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Zenith Z-100 boot ROM image wanted

>Thanks, fingers crossed that the RAM upgrade helps!

Yea, cross all fingers AND toes :p I'm real skeptical that more ram is going to solve it.
I think your physical ROM chip is incompatible somehow, but ram is cheap and will be nice to have it filled.
If more ram doesn't fix it, be sure and put old ROM back in and test the new ram configuration with the diagnostic disk to be sure you didn't add another problem.

Larry G
 
Hi,

I fitted the additional video RAM, enabled RGB on the jumpers, and as Larry expected still no luck with the v2.5 monitor ROM.

I plugged the original v1.2 ROM back in, and ran the disk based diagnostics (nb video now OK, had to switch the external monitor to 75 ohm termination - doh!). I had to run the diagnostic configuration to allow for 3 banks of 64K video RAM, and also for some reason had to change the main memory from 2 banks (128K) to 3 (192K). Previously I the system memory diagnostics failed due to insufficient memory, I see now this was a misconfigured. All the memory tests passed (yeah!), but I have a problem with the serial port loop-back test.

This was the reason for investigating the ROM in the first place, as I have not been able to get either CP/M ZIMP or Kermit to work, so now the memory is all good I have a way forward.

Shame I couldn't get the newer ROM to work, one for another day maybe.

Thanks for the help. if Roman needs assistance with his power supply please start a new thread.

Regards,
John
 
I just ran the disk based diagnostics for the serial port and with a plain 25 pin extension cable from J1 to J2 it passes all the external and remote loopback tests, synchronous and asynchronous.
The manual indicated a special cable was needed for synchronous tests but evidently not ...

BTW - I would be more than happy to help Roman troubleshoot his power supply if there is a schematic.

Larry G
 
1980s_john said:
I fitted the additional video RAM, enabled RGB on the jumpers, and as Larry expected still no luck with the v2.5 monitor ROM.
Click to expand...

Update on my searches for info on this found the following on comp.sys.zenith.z100 from 1987, looks like I have a way forward with the upgrade to the V2.5 ROM :)

====================
boot ROM version question

I have an "old" motherboard with version 1.2 boot ROM, and would
like to upgrade to a newer boot ROM version. What is the highest
boot ROM version (& part #?) that will work with the old motherboard,
and how should J101/J102 be set?
I bought a 2.x ROM from Heath over a year ago, but my system
would not boot with it (trying every combination of J101/J102),
so I sent it back for a refund. As I remember, the system would
beep once and that was it. Since I had S101 set for auto boot,
I don't know if it would have gotten as far as the "hand prompt"
or not.

Thanks in advance for any information.

----------------
To Upgrade Boot Monitor V1.X to V2.x (2.9 is latest) requires changing
EPROMs, moving J102, and changing/torturing a PAL chip. The exact
details will be forthcoming in a week or so in the ZUpGrade Series.
This should give me enough time to refind the info...
Cheers,
Gern

Zupgrade part 4 is here: https://groups.google.com/forum/#!s...comp.sys.zenith.z100/1OirJiaerZg/rPUx6lsXImUJ

Key part for updating from the V1.2 ROM is:

Upgrade From Version 1.x:

If the current MTR-100 version is 1.x then 3 changes must be made:

1) The ROM Address Selector PAL IC at U161 (part number 444-129) must
either be replaced with a ROM Address Top 32K Selector PAL IC (part number
444-129-1, about $7.00) or the 444-129 PAL IC must be 'converted' to
perform the new function.

The 444-129 IC can be converted into the function of a 444-129-1 IC by
connecting input pins 2 & 3 high to Vcc at pin 20.

a) Remove the IC from the socket and bend up pins 2 & 3.

b) Bend pins 2 & 3 together and solder them both to a small wire one inch
long.

c) Carefully solder the other end of the small wire to the top of pin 20.
Do not bend pin 20 or impede the pin from normal insertion into the socket.

d) Insert the converted IC into the socket. Pins 2 & 3 must remain above
the socket, but pin 20 must go into the socket normally.

2) Move Jumper J102. This allows the use of a 16K ROM.

3) Replace the ROM at U190 with Heath part number 444-276-1 MTR-100 Version
2.9 [*]. Upgrade completed.
 
I've finally got a working V2.5 monitor ROM! Thanks to Roman for the ROM dump and Gern from comp.sys.zenith.z100 for the instructions which worked fine, and Larry for running so many checks on his machine. I did the mod on the PAL to make it work like a 444-129-1 (which everyone except me seems to have I fitted!), the self test and color bar etc. all look good, and I can finally boot from 360K floppies (an option not supported on ROM V1.2).

Hope the next guy gets there more quickly than I did :)

Thanks again for everyone's help,
John
 
Bumping this old thread, to say thank you! I also successfully upgraded my Z120's 1.2 boot rom to 2.5 following the above instructions.

Two more questions: 1) does anyone know where to find the latest (?) 2.9 boot rom? and 2) what is the difference between 2.5 and 2.9?

-Dave
 
So I think the 2.9 ROM is the last official ROM, but Steven Vagts (Z-100 Lifeline) offers a v4.3 MTR-ROM that has better PC compatibility and support for newer hardware. Not sure what the differences are between 2.5 and 2.9.
 
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