Amiga 1000, Kickstart, DiagROM

[Cheshire Noir]

Hey all,
I've got my long suffering Amiga 1000 on the bench right now, trying to diagnose what ails it.
First up Symptoms:
It boots up to the Kickstart screen, you insert the Kickstart disk, hit happily chugs along to the reboot stage (Where, from 30 year old memories, it would ask for the Workbench) and then I get a black screen, then it loses video sync and that's all that she wrote.
https://www.youtube.com/shorts/d-g39om62zw <- video of the boot sequence.

What I have tried:
Well, first up I tried a different Kickstart disk. No change. I also tried using a Gotek in case the drive itself was bad. No change.
I've also removed, socketed and tested the RAM on the mainboard. All OK. (The logic here was if WB was being loaded successfully into the Mezzanine board, to the reboot point, It was probably RAM elsewhere causing the problem.)

I have got a set of Chucky's excellent DiagROM images for Amiga 1000, and it starts up OK, dumping to the serial port. It doesn't get very far. It stops with the last line of - Parallel Code $fd - Start of chipmemdetection
(I tried it without the front RAM 256K expansion, just to eliminate that and it stops on the same location...

IMG20230316112313.jpg

Not really sure where to go next...
All suggestions welcomed. As for local tools, I have: an oscilloscope, multimeter (Voltages check OK), logic probe, TL866ii+ and access to a retro chip tester pro.

John "Cheshire Noir" Parker.

[amimjf]

Hi,

Never used Diagrom on an A1000 ,(just 500s and 2000s), but there is a newer version 1.2.1, in which the release notes say memory detection has changed.

[Cheshire Noir]

Unfortunately it appears that the A1000 DiagROM is stuck at 1.1

John "Cheshire Noir" Parker.

[stephen_usher]

I would not trust the Kickstart RAM until that has been tested. Even a one bit error in one RAM chip could potentially cause the ROM images to crash in unexpected ways. Assume nothing. :-)

[Cheshire Noir]

Thanks @stephen_usher.
Working along that path right now. Man it was a pain to remove the RAM. I'll report back once I have new sockets and all "known good" ram in place.

john "Cheshirenoir" Parker

[Cheshire Noir]

Unfortunately, when I tested all the RAM from the A1000 in the Retro Chip Tester, it comes back fine. I'll need to dig deeper.

John