68kMLA Classic Interface
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| SE/30 burnt ROM socket | |
| Posted by: MacinPosh on 2019-03-16 10:25:30 I was in the process of cleaning and recapping an SE/30 logic board which had been subjected to a battery leakage. I've checked and rerouted all the rotted traces (totalling about 15) between the RAM, ROM, VROM and GLU but when I was satisfied enough to attempt a boot, pin 63 on the ROM burnt out (causing pin 64 to fall off, but pin 63 was definitely the offender) leaving me with a dead SE/30. Any ideas what might have caused the sudden burning on the ROM? I've checked it in another machine and now it only boots a grey screen with death chimes. Maybe there is a short I haven't noticed, or there are broken internal traces too? Any suggestions are much appreciated, but I fear this machine is un-repairable.   | |
| Posted by: olePigeon on 2019-03-20 13:11:19 My guess would be a short with some sort of power trace. I'm not knowledgable enough to give any constructive technical help, though. | |
| Posted by: dochilli on 2019-03-21 05:58:20 Here you can see the pinout: Pin 63 is +5V. Seems to be a short. | |
| Posted by: trag on 2019-03-21 16:54:46 To elaborate a little, pin 63 is 5V, pin 64 is GND. So a short between those two would be bad and burn things as observed. Did you try the damaged ROM in another machine, or the repaired logic board in another machine? If the ROM, I would get out a continuity meter and check that all four (?) ROM chips on the module have good connection to the other ground pins besides 64. It seems unlikely, but perhaps 64 was connected to something in isolation and now it isn't present, so no worky. | |
| Posted by: MacinPosh on 2019-03-21 23:22:40 I haven't found any shorts around the ROM pins, and the same issue happened to two different ROM chips, so I don't think the ROM is the issue. As I mentioned in my previous post, the ROM now only boots to death chimes and B&W Stripes in my other working machine | |
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