Back to the LC III.
Last we left off I had been removing the rust on the power supply, inner shields, etc.. the PSU has been recapped and it's working. Tested it on another board. Went from this:
to this and functional:
As for the logic board, went from this:
to this:
Could not salvage the old memory chips. The ones above were taken from another SIMM module I had. Same part #. All the bodge wires were necessary to resolve pads that were gone from the battery juice.
Also replaced all the caps, removed the sound chip (U1) and also U22 as there was a lot of corrosion. Cleaned under the chips and put them back on. Reflowed solder joints on U8 and U16. Removed and cleaned under the VRAM socket and the memory socket. Cleaned out the area around the old battery, checked traces, and replaced with a coin cell holder. ROM modules were tested on another board and found to be fine. Used deoxit on the sockets and reseated the ROM modules.
Finally got the board to chime. But it's not perfect. Chimes about 9 of 10 times right now... when it doesn't work, it just sits there with no chime. Need to look into this some more later.
But the main problem right now is NO video. Checked the signals and I'm not getting Red, Green, or Blue coming through at all. I'm seeing no disk activity also so it looks like it's getting stuck post good chime (no bad chime or anything).