Hello everyone.
I acquired a Macintosh Plus, to try to repair it. After the initial disassembly I found out the battery had leaked and damaged the analog board. It has an International version, but set for 120 V. The thermistor at R36 was split in half, so after cleaning what I could with isopropyl alcohol I replaced the thermistor, the capacitors C33 and C36 (those were the Rifa capacitors and were broken, too) and C24, that was bulged. It initially turned on, though no startup bong, and the image was too wide and tall. The next day, it was making the flupping noise from the Pina books. I had some other capacitors, so I replaced C27, C28 and C30, and also took Q8 to test it out of the board, and was measuring the 50 Ohm stated in one of the books, too. Also, the rectifiers are measuring what's stated there.
Yesterday, by mere chance, a cousin mentioned he found a 512k that was powering on, so I tested the logic board with that analog board and it played the startup bong and then correctly displayed the floppy icon.
I am now wondering if it is feasible to identify and repair my own analog board. I attach some pictures, maybe you're experience will allow you to see a glaring issue that I failed to note.
The white pads are 3M velcros, I tried to place them where there were no soldered pins.
Thanks in advance.
View attachment DSC_0127.JPG
View attachment DSC_0126.JPG
View attachment DSC_0124.JPG
I acquired a Macintosh Plus, to try to repair it. After the initial disassembly I found out the battery had leaked and damaged the analog board. It has an International version, but set for 120 V. The thermistor at R36 was split in half, so after cleaning what I could with isopropyl alcohol I replaced the thermistor, the capacitors C33 and C36 (those were the Rifa capacitors and were broken, too) and C24, that was bulged. It initially turned on, though no startup bong, and the image was too wide and tall. The next day, it was making the flupping noise from the Pina books. I had some other capacitors, so I replaced C27, C28 and C30, and also took Q8 to test it out of the board, and was measuring the 50 Ohm stated in one of the books, too. Also, the rectifiers are measuring what's stated there.
Yesterday, by mere chance, a cousin mentioned he found a 512k that was powering on, so I tested the logic board with that analog board and it played the startup bong and then correctly displayed the floppy icon.
I am now wondering if it is feasible to identify and repair my own analog board. I attach some pictures, maybe you're experience will allow you to see a glaring issue that I failed to note.
The white pads are 3M velcros, I tried to place them where there were no soldered pins.
Thanks in advance.
View attachment DSC_0127.JPG
View attachment DSC_0126.JPG
View attachment DSC_0124.JPG
