
> On 3/16/18, Kurt McCullum  wrote:
>>  A quick power question for those who may be able to answer this question.
>> On my NEC 8201 the AC power adapter is rated for 8.5 volts. The AC power
>> adapter for my 100/102/200/TPDD2 is 6v. I have both on my desk but get them
>> mixed up at times even though I try not to. The units seem happy with either
>> voltage. So I'm wondering if there is a risk of damage when I accidentally
>> put the 8.5v plug in my 200 or 102. Do they have an internal regulator that
>> prevents damage?
>> And one other question. I am getting ready to make the modification to my
>> 200 which allows it to have rechargeable batteries rather than regular AA
>> cells. This is an option which the service manual refers to.
>> It involves soldering two small jumpers. Will I need to run a higher voltage
>> to charge these batteries or is 6v enough?
>> Kurt

Re: [M100] DVI cable for 102

[Mike Stein]

Interesting; yeah, that's what I thought it had to be to explain what's 
happening. Here's what I think:

The 'long' cable is probably the standard M100>DVI cable that came with the 
DVI, and it would presumably work if you plugged it into the M100.

The short M100 cable is probably a home-made shorter version of the same cable 
that does exactly what I did with mine, namely stick the connector on the back 
of the M100 to avoid having to unplug the internal bus connector every time.

The short DVI cable is probably a 102/200 cable that's been modified in order 
to use it as an extension to connect the homemade M100 cable to the DVI.

The problem is that because (s)he used the same 'non-standard' DIP plug inside 
the M100 as the original, the connector on the back of the M100 is 'reversed' 
from the same connector on a 102/200.

For a 102 you have to swap the pairs somewhere along the way; the easiest way 
would probably be to find an old female-female 2x20 cable such as what was used 
for PATA IDE hard disks and insert a set of pins in one end as Brian shows near 
the bottom of his Wiki; of course you could also make a 'twisted' cable as he 
shows elsewhere.

m
  - Original Message - 
  From: Chris Kmiec 
  To: m...@bitchin100.com 
  Sent: Thursday, March 15, 2018 8:51 PM
  Subject: Re: [M100] DVI cable for 102


  Ok, I lied, sneaked in to take few pix before dinner night out... Enjoy, and 
let me know if you want me to take any other angle!


  https://1drv.ms/f/s!AiOtw8Sr4zlvgaBRTB4K9WCxOOmoeQ



  On Thu, Mar 15, 2018 at 7:26 PM, Chris Kmiec  wrote:

And that's what it appears to be doing - both cables connected work great 
with my m100, but the short DVI to system bus part does not respond to anything 
on my 102.




On Mar 15, 2018 5:36 PM, "Mike Stein"  wrote:

  Agreed; we need better pictures ;-)

  And yes, the insert is definitely confusing.

  But what's also confusing is that it sounds like it works with an M100 
with both cables connected together. I don't see any twists, so I wonder if 
maybe someone modified the 102/200 cable to remove the twists and turn it into 
an M100 extension; in that case both cables connected together would work in an 
M100 but the 102/200 part would not work on the 102.

  (I think; now *I* am getting confused... ;-)

  m

- Original Message - 
From: Brian White 
To: m...@bitchin100.com 
Sent: Thursday, March 15, 2018 5:45 PM
Subject: Re: [M100] DVI cable for 102


Ah, looking at that insert again, I realize it gives all the answers, 
except, looking longer, it seems to give wrong answers that don't add up.


1) The 2-part cable came with the 200-compatible system disk, and they 
both came together as their own package.


2) The drawing seems to say that these are really just two separate 
cables, not a single two-part cable, and the written directions seem to agree, 
it's just that they don't quite say it straight out simply like that. But if 
you do what they say, it ends up resolving out to that.


It's just confusing because of several things:


* The cables might have shipped connected together, according to the 
written directions.

* The drawing looks like one cable with a break with connectors that 
mate, the drawing isn't clear enough to show that "the blue connector" doesn't 
actually look the same or fit into that other cable right next to it.

* The directions actually say "the special two-part cable included".



So, I *think* this is not a two-part cable at all, just simply plain 
old, two different cables to work with two different models of computer.

One cable is for 102 & 200, the other cable is for 100, and that's it, 
the cables are never supposed to be connected to each other.


Which is why I'd really like to see some clear full close pics of the 
cables and connectors from different angles, because if this is true, then 
there should be some funky twists in the wires somewhere, or else these are 
funky connectors that don't map the wires to the pins the same way every other 
connector in the world does at least today.





On Thu, Mar 15, 2018 at 5:17 PM, Brian White  wrote:

  There is a single sheet insert that came with one of my DVI manuals 
that shows a two-part cable, where I think the deal is there's really 3 total 
parts, one for 100, one for 102 & 200, and one for the DVI.

  I scanned it and uploaded it to Archive.org a few weeks ago. It's a 
little paper about the size of a paperback book. Perhaps these came later along 
with the 100/200 version of the system disk? Maybe the mid-way connector 
performs the twists?

  https://archive.org/details/DVI263806Notice


  I too would like specifically more and clearer pictures of the 
cables, especially the connectors. Not the 

Re: [M100] DVI cable for 102

[Mike Stein]

That's a possibility, but as far as I can tell no combination of what Chris has 
would work with a 102/200.

m
  - Original Message - 
  From: Brian White 
  To: m...@bitchin100.com 
  Sent: Friday, March 16, 2018 9:49 AM
  Subject: Re: [M100] DVI cable for 102


  Probably someone ends up with 3 cables because probably a single long, 
100-only cable (and a 100-only system disk) came with the DVI, and the two 
short ones came later with the 100/200 system disk.

