Macintosh 512K
This computer belongs to a customer, the request was to check the overall machine and specifically low brightness / contrast and service the floppy drive.
Work done
- Inspect boards
- Test capacitors and replaced faulty
- Serviced floppy drive
Inspection
Analog board:
There were 2 RIFA paper capacitors on the board, these tend to go bad and explode, so I replaced them with modern equivalents:
Aside from 2 Rifa capacitors, the blue axial capacitor tested bad, it looks out of place and was probably replaced at some point. All other capacitors tested good.
When I first powered on the computer, the brightness was very low and the knob on the front couldn't adjust it high enough. I checked a few common resistors, but all tested correct.
After replacing the bad capacitor and adjusting the pots, the brightness was normal again.
Floppy drive
The floppy drive was a bit dirty and all the lubricant had dried up:
The ejection mechanism was still in good shape:
Fully disassembled:
All cleaned up and ready to go back together: