68kMLA Classic Interface

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Mac Classic II Dump Rescue - Help Needed
Posted by: Iamthedavel on 2018-11-13 19:36:04 I rescued a Mac Classic II from the dump several years ago and just decided to try to bring it back to life. Upon powering it up the first time I received a garbled pattern on the screen, after doing some research lead me to removing the logic board and cleaning it with isopropyl alcohol and reseating all the chips that I could. The capacitors did not show the visible leakage that I have seen pictures of and after the removal of a layer of dust the board looks very clean. The PRAM battery is dead but not leaking so I have just removed it entirely to make sure that does not cause any issues. After reassembling the unit I got a chime on boot up and the display now shows a picture of a disk with a ? flashing in the center, all looked good but it suddenly starting emitting a loud whining noise that grew in volume and pitch to the point I was afraid something was about to blow up. However after a few minutes the noise drops to a low pitch but with a constant ticking noise. I then tried to see if it was an issue with the SCSI drive which appears to be faulty but unplugging this drive has no affect on the whining noise. I have determined that it is indeed only coming from the speakers as plugging in earphones moves the sound to the earphones. I tried for several hours to look up possible causes and remedies but found very little except for a post by someone who had the same problem and had his logic board recapped but still had the whine, the posts to his problem referred him to this board... Does anyone have any suggestions on what I should be looking at doing to remedy this issue?
Posted by: bibilit on 2018-11-13 23:24:33 Remove and replace capacitors on the Logic Board first, but also the ones on the Analog Board (plenty posts on this subject)
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