General Category > Lisa Troubleshooting and Repair
Help please for my Lisa 2/5
pintoguy:
Thanks. One repair that I used for some very badly damaged pads was to hammer down a thin copper wire on an anvil, until it became a thin strip. I them soldered that strip to the old pad. Not the cleanest way to proceed, but it did work OK, with minimal thickness increase.
And yes, I communicated with John (vintagemicros) but he does not have 2/5 IO bare boards in stock. I might go the AlexTheCat123 github route, just like I did with the MB
sigma7:
--- Quote from: pintoguy on August 11, 2023, 07:27:42 pm ---I communicated with John (vintagemicros) but he does not have 2/5 IO bare boards in stock.
--- End quote ---
Perhaps that was a miscommunication or a while ago... moments ago John confirmed that he does have some in stock now (unless I misunderstood).
pintoguy:
--- Quote --- Perhaps that was a miscommunication or a while ago... moments ago John confirmed that he does have some in stock now (unless I misunderstood).
--- End quote ---
This was 2 weeks ago. Perhaps he understood I wanted to finished board. I'll ping him again. Thanks
sigma7:
--- Quote from: blusnowkitty on August 07, 2023, 04:57:46 pm ---The ROM can be reburned or replaced easily, it's a standard 27(C)16. ROM images are up on Bitsavers.
--- End quote ---
There are also the relatively recent 400k/800k "universal" variants in the files section: Lisa I/O Board ROMs
IIRC, the I/O Board EPROMs are 2732; the expansion boards' are 2716 (there are a couple of exceptions).
pintoguy:
This week's update: Looks like the EPROM is OK. It reads and verifies the 341-0290-B BIN file perfectly. So I think we can put this to bed.
I noticed that +5B only reads 4.8V or so, when +VSTBY is 5.5V. On my "good" board, it's 5.3V. So I suspected that diode D9 was therefore bad, but after I changed it, I still have the problem.
But..., chip 8T97 at U1F is very hot to the touch, when it's perfectly cool on my good board. I had told Alex that it was an LS367, but I was wrong, as I simply read what's written on PCB. I'll trace the signal around that and see what happens, but I hope I have found the culprit.
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