Troubleshooting Amiga 1000 Chip RAM expansion
So I finally have gotten to be able to do some actual testing on my Amiga 1000 since I’ve gotten my mouse working, but I’ve found that the system does not work with the Chip RAM 256kb memory expansion, and progressively has gotten worse.
At first, it would load the Kickstart 1.3 ROM and the Amiga Test Kit 1.20 (slightly out of date but it’s what I’ve got), but the Kickstart Memory Test only detected the first 256kb of Chip RAM (which passes. Workbench also only detects 256kb). The Direct Memory Test did detect the full 512kb though, but threw some errors. Looked like 4 bits might’ve been having issues but I’m not very familiar with the program.
After that, the system just wouldn’t boot properly. Usually the screen would just go through its normal stuff then flash yellow then green (which I’m assuming is the CPU having a brief panic attack then realizing the RAM has something wrong with it). It did freak out and go turquoise at one point which was a fresh change of pace, then it just went back to yellow and sometimes green too.
Now it just stays Dark Grey before blinking light grey for a second, doesn’t get further. At least not within 20-30 seconds.
System still boots fine though when the expansion isn’t installed. Amiga Test loads and passes the memory checks, workbench loads fine.
I’ve cleaned the RAM expansion connectors with IPA, and have checked the traces and connections on the expansion board (they seem fine). Also I’m getting 5.1V on the 5V rail so that’s good.
I’ve also tried piggybacking two different 41464 RAM chips (in case one of them happened to also be bad) on each of the expansion RAM chips to no avail, though that might not be a definitive test.
My current plan is to desolder the Expansion Chip RAM chips one by one (to hopefully lower the amount of soldering/desoldering needed, starting with a couple guesstimated suspects) and testing them in my C64C or Tandy CoCo 3 to see if I can find any bad ones so the expansion unit is ruled out before I even try to investigate the Amiga itself.
Also unfortunately I do not have a keyboard currently. An adapter for one is currently in the mail.
Does anyone have any thoughts or advice though on what I should do or what would be a better means of diagnosing it? Thank you!