Re: [M100] Model 100 Backup Battery Replacement

[Mike Stein]

e.g.:
https://www.ebay.com/itm/4-pcs-60mAh-3-6V-Ni-CD-Rechargeable-Battery-Button-Cell-with-Tab-Green-/401159712873?hash=item5d66fb7069

or just go to your local dollar store and pick up a 3.6V portable phone 
battery; it'll be a little larger but last longer.

e.g.:
https://www.ebay.com/itm/Replacement-Home-Phone-Battery-Ni-MH-AAA-300mAh-with-universal-Connector-3-6V/352134685746?epid=2163009360=item51fcdce432:g:qwMAAOSww5JZhB1K

m
  - Original Message - 
  From: Paul Sussman 
  To: m100@lists.bitchin100.com 
  Sent: Friday, March 16, 2018 6:53 AM
  Subject: [M100] Model 100 Backup Battery Replacement


  Can anyone please recommend a source for the correct internal backup battery 
for the M100? I want to be sure I purchase the correct one.

   

  Thanks,

  Paul

   

  Paul

   

Re: [M100] Power Adapter Questions

[John Gardner]

I've used rechargeable NiMH (Eneloops) in 8201a packs

for many years.  In practice,  I have'nt noticed a downside

to plug-in cells,  & there is one distinct advantage - It allows

use of a purpose-built Eneloop charger (Maha C9000).

 ...


On 3/16/18, Kurt McCullum  wrote:
>  A quick power question for those who may be able to answer this question.
> On my NEC 8201 the AC power adapter is rated for 8.5 volts. The AC power
> adapter for my 100/102/200/TPDD2 is 6v. I have both on my desk but get them
> mixed up at times even though I try not to. The units seem happy with either
> voltage. So I'm wondering if there is a risk of damage when I accidentally
> put the 8.5v plug in my 200 or 102. Do they have an internal regulator that
> prevents damage?
> And one other question. I am getting ready to make the modification to my
> 200 which allows it to have rechargeable batteries rather than regular AA
> cells. This is an option which the service manual refers to.
> It involves soldering two small jumpers. Will I need to run a higher voltage
> to charge these batteries or is 6v enough?
> Kurt

Re: [M100] 8K RAM Chip

[Francesco Messineo]

On Fri, Mar 16, 2018 at 4:02 PM, Mike Stein  wrote:
> - Original Message -
> From: "Francesco Messineo" 
> To: 
> Sent: Friday, March 16, 2018 5:19 AM
> Subject: Re: [M100] 8K RAM Chip
>
>
>
>>Well, I don't know, my 700 mils modules work well, I think the difference is 
>>so relevant.
>
> (I guess you meant irrelevant?) That's what I thought, until you brought it 
> up... ;-)

well yes, that's what I meant to write. I was sure the spacing was
right 700 mils as it worked for me.

> ---
>
>>> As to using diodes, I've often used this technique...
>
>> I think it can be done, but you anyway need logic to reconstruct the 
>> addresses, so why bother with diodes?
>
> Diodes can be used as logic elements; as a matter of fact, before TTL there 
> was DTL (Diode-transistor logic):
> https://en.wikipedia.org/wiki/Diode%E2%80%93transistor_logic
>
> That's how they're used in this case to form three AND gates.

yes, I know the history :)

> ---
>>>I use only one logic chip for all the work.
>
> I'm not saying that diodes are a better way of doing it, just that it's a 
> different approach used by at least one of the commercial modules.

I was only wondering if they checked the standby current draw, that's all.

Frank

[M100] Power Adapter Questions

[Kurt McCullum]

 A quick power question for those who may be able to answer this question. On 
my NEC 8201 the AC power adapter is rated for 8.5 volts. The AC power adapter 
for my 100/102/200/TPDD2 is 6v. I have both on my desk but get them mixed up at 
times even though I try not to. The units seem happy with either voltage. So 
I'm wondering if there is a risk of damage when I accidentally put the 8.5v 
plug in my 200 or 102. Do they have an internal regulator that prevents damage?
And one other question. I am getting ready to make the modification to my 200 
which allows it to have rechargeable batteries rather than regular AA cells. 
This is an option which the service manual refers to. It involves soldering two 
small jumpers. Will I need to run a higher voltage to charge these batteries or 
is 6v enough?
Kurt

Re: [M100] DVI cable for 102

[Mike Stein]

I thought we'd discussed this to death a few months ago...

I don't know where this idea of a third cable comes from; when I bought my DVI 
brand new many years ago it came with two cables just as the insert shows, one 
with a 40-pin DIP Plug at the computer end for the M100, and another with a 
2x20 male IDC header with swapped conductor pairs for the 102 & 200, both with 
aluminum foil shielding on one side.

At least that's what I have; I suppose it's possible that they supplied 
something different at some time.

