[M100] low VEE voltage - help me?

[Jim Anderson]

Hi,

My first M100 died on me about two years ago with a problem where the VEE 
supply voltage is low (between -1.4 and -1.7 volts, instead of the expected 
-5v).  At the time I posted here and the best guesses centered around one or 
more bad capacitors, particularly C85.  I did get around to removing C85 at the 
time and it did have a tiny amount of fuzzy crud on the bottom around the 
leads.  I put the whole thing aside and swapped in a motherboard from another 
parts machine.

Fast forward to this year, after continuously putting off ordering the 
capacitors from digikey, I finally ordered several capacitor replacement kits 
and nimh memory batteries from arcadeshopper and today sat down to re-cap this 
motherboard.  Well, it seems maybe I should have started with a different 
machine because all I've done is blow a few hours and frustrate myself.  I 
checked after replacing C85 and VEE was still only -1.7 volts, so I soldiered 
on in the vain hope that maybe another bad cap was at fault - replaced all the 
caps and sure enough it was still only -1.7 volts when I was done.  :(

VDD is correct (+4.97 volts) and the memory nimh is charging when power is 
connected (voltage at the battery rises).  I'm testing the motherboard without 
the lcd or keyboard connected as I'm pretty sure it's supposed to be able to 
make -5v on VEE without those components connected...

I'm not really familiar with expected diode test values, but to give you guys 
some additional info to go on (in case any of these are bad) I lifted one end 
on each of D13, D14, and D15 to test them, measured 0.22, 0.73, and 0.54 volts 
forward drop respectively and open circuit in reverse.  I don't know if those 
are appropriate values.  I also checked R97 and it is 180 ohms as expected.

Help!!!  I feel like I've been banging my head against the wall all evening. 







jim

Re: [M100] WP-2

[Brian White]

The last piece I as waiting for came in today and the ram card works both
mechanically and functionally.

Based on what I learned today I have some final cleanup and updates to do,
so don't actually order any of the boards currently on github. (I'm leaving
the note at the top saying "do not use yet")

But, the board labelled "v003" works with SRAM such as CY62128, the Samtec
pin socket, and the "v003-s" 3d printed carrier.

It works both with and without the cap & resistors.

 The cap preserves the ram if you unplug the card while the machine is on,
but not if you leave the card inserted and turn the machine off. It must be
draining into the machine. I either need to add some form of backfeed
protection like at least a diode, or just scrap the whole complication and
just have a simple board with just the chip.

The machine does not recognize more than 128K ram even with a 256K sram
installed and the A17 line connected. And I cannot get both sram and flash
footprints on the board at the same time (without making the board bigger
to make room for more traces). And I have determined that the cheap
ebay/aliexpress pin header isn't usable. So that eliminates several
possible alternative options and configurations and complications I can
just remove, and be left with a simpler set of directions and parts.

So what I'm doing now is tidy up the board to remove the A17 line and the
silkscreen text from saying anything about rom or 256k, and this board will
just be 128K RAM.

And I made a separate ROM version that uses a 39SF020 or 29EE020 etc flash
chip in place of the sram, and a programming adapter for the ROM version to
program it. That version does need a single resistor for /WE besides the
flash chip itself.

None of these updates are on github yet but will be shortly.

-- 
bkw

On Sat, Oct 10, 2020, 7:02 PM Brian White  wrote:

> I'm working on a diy expansion card you'll be able to make yourself. It's
> not ready yet but getting close. I'm currently waiting for my latest pcb
> version to come in, and a better type of pin header.
>
> The latest version 3d-printed part has come in and it checks out.
>
>
> http://github.com/bkw777/WP-2_IC_Card
>
> On Sat, Oct 10, 2020, 6:45 PM  wrote:
>
>> D.
>>
>> I also just bought a WP-2 a couple of weeks ago off eBay as well.  For
>> the battery, I ordered the correct ones (buy lots since like the 100 it is
>> how the ram is saved, but I later found out any 3v coin cell will work. If
>> its smaller just add some cardboard to fill the space.
>>
>> As for the extra internal memory, the only way to know is to open it up,
>> at least that is what I did.  Order a chip, was $6 with shipping off eBay,
>> was worth it to just know you have extra memory (1PCS Hitachi HM628128DLP-5
>> HM628128 628128 128K CMOS SRAM DIP32 is the listing on eBay, and can
>> confirm it works came fast as well) but it is used just as a ram disk.
>> Guess that would be how to check without openning it, if the ram disk is an
>> option to save then it has the chip.  There's a YouTube video that shows
>> how to install I think.
>>
>> As for the memory cards, I read they are almost impossible to find, with
>> the extra internal ram disk they really are not as important.  The nice
>> thing is after getting batteries and a chip your pretty much set, can use
>> the same cassette and cord from the 100 as well, and the power cord as well.
>>
>> Fun little machine, and nice that it has true spell checking.
>>
>> Here's a few links with the manual and some other good info:
>>
>>
>> https://munk.org/typecast/2020/09/09/tandy-wp-2-user-manual-happy-septandy/
>>
>> http://fervor.net/index.php/tag/tandy-wp-2/
>>
>> http://www.bitchin100.com/wiki/index.php?title=Tandy_WP-2_DocGarden
>>
>> Enjoy,
>> Mark
>>
>>
>>
>> On Oct 10, 2020 5:48 PM, dano none  wrote:
>>
>>
>>
>> Hi All,
>>
>>
>>  I purchased a wp-2 off of ebay. One of the nice things about buying a
>> wp-2, is you can justify the use of space, by just telling yourself..
>>
>>  All I have to do, is get rid of one hard back book! =)
>>
>>
>>
>>   Assuming a sympathetic audience on the 100 mailing list I have some
>> questions, I've not seen answered on the club 100 site, or I don't know
>> where to look.
>>
>>
>>When I received the unit, the 2430 backup battery was dead. I've
>> ordered one, but it will take a week, and stopping by my local Radio Shack
>> (tm) isn't an option. I do have a low battery backup indicator and the
>> screen flashes, which makes trying to use it really annoying.
>>
>>
>> 1) How does one check to see if the extra ram is installed?
>>
>> a) If no extra ram is installed, does this take a standard ram
>> chip?
>>
>>
>>  2) There is a space on the side of a memory card.
>>
>>  a) Is this some sort of special memory pin out or something more
>> common like PCMCIA?
>>
>>
>> Thanks,
>>
>> d.
>>
>>
>>

Re: [M100] DLPlus or mComm for macOS 10.15.x

[Joshua O'Keefe]

On Oct 14, 2020, at 5:13 PM, Joshua O'Keefe  wrote:
> I'll try mComm after dinner.  I unpacked the .deb back when it was released 
> and have it lying around somewhere.

Apologies for replying to myself, but I have successfully run Python mComm on 
macOS Catalina 10.15.  It took a bit of doing:

Predicate to this: having a sane python install (I use homebrew); maybe you can 
make it work with system python but I'm allergic to system python on OS X.

ar x mComm_1.2_all.deb # open up the deb, note command is not tar
tar xvf data.tar.xz # extract the contents
cd usr/share/mcomm # get in there to the script
virtualenv venv # create a venv for its dependencies, optional if you don't use 
virtualenv
source venv/bin/activate # activate the venv
pip3 install pyserial # this is the module it needs
python3 ./mcomm.py --path="${HOME}/model100/stash" 
--port=/dev/tty.usbserial-A1084AEN # your parameters will differ

You may want to install it somewhere more permanent.  I tested with the script 
where it lay in my downloads directory but against my real M100 data set.

Re: [M100] DLPlus or mComm for macOS 10.15.x

[Joshua O'Keefe]

I just built dlplus from bkw's master branch and while it did emit some 
compiler warnings, it built and runs out of the box perfectly on macOS Catalina 
10.15.

I'll try mComm after dinner.  I unpacked the .deb back when it was released and 
have it lying around somewhere.

Re: [M100] DLPlus or mComm for macOS 10.15.x

[Brian White]

All 3 of LaddieAlpha, the python version of mComm, and dlplus probably work.

I have used Laddie and dlplus on macos myself, so those 2 I can say for
sure.

I built dlplus on macos a year or two ago and it worked normally. I use
macports for the gcc/gnu environment. I don't like brew but it probably
works in brew also.

But this was a couple years ago using the version from the zip file on
bitchin100 not the newer version at github/bkw777

The newer version might have some linux-isms by now. IE there are a few
system() commands that run commands like "ls" etc, and it installs some
resource files in /usr/local/share. I don't know if that still works on
macos.

It probably "just works" just like always since it's just plain c and not
doing anything special or weird, but I haven't actually tried it recently.

-- 
bkw

On Wed, Oct 14, 2020, 11:27 AM Greg Swallow  wrote:

> All,
>
> Most of my old, Core2Quad and earlier, computers are starting to have
> issues with the latest openSuse and I am looking to going all macOS. Or,
> close to all. My brother-in-law handed his old MacBook Pro CoreDuo done to
> me and I have found use for it as it runs software I have for my PowerMac
> G5. Was able to pickup aMid-2012 MacBook Pro i7 for a song and am wondering
> if anyone has had luck with DLPlus or mComm on macOS?
>
> I have 10.6.8 Snoiw Leopard on the CoreDuo and 10.15.7 Catalina on the i7.
>
> God Bless,
>
> GregS <><

Re: [M100] DLPlus or mComm for macOS 10.15.x

[John R. Hogerhuis]

LaddieAlpha and DLPlus are the options.

I've never found installing Mono on OSX to be a big deal but I haven't done
it for a while.

The advantage of LaddieAlpha is it's already built and you don't need to
set up a compiler.

