68kMLA Classic Interface

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128k 630-0101 board blowing fuse on analog board
Posted by: Joopmac on 2024-09-05 12:24:34
hi there =)

i have a nice 128k board, but this one blows the fuse on the analog board.

already replaced is TSM IC, Q1, capacitors on the logic board, checked the ports for shorts...


any hints where to look, is there a common point of failure on these?

greetings!
Posted by: bibilit on 2024-09-06 11:55:41
Hi, can you have a look at the four diodes (CR22 to CR25) on the right of the board ?

Those are serving the purpose of diode bridge / rectifier.

If one of them is shorted, the fuse will blow.
Posted by: Joopmac on 2024-09-06 13:45:04
Sorry, i was not clear but its the logic board that causes the fuse to pop on the analog board
Other Logic boards go juuust fine 🙂
I have recapped and fresh analog boards and they work great

Thanks!!
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