As far as I can tell, when they designed the DVI they arranged the pins so that 
it would connect to the M100 with a straight-through cable; unfortunately the 
40-pin DIP connector they chose for the M100 end does not use the 'standard' 
pinout convention, so when they duplicated that pinout in the dual-20 header in 
the 102 and 200 they had to modify the cable to conform to the non-standard 
pinout.

If they'd used a 'standard' DIP plug and arranged the DVI pins to match there 
would not have been a problem; the pinout description in the DVI manual even 
suggests that there might have been some confusion in the design process...

m


  - Original Message - 
  From: Brian White 
  To: m...@bitchin100.com 
  Sent: Thursday, March 15, 2018 5:17 PM
  Subject: Re: [M100] DVI cable for 102


  There is a single sheet insert that came with one of my DVI manuals that 
shows a two-part cable, where I think the deal is there's really 3 total parts, 
one for 100, one for 102 & 200, and one for the DVI.

  I scanned it and uploaded it to Archive.org a few weeks ago. It's a little 
paper about the size of a paperback book. Perhaps these came later along with 
the 100/200 version of the system disk? Maybe the mid-way connector performs 
the twists?

  https://archive.org/details/DVI263806Notice


  I too would like specifically more and clearer pictures of the cables, 
especially the connectors. Not the DVI itself. There are lot's of DVI's out 
there and I have 2 myself. But the original cables are mostly gone and there 
are not really even any pictures of the cables and connectors that are good 
enough to trace the conductors right to the pins, and see all possible 
manufacturing marks, like you could if you had one in your hands one in your 
hands.




  On Thu, Mar 15, 2018 at 12:43 PM, Mike Stein  wrote:

Where did you read about a two-part 100 cable?

Nice pictures but it's hard to tell how many cables there are, what 
connector belongs to which cable, and how you're connecting them.

Does the cable with the male plug that plugs into the 102 and 200 have the 
swapped wires as shown in Brian's Wiki?

m
  - Original Message - 
  From: Chris Kmiec 
  To: m...@bitchin100.com 
  Sent: Thursday, March 15, 2018 7:20 AM
  Subject: Re: [M100] DVI cable for 102


  Looks like what I thought was a 102 cable was just the two-part 100 
cable. I guess reading helps... 






  On Thu, Mar 15, 2018 at 6:02 AM, Chris Kmiec  wrote:

OK, I think I spoke too soon. The DVI is working fine, but I can't get 
any of my 102s to respond, connected to that cable.  


The 100 that came with the DVI has a cable glued on to the bottom from 
the system socket, and same type of connector on the other end as 102 system 
bus. When I connect the 102-looking cable from the DVI and the cable on the 100 
together, everything works together.


I guess I still need a cable for the 102...


On Wed, Mar 14, 2018 at 7:55 PM, Chris Kmiec  wrote:

  :) Ok, maybe not 50, but I'll take some. Here are a few while I'm 
working on cleaning it: 


  https://1drv.ms/f/s!AiOtw8Sr4zlvgaBRTB4K9WCxOOmoeQ



  On Tue, Mar 13, 2018 at 10:39 PM, Brian White  
wrote:

Can you take about 50 very clear pictures of both cables and 
connectors please? :) 


We have the info to create new cables that function, but I still 
would really like to see the details of the original cables & connectors up 
close and clear just for reference.


-- 
bkw


On Tue, Mar 13, 2018, 10:07 PM Chris Kmiec  
wrote:

  Ok, I'm in Tandy 100 heaven right now :) Just got my eBay 
package, and despite horrendous packaging, everything survived. Taking 
inventory, I got a beautiful looking DVI, manual, disk BASIC on 5 1/4" disk, 
and BOTH cables, one for 100 and one for 102! Almost afraid to turn it on, but 
that will have to wait until tomorrow when I have a minute to myself...


  On Mon, Mar 12, 2018 at 9:57 AM, Brian White  
wrote:

The strain relief clip specifically I mean, when you snap all 3 
parts of an idc connector together with no cable, the strain relief bar forms a 
thin slot exactly the size and shape to fit a ribbon cable through. 

Re: [M100] 8K RAM Chip

[Mike Stein]

- Original Message - 
From: "Francesco Messineo" 
To: 
Sent: Friday, March 16, 2018 5:19 AM
Subject: Re: [M100] 8K RAM Chip


On Thu, Mar 15, 2018 at 7:57 PM, Mike Stein  wrote:
>> Hi Frank,
>>
>> How about we split the difference and settle on .73"? 

>Well, I don't know, my 700 mils modules work well, I think the difference is 
>so relevant.

(I guess you meant irrelevant?) That's what I thought, until you brought it 
up... ;-)
---

>> As to using diodes, I've often used this technique...

> I think it can be done, but you anyway need logic to reconstruct the 
> addresses, so why bother with diodes? 

Diodes can be used as logic elements; as a matter of fact, before TTL there was 
DTL (Diode-transistor logic): 
https://en.wikipedia.org/wiki/Diode%E2%80%93transistor_logic

That's how they're used in this case to form three AND gates.
---
>>I use only one logic chip for all the work.