Guess I should try compiling and running it on .net core. That's cross
platform and supported by microsoft.

-- John.

Re: [M100] DLPlus or mComm for macOS 10.15.x

[Kurt McCullum]

Greg,

There is no native version of mComm for macOS. There is a Python version that 
works under Linux but I have no idea if that would actually work under maxOS.

I think LaddieAlpha is your best bet.

Kurt

On Wed, Oct 14, 2020, at 8:27 AM, Greg Swallow wrote:
> All,
> 
> Most of my old, Core2Quad and earlier, computers are starting to have issues 
> with the latest openSuse and I am looking to going all macOS. Or, close to 
> all. My brother-in-law handed his old MacBook Pro CoreDuo done to me and I 
> have found use for it as it runs software I have for my PowerMac G5. Was able 
> to pickup aMid-2012 MacBook Pro i7 for a song and am wondering if anyone has 
> had luck with DLPlus or mComm on macOS? 
> 
> I have 10.6.8 Snoiw Leopard on the CoreDuo and 10.15.7 Catalina on the i7.
> 
> God Bless,
> 
> GregS <><

Re: [M100] DLPlus or mComm for macOS 10.15.x

[Joshua O'Keefe]

On Oct 14, 2020, at 8:27 AM, Greg Swallow  wrote:
> .Was able to pickup aMid-2012 MacBook Pro i7 for a song and am wondering if 
> anyone has had luck with DLPlus or mComm on macOS? 

Greg,

The mid-2012s are great machines -- my daily driver is the 12" of that vintage 
with memory and disk upgrades. I have not yet tried to bring up 
dlplus/mComm/LaddieAlpha since I mostly connect to my storage server, but I'll 
give it a try and report back to the list.  I don't foresee any potential 
issues with dlplus (although It doesn't support DME directory browsing, so I 
mostly do not use it these days), and I've been wanting an excuse to try mComm.

LaddieAlpha ought to run (I have no issues with it in a Linux container) but 
the non-native runtime requirements could be painful to get set up on macOS.

[M100] DLPlus or mComm for macOS 10.15.x

[Greg Swallow]

All,

Most of my old, Core2Quad and earlier, computers are starting to have issues 
with the latest openSuse and I am looking to going all macOS. Or, close to all. 
My brother-in-law handed his old MacBook Pro CoreDuo done to me and I have 
found use for it as it runs software I have for my PowerMac G5. Was able to 
pickup aMid-2012 MacBook Pro i7 for a song and am wondering if anyone has had 
luck with DLPlus or mComm on macOS? 

I have 10.6.8 Snoiw Leopard on the CoreDuo and 10.15.7 Catalina on the i7.

God Bless,

GregS <><

Re: [M100] SPAM-LOW: Model 100 Boot Issue?

[Jeffrey Birt]

I started a video series a while back about the general troubleshooting steps 
for vintage computers. The first episode covers all the basic evaluation steps 
like checking for voltages, reset circuit, clock, bus activity etc. These steps 
will quite often give one enough information to locate the general source of 
the problem, i.e. no clock check the crystal and clock generation circuitry.

 

https://youtu.be/INtUSx0q9ME

 

Jeff Birt

 

From: M100  On Behalf Of Charles Hudson
Sent: Wednesday, October 14, 2020 9:14 AM
To: m100@lists.bitchin100.com
Subject: SPAM-LOW: [M100] Model 100 Boot Issue?

 

I do have a scope and will check for crystal output.  Thanks for the suggestion.

 

-CH-

 


 

 

Virus-free.  

 www.avg.com 

 

[M100] Model 100 Boot Issue?

[Charles Hudson]

I do have a scope and will check for crystal output.  Thanks for the
suggestion.

-CH-


Virus-free.
www.avg.com

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

Re: [M100] Model 100 boot issue?

[Josh Malone]

On Tue, Oct 13, 2020 at 6:50 PM Charles Hudson  wrote:
>
>   and then checked the PSU voltage and replaced the AAs as first steps.

There are multiple voltages from the PSU; were they all okay? (+5Vdd,
-5Vee, +3 to +5 Vb)

> after reassembly I inserted a fresh set of batteries.  I must have left the 
> power switch "on" because
> when I turned it right side up I saw some characters on the display.

This indicates to me that the memory power switch had been left in the
ON position as well. This likely drained your memory NiCad beyond a
safe point. It will need at least 24 hours to attempt to recharge.
Again,the Vb (battery power rail) is critical here as this is what
actually powers the RAM chips. No RAM == unhappy computer.

You also mentioned re-seating the display cable. Does the connector
look physically okay? The proximity to the AA compartment often leads
battery corrosion to affect this cable. If this machine has *ever* had
any battery leaks, this cable is suspect, along with most of the power
supply circuit.

Download the service manual from
https://archive.org/details/TandyM100ServiceManual and follow the
troubleshooting guides in the back, keeping in mind the age of these
parts :)

Good luck!

-Josh