Hi,
I have recently acquired a Macintosh Classic, my first Apple device ever. Which means I have zero experience.
When turned on, the machine shows a checkerboard pattern, likely indicating that it wants its logic board capacitors replaced. There was no battery leakage yet (although the Lithium battery measured at negative 0.5V), but small signs of corrosion around the electrolytics on the logic board (plus a fair amount of dust). I have cleaned the board with ethanol ("rödsprit"), removed the leaky electrolytics and replaced them with tantalum capacitors which seems to be the correct approach.
Unfortunately, the machine only produces a little noise on the speaker when turned on and only shows a checkerboard pattern (some pixels are flickering). I did some poking around with a multimeter on the logic board, but did not find any broken traces. The corrosion was also very minor and cleaned up nicely. To my eyes, the board looks fine - but does not work. I haven't done any live tests because the cables are very short and I did not feel particularly brave near a running CRT yet.
I have not removed or looked at the analog board yet. The voltages on the hard drive power connector measure fine (4.9V and 11.9V) and since the screen shows an image, it should be fine for now. According to some information I found, it should also need a recap, but that can wait until the system works... right?
In any case, I don't really know where to start troubleshooting these systems, so I've attached pictures of the board (scanned at 300 dpi) in the hope that you see something that I don't.
Best Regards,
Svenska
I have recently acquired a Macintosh Classic, my first Apple device ever. Which means I have zero experience.
When turned on, the machine shows a checkerboard pattern, likely indicating that it wants its logic board capacitors replaced. There was no battery leakage yet (although the Lithium battery measured at negative 0.5V), but small signs of corrosion around the electrolytics on the logic board (plus a fair amount of dust). I have cleaned the board with ethanol ("rödsprit"), removed the leaky electrolytics and replaced them with tantalum capacitors which seems to be the correct approach.
Unfortunately, the machine only produces a little noise on the speaker when turned on and only shows a checkerboard pattern (some pixels are flickering). I did some poking around with a multimeter on the logic board, but did not find any broken traces. The corrosion was also very minor and cleaned up nicely. To my eyes, the board looks fine - but does not work. I haven't done any live tests because the cables are very short and I did not feel particularly brave near a running CRT yet.
I have not removed or looked at the analog board yet. The voltages on the hard drive power connector measure fine (4.9V and 11.9V) and since the screen shows an image, it should be fine for now. According to some information I found, it should also need a recap, but that can wait until the system works... right?
In any case, I don't really know where to start troubleshooting these systems, so I've attached pictures of the board (scanned at 300 dpi) in the hope that you see something that I don't.
Best Regards,
Svenska