I'm not saying that diodes are a better way of doing it, just that it's a 
different approach used by at least one of the commercial modules.

m

Re: [M100] DVI cable for 102

[Brian White]

On Fri, Mar 16, 2018, 10:11 AM Brian White  wrote:

> Ah! These are good, thank you! Already I can see why you have no twists. I
> won't be able to show you what I mean for a little while but I have
> pictures of at least 5 or 6 different manufactures of dip40 idc connector
> (the blue one in your pics) and I can show how the pins on yours are
> different from all the others.
>

Actually I can show most of what I mean, I can show all the other
connectors as I had previously uploaded those, but I don't have time to
draw on your pic right now to highlight the difference.


https://photos.app.goo.gl/UhRHhuOCz3DtfZl83

-- 
bkw

Re: [M100] DVI cable for 102

[Brian White]

Ah! These are good, thank you! Already I can see why you have no twists. I
won't be able to show you what I mean for a little while but I have
pictures of at least 5 or 6 different manufactures of dip40 idc connector
(the blue one in your pics) and I can show how the pins on yours are
different from all the others.

Mike Stein has previously posted that maker and part number from the blue
one, but although the company still exists, that part is apparantly long
extinct, and the company didn't even answer when I tried to email the
sales/support contact from their web site.

But that could just be because I don't speak whatever language they do.
Their site doesn't have any English version to toggle for instance. Maybe I
should try again only try using google translate to give them something
they can at least read.

So far I have not been able to find any connector with the pin-to-conductor
arrangement like that blue one.

So, at least for now, it looks like there is no better way to make a new
cable today, than the various annoying ways we currently have.

-- 
bkw


On Fri, Mar 16, 2018, 8:55 AM Chris Kmiec  wrote:

> Ok, I lied, sneaked in to take few pix before dinner night out... Enjoy,
> and let me know if you want me to take any other angle!
>
> https://1drv.ms/f/s!AiOtw8Sr4zlvgaBRTB4K9WCxOOmoeQ
>

>

Re: [M100] DVI cable for 102

[Brian White]

Probably someone ends up with 3 cables because probably a single long,
100-only cable (and a 100-only system disk) came with the DVI, and the two
short ones came later with the 100/200 system disk.

On Fri, Mar 16, 2018, 6:57 AM Chris Kmiec  wrote:

> None have any twisted pairs - both the long cable and two short cables
> that connect together are straight through.
>
> Interesting trivia - found a resume on a disk that came with it -
> apparently this unit belonged to a Radio Shack store manager in OH in the
> mid 80s :)
>
> Let me know if you guys need me to take any other pictures, I'll be happy
> to help. And if someone wants to build me a 102 cable, I'll pay for it!
>
> Thanks!
>
> On Thu, Mar 15, 2018 at 10:22 PM, Mike Stein  wrote:
>
>> A *third*cable?!?
>>
>> Do any of them have twisted pairs like this or are they all straight
>> through by any chance?:
>>
>> [image: File:T200 DVI Cable Original Plug 1.jpg]
>>
>>
>>
>>
>> - Original Message -
>>
>> *From:* Chris Kmiec 
>> *To:* m...@bitchin100.com
>> *Sent:* Thursday, March 15, 2018 8:24 PM
>> *Subject:* Re: [M100] DVI cable for 102
>>
>> Ok, I'll get serious with the pictures tomorrow or Saturday.
>>
>> What I have is one cable that's attached to m100, with a custom trap door
>> for the system socket, and that cable is just long enough to stick out 1/4
>> inch out past the back.
>>
>> I have a second cable that connects to that cable, then to the DVI.
>> Together they are only slightly longer than the 3rd cable - from m100
>> socket to DVI.
>>
>> On Mar 15, 2018 5:36 PM, "Mike Stein"  wrote:
>>
>>> Agreed; we need better pictures ;-)
>>>
>>> And yes, the insert is definitely confusing.
>>>
>>> But what's also confusing is that it sounds like it works with an M100
>>> with both cables connected together. I don't see any twists, so I wonder if
>>> maybe someone modified the 102/200 cable to remove the twists and turn it
>>> into an M100 extension; in that case both cables connected together would
>>> work in an M100 but the 102/200 part would not work on the 102.
>>>
>>> (I think; now *I* am getting confused... ;-)
>>>
>>> m
>>>
>>>
>>> - Original Message -
>>> *From:* Brian White 
>>> *To:* m...@bitchin100.com
>>> *Sent:* Thursday, March 15, 2018 5:45 PM
>>> *Subject:* Re: [M100] DVI cable for 102
>>>
>>> Ah, looking at that insert again, I realize it gives all the answers,
>>> except, looking longer, it seems to give wrong answers that don't add up.
>>>
>>> 1) The 2-part cable came with the 200-compatible system disk, and they
>>> both came together as their own package.
>>>
>>> 2) The drawing seems to say that these are really just two separate
>>> cables, not a single two-part cable, and the written directions seem to
>>> agree, it's just that they don't quite say it straight out simply like
>>> that. But if you do what they say, it ends up resolving out to that.
>>>
>>> It's just confusing because of several things:
>>>
>>> * The cables might have shipped connected together, according to the
>>> written directions.
>>> * The drawing looks like one cable with a break with connectors that
>>> mate, the drawing isn't clear enough to show that "the blue connector"
>>> doesn't actually look the same or fit into that other cable right next to
>>> it.
>>> * The directions actually say "the special two-part cable included".
>>>
>>> So, I *think* this is not a two-part cable at all, just simply plain
>>> old, two different cables to work with two different models of computer.
>>> One cable is for 102 & 200, the other cable is for 100, and that's it,
>>> the cables are never supposed to be connected to each other.
>>>
>>> Which is why I'd really like to see some clear full close pics of the
>>> cables and connectors from different angles, because if this is true, then
>>> there should be some funky twists in the wires somewhere, or else these are
>>> funky connectors that don't map the wires to the pins the same way every
>>> other connector in the world does at least today.
>>>
>>>
>>> On Thu, Mar 15, 2018 at 5:17 PM, Brian White  wrote:
>>>
 There is a single sheet insert that came with one of my DVI manuals
 that shows a two-part cable, where I think the deal is there's really 3
 total parts, one for 100, one for 102 & 200, and one for the DVI.
 I scanned it and uploaded it to Archive.org a few weeks ago. It's a
 little paper about the size of a paperback book. Perhaps these came later
 along with the 100/200 version of the system disk? Maybe the mid-way
 connector performs the twists?

