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Leaky caps in Quadra 840AV CD-ROM drive
Posted by: mitchW on 2014-10-26 08:27:10 I recently acquired a working, but neglected Quadra 840AV. It came with 3 hard drives installed, an original CD-ROM drive, and with a 64 MB of RAM. It clearly needed a total recap of a motherboard and a good cleanup, which I did. Then I tested the machine, and I found out that a CD-ROM drive wasn't detected, even that it was connected properly. I figured out that it must be the drive that failed. Then I cracked open the Sony CDU561-25 drive, and to my surprise, I found capacitors that have leaked and corroded the PCB. The damage was quite bad, but fixable. There was a group that leaked, and they were three 16V 47uF and two 16V 10uF silver electrolytic SMDs. On the left side of the PCB, there were four 6.3V 100uF that looked okay, but when I changed them, they were certainly on their way to fail (fishy smell). So when I replaced them all with tantalums, the CD-ROM drive now works flawlessly, and I know that they won't leak ever again. Also, I was impressed with the build quality of this particular drive, it is massive and it has a voice coil laser mechanism, which just screams high quality all around. So, next time your CD-ROM drive fails, check the caps inside the unit. Also, if you have a Sony CDU561-25 or similar, it will be the smart idea to change the caps just to be sure, even if they are not leaking. Sometimes the CD-ROM unit will cost alone more than a complete computer, so it is worth it.
Posted by: CelGen on 2014-10-29 16:34:51 Oh yeah, these. I had the same problem in an IBM rebranded drive. It wouldn't read discs at all. I don't even question these caps anymore. They are replaced on sight if they are more than 10 years old. Also, I was impressed with the build quality of this particular drive, it is massive and it has a voice coil laser mechanism, which just screams high quality all around. That was all they had in the early days. It wasn't until the late 80's at the soonest that we started to see mechanical servo mechanisms.
Posted by: uniserver on 2014-10-29 23:22:04 Good tip! Yep I have recapped some of these for folks, I like much better when people send me just the boards instead of whole drive, just like those cannon mo optical drives in NeXT machines.
Posted by: trag on 2014-10-30 12:23:00 Oh. Good catch. I wish I had thought of/heard of this before I threw away all my old Yamaha 4260, 4416, etc CDRW drives. Maybe it wasn't the lasers. Maybe it was just failed caps. Argh.
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