Well, I had some work I needed to do tonight, and I was so desperate to avoid doing it that I cracked open the 128 and started poking around.
Opened it up to discover a dusty, nasty situation inside - there was quite a bit of dust and debris inside the case. There was even what looked like a bit of a leaf or pine needle lodged into a corner of the CRT, that can't be good. It must have been stored in a dirty garage for some time.
(look for the leaf at the bottom of this picture!)
Pulled out the logic board to discover a similar situation. The board was very dusty with a fine whitish dust. But it was clear that this board has not been upgraded to 512k, it has soldered MT4264 chips. ROMs are in the right way but may need reseating. With so much dust it seems like a short could be possible.
Next step: Opened up a known working Mac Plus, and pulled out the logic board. Connected it to the 128's analog board, fired it up, and...
Success! Started right up, booted from a floppy (external, the internal drive is still gunked up).
So it looks like the analog board in the 128 is ok. That being eliminated, seems like the first obvious step is to clean the board off, it certainly needs it. Byrd mentioned meth spirits - might look into that. I've also used isopropyl alcohol when cleaning circuit boards with some success. Perhaps this is the same as meth spirits and I've forgotten my high school chemistry..
In addition to the condition of the board, I did notice one odd thing on the logic board. There was what looked like a resistor array connected to some of the pins on the IC at D-15 -
It was connected to 4 of the pins of the chip (8432, SYP6522) and one of the leads of the component (capacitor?) at C30. Some of the pins of the resistor array were clipped off and not connected. This may be normal, but it stood out as a bit odd.. Is this a normal component on a 128 logic board?
Reading through the Macintosh R&U Secrets book again, I saw a possible clue in an unexpected section of the book. Under Lisa/Mac XL repairs, figure 13-14 shows a screen pattern that looks very much like what I had - thick vertical bars. From the book, "This pattern indicates total RAM failure. On the Lisa, Mac XL, Mac Plus, and Mac SE it generally means the cards and/or SIMMs are missing. On the 128K to 512Ke with certain memory upgrades, it generally indicates a problem with the 68000 chip." Well, it didn't look like there were any memory upgrades on this board, but it's a curious similarity. Perhaps if many of the RAM chips are bad, it can't even muster the Sad Mac error code.. I suppose CPU error is possible too.
I think next steps for this are a good cleaning, reseat the socketed ROMs, and try again. I'm hoping for at least a sad mac code. If anyone has any ideas based on the new information, or if you think of anything I should look for, please let me know, thanks!
Opened it up to discover a dusty, nasty situation inside - there was quite a bit of dust and debris inside the case. There was even what looked like a bit of a leaf or pine needle lodged into a corner of the CRT, that can't be good. It must have been stored in a dirty garage for some time.
(look for the leaf at the bottom of this picture!)
Pulled out the logic board to discover a similar situation. The board was very dusty with a fine whitish dust. But it was clear that this board has not been upgraded to 512k, it has soldered MT4264 chips. ROMs are in the right way but may need reseating. With so much dust it seems like a short could be possible.
Next step: Opened up a known working Mac Plus, and pulled out the logic board. Connected it to the 128's analog board, fired it up, and...
Success! Started right up, booted from a floppy (external, the internal drive is still gunked up).
So it looks like the analog board in the 128 is ok. That being eliminated, seems like the first obvious step is to clean the board off, it certainly needs it. Byrd mentioned meth spirits - might look into that. I've also used isopropyl alcohol when cleaning circuit boards with some success. Perhaps this is the same as meth spirits and I've forgotten my high school chemistry..
In addition to the condition of the board, I did notice one odd thing on the logic board. There was what looked like a resistor array connected to some of the pins on the IC at D-15 -
It was connected to 4 of the pins of the chip (8432, SYP6522) and one of the leads of the component (capacitor?) at C30. Some of the pins of the resistor array were clipped off and not connected. This may be normal, but it stood out as a bit odd.. Is this a normal component on a 128 logic board?
Reading through the Macintosh R&U Secrets book again, I saw a possible clue in an unexpected section of the book. Under Lisa/Mac XL repairs, figure 13-14 shows a screen pattern that looks very much like what I had - thick vertical bars. From the book, "This pattern indicates total RAM failure. On the Lisa, Mac XL, Mac Plus, and Mac SE it generally means the cards and/or SIMMs are missing. On the 128K to 512Ke with certain memory upgrades, it generally indicates a problem with the 68000 chip." Well, it didn't look like there were any memory upgrades on this board, but it's a curious similarity. Perhaps if many of the RAM chips are bad, it can't even muster the Sad Mac error code.. I suppose CPU error is possible too.
I think next steps for this are a good cleaning, reseat the socketed ROMs, and try again. I'm hoping for at least a sad mac code. If anyone has any ideas based on the new information, or if you think of anything I should look for, please let me know, thanks!