 https://archive.org/details/DVI263806Notice

 I too would like specifically more and clearer pictures of the cables,
 especially the connectors. Not the DVI itself. There are lot's of DVI's out
 there and I have 2 myself. But the original cables are mostly gone and
 there are 

Re: [M100] DVI cable for 102

[Chris Kmiec]

Ok, I lied, sneaked in to take few pix before dinner night out... Enjoy,
and let me know if you want me to take any other angle!

https://1drv.ms/f/s!AiOtw8Sr4zlvgaBRTB4K9WCxOOmoeQ

On Thu, Mar 15, 2018 at 7:26 PM, Chris Kmiec  wrote:

> And that's what it appears to be doing - both cables connected work great
> with my m100, but the short DVI to system bus part does not respond to
> anything on my 102.
>
>
> On Mar 15, 2018 5:36 PM, "Mike Stein"  wrote:
>
> Agreed; we need better pictures ;-)
>
> And yes, the insert is definitely confusing.
>
> But what's also confusing is that it sounds like it works with an M100
> with both cables connected together. I don't see any twists, so I wonder if
> maybe someone modified the 102/200 cable to remove the twists and turn it
> into an M100 extension; in that case both cables connected together would
> work in an M100 but the 102/200 part would not work on the 102.
>
> (I think; now *I* am getting confused... ;-)
>
> m
>
>
> - Original Message -
> *From:* Brian White 
> *To:* m...@bitchin100.com
> *Sent:* Thursday, March 15, 2018 5:45 PM
> *Subject:* Re: [M100] DVI cable for 102
>
> Ah, looking at that insert again, I realize it gives all the answers,
> except, looking longer, it seems to give wrong answers that don't add up.
>
> 1) The 2-part cable came with the 200-compatible system disk, and they
> both came together as their own package.
>
> 2) The drawing seems to say that these are really just two separate
> cables, not a single two-part cable, and the written directions seem to
> agree, it's just that they don't quite say it straight out simply like
> that. But if you do what they say, it ends up resolving out to that.
>
> It's just confusing because of several things:
>
> * The cables might have shipped connected together, according to the
> written directions.
> * The drawing looks like one cable with a break with connectors that mate,
> the drawing isn't clear enough to show that "the blue connector" doesn't
> actually look the same or fit into that other cable right next to it.
> * The directions actually say "the special two-part cable included".
>
> So, I *think* this is not a two-part cable at all, just simply plain old,
> two different cables to work with two different models of computer.
> One cable is for 102 & 200, the other cable is for 100, and that's it, the
> cables are never supposed to be connected to each other.
>
> Which is why I'd really like to see some clear full close pics of the
> cables and connectors from different angles, because if this is true, then
> there should be some funky twists in the wires somewhere, or else these are
> funky connectors that don't map the wires to the pins the same way every
> other connector in the world does at least today.
>
>
> On Thu, Mar 15, 2018 at 5:17 PM, Brian White  wrote:
>
>> There is a single sheet insert that came with one of my DVI manuals that
>> shows a two-part cable, where I think the deal is there's really 3 total
>> parts, one for 100, one for 102 & 200, and one for the DVI.
>> I scanned it and uploaded it to Archive.org a few weeks ago. It's a
>> little paper about the size of a paperback book. Perhaps these came later
>> along with the 100/200 version of the system disk? Maybe the mid-way
>> connector performs the twists?
>>
>> https://archive.org/details/DVI263806Notice
>>
>> I too would like specifically more and clearer pictures of the cables,
>> especially the connectors. Not the DVI itself. There are lot's of DVI's out
>> there and I have 2 myself. But the original cables are mostly gone and
>> there are not really even any pictures of the cables and connectors that
>> are good enough to trace the conductors right to the pins, and see all
>> possible manufacturing marks, like you could if you had one in your hands
>> one in your hands.
>>
>>
>> On Thu, Mar 15, 2018 at 12:43 PM, Mike Stein  wrote:
>>
>>> Where did you read about a two-part 100 cable?
>>>
>>> Nice pictures but it's hard to tell how many cables there are, what
>>> connector belongs to which cable, and how you're connecting them.
>>>
>>> Does the cable with the male plug that plugs into the 102 and 200 have
>>> the swapped wires as shown in Brian's Wiki?
>>>
>>> m
>>>
>>> - Original Message -
>>> *From:* Chris Kmiec 
>>> *To:* m...@bitchin100.com
>>> *Sent:* Thursday, March 15, 2018 7:20 AM
>>> *Subject:* Re: [M100] DVI cable for 102
>>>
>>> Looks like what I thought was a 102 cable was just the two-part 100
>>> cable. I guess reading helps...
>>>
>>>
>>>
>>> On Thu, Mar 15, 2018 at 6:02 AM, Chris Kmiec  wrote:
>>>
 OK, I think I spoke too soon. The DVI is working fine, but I can't get
 any of my 102s to respond, connected to that cable.

 The 100 that came with the DVI has a cable glued on to the bottom from
 the system socket, and same type 

Re: [M100] DVI cable for 102

[Chris Kmiec]

None have any twisted pairs - both the long cable and two short cables that
connect together are straight through.

Interesting trivia - found a resume on a disk that came with it -
apparently this unit belonged to a Radio Shack store manager in OH in the
mid 80s :)

Let me know if you guys need me to take any other pictures, I'll be happy
to help. And if someone wants to build me a 102 cable, I'll pay for it!

Thanks!

On Thu, Mar 15, 2018 at 10:22 PM, Mike Stein  wrote:

> A *third*cable?!?
>
> Do any of them have twisted pairs like this or are they all straight
> through by any chance?:
>
> [image: File:T200 DVI Cable Original Plug 1.jpg]
>
>
>
>
> - Original Message -
>
> *From:* Chris Kmiec 
> *To:* m...@bitchin100.com
> *Sent:* Thursday, March 15, 2018 8:24 PM
> *Subject:* Re: [M100] DVI cable for 102
>
> Ok, I'll get serious with the pictures tomorrow or Saturday.
>
> What I have is one cable that's attached to m100, with a custom trap door
> for the system socket, and that cable is just long enough to stick out 1/4
> inch out past the back.
>
> I have a second cable that connects to that cable, then to the DVI.
> Together they are only slightly longer than the 3rd cable - from m100
> socket to DVI.
>
> On Mar 15, 2018 5:36 PM, "Mike Stein"  wrote:
>
>> Agreed; we need better pictures ;-)
>>
>> And yes, the insert is definitely confusing.
>>
>> But what's also confusing is that it sounds like it works with an M100
>> with both cables connected together. I don't see any twists, so I wonder if
>> maybe someone modified the 102/200 cable to remove the twists and turn it
>> into an M100 extension; in that case both cables connected together would
>> work in an M100 but the 102/200 part would not work on the 102.
>>
>> (I think; now *I* am getting confused... ;-)
>>
>> m
>>
>>
>> - Original Message -
>> *From:* Brian White 
>> *To:* m...@bitchin100.com
>> *Sent:* Thursday, March 15, 2018 5:45 PM
>> *Subject:* Re: [M100] DVI cable for 102
>>
>> Ah, looking at that insert again, I realize it gives all the answers,
>> except, looking longer, it seems to give wrong answers that don't add up.
>>
>> 1) The 2-part cable came with the 200-compatible system disk, and they
>> both came together as their own package.
>>
>> 2) The drawing seems to say that these are really just two separate
>> cables, not a single two-part cable, and the written directions seem to
>> agree, it's just that they don't quite say it straight out simply like
>> that. But if you do what they say, it ends up resolving out to that.
>>
>> It's just confusing because of several things:
>>
>> * The cables might have shipped connected together, according to the
>> written directions.
>> * The drawing looks like one cable with a break with connectors that
>> mate, the drawing isn't clear enough to show that "the blue connector"
>> doesn't actually look the same or fit into that other cable right next to
>> it.
>> * The directions actually say "the special two-part cable included".
>>
>> So, I *think* this is not a two-part cable at all, just simply plain old,
>> two different cables to work with two different models of computer.
>> One cable is for 102 & 200, the other cable is for 100, and that's it,
>> the cables are never supposed to be connected to each other.
>>
>> Which is why I'd really like to see some clear full close pics of the
>> cables and connectors from different angles, because if this is true, then
>> there should be some funky twists in the wires somewhere, or else these are
>> funky connectors that don't map the wires to the pins the same way every
>> other connector in the world does at least today.
>>
>>
>> On Thu, Mar 15, 2018 at 5:17 PM, Brian White  wrote:
>>
>>> There is a single sheet insert that came with one of my DVI manuals that
>>> shows a two-part cable, where I think the deal is there's really 3 total
>>> parts, one for 100, one for 102 & 200, and one for the DVI.
>>> I scanned it and uploaded it to Archive.org a few weeks ago. It's a
>>> little paper about the size of a paperback book. Perhaps these came later
>>> along with the 100/200 version of the system disk? Maybe the mid-way
>>> connector performs the twists?
>>>
>>> https://archive.org/details/DVI263806Notice
>>>
>>> I too would like specifically more and clearer pictures of the cables,
>>> especially the connectors. Not the DVI itself. There are lot's of DVI's out
>>> there and I have 2 myself. But the original cables are mostly gone and
>>> there are not really even any pictures of the cables and connectors that
>>> are good enough to trace the conductors right to the pins, and see all
>>> possible manufacturing marks, like you could if you had one in your hands
>>> one in your hands.
>>>
>>>
>>> On Thu, Mar 15, 2018 at 12:43 PM, Mike Stein 
>>> wrote:
>>>
 Where did you read about a two-part 100 cable?

