68kMLA Classic Interface

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Classic II Analog Board / no output

Posted by: bibilit on 2016-05-03 07:17:21 I am trying to fix a Classic II Analog Board, the primary side is ok and the fuse also, but i have no output on the secondary side (0 volt) Removing and replacing capacitors didn't solve anything, probably a faulty component, but don't know where to look next.

Posted by: bibilit on 2016-05-14 07:52:06 Not fixed this unit yet, but had another one to repair, blowing fuses all the time. My first bet was that the bridge rectifier was bad, and at first check - and + where shorted, but on removal all was ok. Turned my attention to surrounding components, in the end The Mosfet on QP2 was shorted (IRFBC40).... a swap, some new caps on the Logic and Analog board and i have a nice working unit Already been talked about here, so this Mosfet has a tendency to go bad.

Posted by: uniserver on 2016-05-15 11:55:42 yea seems like the 230v ones.... including the Color Classic's,  they get hard parts that go out.

Posted by: bibilit on 2016-05-15 22:57:25 Thanks Uni. Any idea why the first is no delivering any output ?

Posted by: uniserver on 2016-05-16 00:06:39 the opto oscillators go on those 230v AB's. might be something to look at.

Posted by: bibilit on 2016-05-16 09:03:47 Ok thanks is this the CNY17G-3 ? For my information, is this component acting as a switch ? Also, do you know the difference between the CNY17-3 and the G variant ? (as the first can be found easily) Thanks again.

Posted by: bibilit on 2016-06-16 01:08:01 No luck here. I saved one board yesterday, but replacing the Optocoupler in the others didn't solved the issue. Any idea where to look next ?

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