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Post by Mike Kunzelman on Jul 14, 2022 23:41:02 GMT
![]() I have a 464 that is blowing the 3A fuses inside the power supply. Got the machine used, been working through slowly, thought I was making progress. Had it scanning and putting a selection on the turntable and dropping the arm on it to play. At some point it stopped scanning and the basket won't run any more. Found blown fuses in the power supply. Tried the one-time replace and blows immediately. Got out the schematic and see it goes to a rectifier, so pulled that board to check it. The circled diodes in the photo are checking as a short in diode check. I just want to verify that is not correct and i'm on some kind of path here. (the 100 micro-farad cap on that board has made it's insides on the outside, i think that's all the oily residue.) Thanks for anyone that can help,  |
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Post by jukenorman on Jul 15, 2022 8:18:20 GMT
Hi Mike,
Yes if the diodes are showing short circuit, it is certainly a problem! It looks like what you have there are two full wave recifiers that look like a single full wave recifier at first glance (notice the centre tap on the transformer). You have to bear in mind that there is very likely a good reason why these diodes have popped - I would recommend that you power it up via a dim bulb tester when you come to power it up again.
Norman.
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