[M100] Model 100 Backup Battery Replacement

[Paul Sussman]

Can anyone please recommend a source for the correct internal backup battery 
for the M100? I want to be sure I purchase the correct one.

 

Thanks,

Paul

 

Paul

 

Re: [M100] DVI cable for 102

[Brian White]

There is a single sheet insert that came with one of my DVI manuals that
shows a two-part cable, where I think the deal is there's really 3 total
parts, one for 100, one for 102 & 200, and one for the DVI.
I scanned it and uploaded it to Archive.org a few weeks ago. It's a little
paper about the size of a paperback book. Perhaps these came later along
with the 100/200 version of the system disk? Maybe the mid-way connector
performs the twists?

https://archive.org/details/DVI263806Notice

I too would like specifically more and clearer pictures of the cables,
especially the connectors. Not the DVI itself. There are lot's of DVI's out
there and I have 2 myself. But the original cables are mostly gone and
there are not really even any pictures of the cables and connectors that
are good enough to trace the conductors right to the pins, and see all
possible manufacturing marks, like you could if you had one in your hands
one in your hands.


On Thu, Mar 15, 2018 at 12:43 PM, Mike Stein  wrote:

> Where did you read about a two-part 100 cable?
>
> Nice pictures but it's hard to tell how many cables there are, what
> connector belongs to which cable, and how you're connecting them.
>
> Does the cable with the male plug that plugs into the 102 and 200 have the
> swapped wires as shown in Brian's Wiki?
>
> m
>
> - Original Message -
> *From:* Chris Kmiec 
> *To:* m...@bitchin100.com
> *Sent:* Thursday, March 15, 2018 7:20 AM
> *Subject:* Re: [M100] DVI cable for 102
>
> Looks like what I thought was a 102 cable was just the two-part 100 cable.
> I guess reading helps...
>
>
>
> On Thu, Mar 15, 2018 at 6:02 AM, Chris Kmiec  wrote:
>
>> OK, I think I spoke too soon. The DVI is working fine, but I can't get
>> any of my 102s to respond, connected to that cable.
>>
>> The 100 that came with the DVI has a cable glued on to the bottom from
>> the system socket, and same type of connector on the other end as 102
>> system bus. When I connect the 102-looking cable from the DVI and the cable
>> on the 100 together, everything works together.
>>
>> I guess I still need a cable for the 102...
>>
>> On Wed, Mar 14, 2018 at 7:55 PM, Chris Kmiec  wrote:
>>
>>> :) Ok, maybe not 50, but I'll take some. Here are a few while I'm
>>> working on cleaning it:
>>>
>>> https://1drv.ms/f/s!AiOtw8Sr4zlvgaBRTB4K9WCxOOmoeQ
>>>
>>> On Tue, Mar 13, 2018 at 10:39 PM, Brian White 
>>> wrote:
>>>
 Can you take about 50 very clear pictures of both cables and connectors
 please? :)

 We have the info to create new cables that function, but I still would
 really like to see the details of the original cables & connectors up close
 and clear just for reference.

 --
 bkw

 On Tue, Mar 13, 2018, 10:07 PM Chris Kmiec  wrote:

> Ok, I'm in Tandy 100 heaven right now :) Just got my eBay package, and
> despite horrendous packaging, everything survived. Taking inventory, I got
> a beautiful looking DVI, manual, disk BASIC on 5 1/4" disk, and BOTH
> cables, one for 100 and one for 102! Almost afraid to turn it on, but that
> will have to wait until tomorrow when I have a minute to myself...
>
> On Mon, Mar 12, 2018 at 9:57 AM, Brian White 
> wrote:
>
>> The strain relief clip specifically I mean, when you snap all 3 parts
>> of an idc connector together with no cable, the strain relief bar forms a
>> thin slot exactly the size and shape to fit a ribbon cable through.
>>
>> I use that to flip 2 wires over, inser into slot, flip next 2 wires,
>> insert into slot, ... until all 20 pairs are in the slot. Then get them 
>> all
>> into the male connector and crimp it. Then pick apart, or just break off
>> the female connector that was just used as a jig to hold the wires in 
>> place.
>>
>> --
>> bkw
>>
>> On Mon, Mar 12, 2018, 10:50 AM Brian White 
>> wrote:
>>
>>> http://tandy.wiki/Disk/Video_Interface
>>>
>>> It's a pain but it's doable.
>>>
>>> The pictures there don't show the process, only the final result
>>> unfortunately. I used a sacrificial 40pin female idc connector with the
>>> strain relief clip as a guide to hold all the split & twisted  wires 
>>> into a
>>> flat ribbon so that you can get them all arranged into the male 40pin 
>>> idc
>>> connector. I use a Panavise to crimp, not any official crimping tool.
>>>
>>> But by clicking on the pics to get the full size ones, you can see
>>> what you need to do.
>>>
>>> On Mon, Mar 12, 2018, 7:44 AM Chris Kmiec  wrote:
>>>
 Just snagged a DVI off of eBay, and my understanding is that it
 needs a different cable between 100 and 102. Since the auction has a 
 100
 bundled, I 

Re: [M100] 8K RAM Chip

[Francesco Messineo]

On Thu, Mar 15, 2018 at 7:57 PM, Mike Stein  wrote:
> Hi Frank,
>
> How about we split the difference and settle on .73"? Try putting a 16-pin 
> DIP (which should be .700" end to end) into a RAM module socket sideways and 
> I think you'll find that it's a little too short; if you use .1" perfboard 
> you'll have to bend the pins a bit.

