Hello : )
Glad to be a new member of this community! I hope that someone can help me a bit : )
I recovered a Macintosh Plus, almost completely dead. Battery leaked on the analog board but no big damages on the traces or other components.. still. Once plugged in and turn on the only thing that happen is a repetitive "ticking" or chirping sound. The area is definitely around the T3 transformer, but cannot pinpoint exactly the location. Here's some data
INTERNATIONAL BOARD 240v
What I have done so far.
- reflow all the cracked solder joints and beyond
- replaced the C33 and C36 rifa caps.
- made sure that R55 is still good, reading 33k o as per colour coding.
- tested diodes, some allowed current both ways, but when out of the board were perfectly fine
Got some cigarette marks on the vinyl cover in proximity of R 52 (the big cemented resistor below T3) but again, tested just fine at 1Ko.
Video of the clicking attached, note that when close to the main transformer volume goes higher.
Once On voltages reading from the floppy connector are very weak and oscillating randomly between 0.5 and 1 V on both the 5 and 12V lines..
I will investigate further but any help will be much appreciated.
Thanks!
Glad to be a new member of this community! I hope that someone can help me a bit : )
I recovered a Macintosh Plus, almost completely dead. Battery leaked on the analog board but no big damages on the traces or other components.. still. Once plugged in and turn on the only thing that happen is a repetitive "ticking" or chirping sound. The area is definitely around the T3 transformer, but cannot pinpoint exactly the location. Here's some data
INTERNATIONAL BOARD 240v
What I have done so far.
- reflow all the cracked solder joints and beyond
- replaced the C33 and C36 rifa caps.
- made sure that R55 is still good, reading 33k o as per colour coding.
- tested diodes, some allowed current both ways, but when out of the board were perfectly fine
Got some cigarette marks on the vinyl cover in proximity of R 52 (the big cemented resistor below T3) but again, tested just fine at 1Ko.
Video of the clicking attached, note that when close to the main transformer volume goes higher.
Once On voltages reading from the floppy connector are very weak and oscillating randomly between 0.5 and 1 V on both the 5 and 12V lines..
I will investigate further but any help will be much appreciated.
Thanks!
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