[M100] Tandy 200 power button replacement

[Josh Malone]

All,

I've finally managed to acquire a model 200 system! ... and there was
much rejoicing...
It's in pretty good condition, other than being from a smoker's home.
But, the power button switch is missing the plunger entirely. I can
power the system up and down by shorting the contacts with a
screwdriver, but that's no way to live. :)

The T200 tech ref lists an obscure and uncrossable part number for
this switch. Does anybody know of a suitable modern replacement? It
looks like I should be able to drop an normally-open momentary switch
in there - but has anybody found one that works physically in the case
and PCB?

Thanks,

-Josh

Re: [M100] nn - getting back involved.

[Mike Stein]

- Original Message - 
From: "Nickolas Nolan" 
To: ; 
Sent: Wednesday, June 27, 2018 11:35 AM
Subject: Re: [M100] nn - getting back involved.
...
> The reference I have for the model 102 is here http://tandy.wiki/FigTronix
> again, I'm not sure how much of that documentation is correct, and I will try 
> to look at a few more units from my trunk this weekend. I've been meaning to 
> attempt a dump of my SuperRom in my 102.



For replacing the non-standard System ROM in an older (pre-12/83) M100 you 
might want to also look at this adapter:
https://www.oshpark.com/shared_projects/Kil9S1ya

Unlike the FigTronix this one does not require desoldering the socket or any 
modifications to the M100, uses a standard DIP 27C256 EPROM, and it is 
reprogrammable.

As a bonus you can optionally combine an option ROM image with the system ROM 
using a 27C512 instead of the '256; this precludes using the option ROM socket 
for an additional 'normal' option ROM or indeed anything that normally plugs 
into the option ROM socket such as the REX etc., although you could install a 
switch to disable it.

m

Re: [M100] nn - getting back involved.

[Jim Anderson]

> -Original Message-
> 
> Setting aside of course the other option which is that there is a way to
> use a REX to not only replace the main rom, but have a fully software
> hackable main rom after that once it's installed. But that requires
> installing the rex a little more permanently than usual.

I've done it both on my M100 and my T200 - I even made a plug out of a short 
row of pin headers with all but the two end pins removed, and then bent over to 
make a 90-degree plug that fits into TP1 and TP2 on the REX so that you can 
remove it and swap for another REX without fishing the wires back out of the 
machine.  (Of course, you can't remove the REX entirely without opening up the 
machine to put the original ROMs back in their sockets, but you can't have 
everything...)

It's a much more accessible way for someone like me to mess around with 
different ROMs without having to go invest time and money in setting myself up 
for burning my own ROM chips.







jim

Re: [M100] nn - getting back involved.

[Brian White]

This will get a little confusing because we're talking about both main rom
and option rom at the same time, so watch for that the rest of this post.

The 100, 102, 200, 600, NEC all use 27C256, both for main rom and option
rom *electrically*, but, in most cases the pinouts are rearranged. And it's
not the same rearranging in all cases either.

In most (not all) 100s main rom, and in all 100, 102, 200, nec option rom,
the pinout is rearranged.

Some late model 100s, all 102, 200, and 600, (not sure about nec), main rom
uses normal pinout.

Model 600 is the only one I know that uses normal pinout in the option rom
socket.

Also, the rearranged pinout for Model 100 main rom is different from the
rearranged pinout for the option rom!

But at least the option rom pinout is the same between all 100, 102, and
200, and I think nec too.

(I don't have an nec and haven't look it up so really every time I'm trying
to say "they all do X except one does Y..." I can't say if nec is included
or another exception)

The figtronix adapter boards are a little odd. The option rom adapters use
28C256 instead of 27C256, so that you can re-flash them without a UV eraser.

One of the main rom adapters actually uses 28F256, instead of 28C256 or
27C256. I'm not sure why, but it works. 28F256 is a different pinout from
28C256 or 27C256, but electrical and signal compatible. I used it on a
couple 100s. I liked it because it makes the main rom both removable and
easily re-flashable because it can be removed from the pinout adapter, but
it's hard to recommend, because it does require desoldering the original
dip28 socket to make enough room for the new adapter and tall through-hole
style plcc socket.

It probably makes more sense all in all, to use the Mike Stein main rom
adapter, which uses a plain dip28 27C256, with the new rom soldered to the
adapter, and the combined module inserted in the original socket. Because
that preserves the original mother board, and it is still physically
possible to remove and update the main rom, you just need to make up a
programming adapter to reverse the adapter pinout back to normal, or use a
test clip to clip right on to the rom but those test clips are getting hard
to find. You can't have both the original socket on the motherboard and a
socket on the adapter. There isn't room in the case.

Setting aside of course the other option which is that there is a way to
use a REX to not only replace the main rom, but have a fully software
hackable main rom after that once it's installed. But that requires
installing the rex a little more permanently than usual.

-- 
bkw

On Wed, Jun 27, 2018, 11:35 AM Nickolas Nolan 
wrote:

> Hi Brian,
>
> I'm not sure how much information is conflicting here.
> I was under the impression for 102, and I know for sure regarding NEC that
> the roms are 27c256 map.
> I have been dumping and burning my own for NEC 8201a and 8300. They don't
> even need carriers. SPEAKING OF :) i will start another thread or two
> for something else.
>
> The reference I have for the model 102 is here http://tandy.wiki/FigTronix
> again, I'm not sure how much of that documentation is correct, and I will
> try to look at a few more units from my trunk this weekend. I've been
> meaning to attempt a dump of my SuperRom in my 102.
>
> I am also hoping to find or make OSH park print for model100 static ram to
> compliment https://oshpark.com/shared_projects/m3Ugar47
>
> I look forward to verifying as much as possible, and I will attempt
> contact the tandy.wiki owner if there are any corrections.
>

Re: [M100] M100 Digest, Vol 90, Issue 21

[Nickolas Nolan]

I have an interesting NEC PC-8300 with a custom 2NDROM by VSI Corp. I figured 
I'd put together a few images in case someone's as curious as I am.

Previously attempted to send as an attachment. Here is a google drive post 
instead.
https://drive.google.com/open?id=1w7hzeDeT7mQNhpwPX9Y8bbHjtluwC7Ae

> On June 26, 2018 at 4:39 PM m100-requ...@lists.bitchin100.com wrote:
>
>
> Send M100 mailing list submissions to
> m100@lists.bitchin100.com
>
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> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of M100 digest..."
>
>
> Today's Topics:
>
> 1. Re: nn - getting back involved. (Brian White)
> 2. NEC Low battery light update (Kurt McCullum)
>
>
> --
>
> Message: 1
> Date: Tue, 26 Jun 2018 03:08:35 -0400
> From: Brian White 
> To: m...@bitchin100.com
> Subject: Re: [M100] nn - getting back involved.
> Message-ID:
> 
> Content-Type: text/plain; charset="utf-8"
>
> I have about 100 of the old original carriers if anyone wants any. The
> carriers aren't really that useful or valuable since, aside from the fact
> that they are replaceable by printing (2 different versions even) only the
> Model 600 uses a standard 27C256 pinout in the option rom socket. For 100,
> 102, & 200, the only thing a carrier is good for is if you broke an
> original carrier on a real option rom with the borkded pinout.
>
> For model 600, you can burn a standard 27C256 and stick it in a carrier and
> pop it in the 600. So the carriers are useful for Model 600.
> But there is almost no romware to play with and little documentation to
> make some from scratch for the 600.
> There are exactly 2 rom images available to be examined and hacked on, and
> a little bit of info on the format of a rom, but I think not quite enough.
>
> For burning your own roms on anything but 600, you need a module like REX
> or Figronix or ROMBO which don't fit in a carrier. They are their own
> carrier and go right into the socket.
>
> (Unless the NECs also use a standard pinout? I don't have one to double
> check.)
>
> Now the *sockets* are a little more interesting because:
> * you could repair a damaged socket in a 100/102/200/600/NEC
> * you can use one as part of a programming adapter for re-flashing a
> Figtronix module in an eprom burner
> * using same programming adapter to read an old option rom in a eprom burner
> * as a jig to supply power to a REX while flashing it's CPLD (IE, while
> building your own REX from scratch, or perhaps reflashing it from 100/102
> to 200 firmware)
>
> I have a bunch of those too and am handing them out in ones/twos to anyone
> who wants one for free.
> I'm not selling them, just handing them out, so that I can dribble them out
> to as many different people as possible for as long as possible.
> I don't have an absolte rule like "max 2 per person" but that's the limit
> I've been doing so far. But I'm open to hearing why someone might need a
> few more . Like say you are repairing M100's for other people and it would
> be useful stock for doing that, or you actually have 3 or more M100's with
> broken sockets, or whatever.
>
> --
> bkw
>
>
> On Mon, Jun 25, 2018 at 3:18 PM Josh Malone  wrote:
>
> > > ps: Are there any other club100 peeps on the east coast?
> >
> > Central Virginia in the house! :)
> >
> > And I'd probably be down for a couple chip carriers even though I have
> > a REX. Lemme know.
> >
> > -Josh
> >
>
>
> --
> bkw
> -- next part --
> An HTML attachment was scrubbed...
> URL: 
> 
>
> --
>
> Message: 2
> Date: Tue, 26 Jun 2018 09:06:21 -0700
> From: Kurt McCullum 
> To: m100@lists.bitchin100.com
> Subject: [M100] NEC Low battery light update
> Message-ID:
> <1530029181.3369499.1421060320.66fe2...@webmail.messagingengine.com>
> Content-Type: text/plain; charset="utf-8"
>
> A couple weeks ago I was asking about the low battery light on my NEC when 
> using rechargeable batteries. The problem was that after about 45 minutes the 
> low battery light would come on because the voltage difference (1.2 vs 1.5) 
> of Alkaline vs NiMh batteries. Originally I was going to look at the 
> power?supply itself to see if I could replace a resistor so that the light 
> would come on at a lower voltage. I opted to leave the power supply alone and 
> focus on the battery.
>
> I bought?ten 1/3AA NiMh batteries and built a battery pack. There are two 
> banks of five 1/3AA batteries and two spacers(S1 & S2). The ending battery 
> pack looks like this:
> + -
> | S1 S2 

Re: [M100] nn - getting back involved.

[Gregory McGill]

I sell both already assembled and tested on arcadeshopper.com

On Wed, Jun 27, 2018 at 9:00 AM Fugu ME100  wrote:

> 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] 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] nn - getting back involved.

[Nickolas Nolan]

Hi Brian,

I'm not sure how much information is conflicting here.
I was under the impression for 102, and I know for sure regarding NEC that the 
roms are 27c256 map.
I have been dumping and burning my own for NEC 8201a and 8300. They don't even 
need carriers. SPEAKING OF :) i will start another thread or two for 
something else.

The reference I have for the model 102 is here http://tandy.wiki/FigTronix
again, I'm not sure how much of that documentation is correct, and I will try 
to look at a few more units from my trunk this weekend. I've been meaning to 
attempt a dump of my SuperRom in my 102.

I am also hoping to find or make OSH park print for model100 static ram to 
compliment https://oshpark.com/shared_projects/m3Ugar47

I look forward to verifying as much as possible, and I will attempt contact the 
tandy.wiki owner if there are any corrections.