Well, I don't know, my 700 mils modules work well, I think the
difference is so relevant.

>
> In any case, the socket spacing is at least .100" wider than the RAM chip.
>
> As to using diodes, I've often used this technique but I must confess that I 
> never measured the standby current. But I don't quite see why that should 
> keep it out of the standby region; with a pull-up resistor and no selects 
> pulling down the diodes /CE should be at Vcc.

I think it can be done, but you anyway need logic to reconstruct the
addresses, so why bother with diodes? I use only one logic chip for
all the work.

>
> Also, at least one of the commercial modules used diodes, so perhaps it 
> depends on the RAM chip; some experimentation might be in order.
>
> m
>
>
>
> - Original Message -
> From: "Francesco Messineo" 
> To: 
> Sent: Thursday, March 15, 2018 1:27 PM
> Subject: Re: [M100] 8K RAM Chip
>
>
> On Thu, Mar 15, 2018 at 6:08 PM, Mike Stein  wrote:
>> Yeah, there are a number of ways to deal with the non-standard RAM modules
>> in an M100; the pin spacing of the modules is .75 instead of the standard
>> .60, so you will probably have to make a little adapter board in any case.
>>
> spacing is actually 700 mils
>
>> A self-contained module has to combine the four discrete chip selects into
>> one, and also re-encode them into the binary upper two addresses. There are
>> various ways of doing that and I have some of the commercial circuits
>> somewhere but can't find them at the moment.
>>
>> One way would be a priority encoder as Fugu suggests. His 32K idea is clever
>> and you could just used diodes to combine the chip selects; as a matter of
>> fact you can also use an 8K chip and use diodes for the encoding instead of
>> the encoder IC.
>
> A word of warning about using diodes to combine the selects: all the
> low power cmos rams need close to Vdd or Vss levels on the select to
> have the lowest current consumption when in sleep mode (Vdd circa 3V
> inside the M100).
> If the ram chip doesn't go in the correct standby mode, the internal
> battery of the M100 is drained in about one day instead of the usual
> one month (tests done in my Olivetti M10 several times).
>
>
> Frank
>>
>> - Original Message -
>> From: Fugu ME100
>> To: m...@bitchin100.com
>> Sent: Wednesday, March 14, 2018 5:14 PM
>> Subject: Re: [M100] 8K RAM Chip
>>
>> If you did not want to use the Libero method you could use a 74HC148 (or
>> similar) 8 to 3 line priority decoder and put the 4 CSx- lines into the
>> upper or lower 4 inputs of the ‘148. That would recreate 2 address lines and
>> a new CS- for the 8Kx8 SRAM.  It could all mount on a proto-board and not
>> require any 'soldering to' the M100 :)  I would guess the NEC board uses a
>> similar method but with an HC149 8-to-8 line priority encoder.
>>
>> Alternatively use a 32Kx8 SRAM and waste 3/4 of the space, but it would
>> still need the CSx- lines ANDed to generate the SRAM CS-. Again no soldering
>> on the M100 required.
>>
>>
>>
>> From: M100  on behalf of Mike Stein
>> 
>> Reply-To: 
>> Date: Wednesday, March 14, 2018 at 12:19 PM
>> To: 
>> Subject: Re: [M100] 8K RAM Chip
>>
>> It needs more than just remapping the signals; the required upper two
>> address lines are not available on the sockets so you either need to add
>> logic to recreate them or modify the main board.
>>
>> m
>>
>> - Original Message -
>> From: Gregory McGill
>> To: m...@bitchin100.com
>> Sent: Wednesday, March 14, 2018 1:22 PM
>> Subject: Re: [M100] 8K RAM Chip
>>
>> thanks! It seems like we should be able to use the 8x8 chip from the 102
>> with some kludging of lines.. they are pretty close..
>>
>> Greg
>>
>> On Wed, Mar 14, 2018 at 10:08 AM, Brian White  wrote:
>>>
>>> There are at least a few different "build your own ram upgrade" articles
>>> on club100 and other archives of old forum posts, and in magazines too I
>>> think but those are hard to search.
>>>
>>> Here's one that is not one of the old original ones I was thinking of, but
>>> looks ok.
>>>
>>> http://digilander.libero.it/rar2k/TRS80/Memory24k.html
>>>
>>> I have some NEC modules that work that I assume must have originally been
>>> meant for nec 8201a. They are a little pcb with a single ram chip and an
>>> additional chip probably a decoder of some sort to consume 4 chip-enable
>>> lines. I could take some photos of it and maybe it's circuit could be
>>> reverse engineered 

Re: [M100] 8K RAM Chip

[Daryl Tester]

Geez guys, can you trim your emails, especially if you're receiving
the list in digest mode?

On 16/03/18 05:43, Fugu ME100 wrote:

Hi Frank

How did you perform the current drain tests?

Anyone know of a source for 700mil IC Sockets? Thanks!

On 15/3/18, 10:27 AM, "M100 on behalf of Francesco Messineo"
 wrote:


On Thu, Mar 15, 2018 at 6:08 PM, Mike Stein  wrote:






--
Regards,
 Daryl Tester
 Handcrafted Computers Pty. Ltd.