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Yes, the focus dot keeps going back and forth at 35rpm. Something like 3-4 times a sec. At 45rpm it seems more stable.
I found some time to strip some more parts today. I was not in the mood to test things. I just did some mindless desoldering (BTW I love my desoldering gun :) )
Here is a shot of the pcb now.
Attachment 19213
The regulators at the back are not used anymore. Just the one on the left. I need to do something about those big caps too...
Trying to nail what could be causing your oscillation issue. Frustrated by not having enough info on the inards of the 6680
What you have done should have worked
Hope you find the gremlin soon- I want to mod one of my deck to "bare bones" mode
Hopefully it won' t be the FG ransistor that was fried...
I have a second unmodified pcb I could use as a donor, but I would like to keep it functional.
Perhaps a nice opportunity to find alternative transistors to avoid paying any more silly money. Perhaps bc550 or something with lower noise
If the dots move, the strobe is stable so you can rule out the x-tal and the logic part of the 6680. My guess remains it is some component in one of the filterpath. I see you swapped some of the caps. Are they all fixed?
Yes, everything is soldered. My first candidates are a few caps that are rated at 25V. Although all of them are ok visually.
No accidentally cut traces?
Just for interest - when I recapped my SL-1200Mk2 I checked all removed capacitors and everyone has passport capacity with tolerance +5..-10% and suitable ESR (I compared ESR with new ones). However, caps should be revised first of all anyway.
Yes I did almost the same when recaping mine. The tt was working flawlessly until I moronically overvoltaged almost everything
The only trace that I cut was the supply of 6682, because I used an external reg for it. This should be rather irrelevant now?Quote:
Originally Posted by Co&
What do you have in mind? Perhaps I lifted a pad and did not notice.
Exactly!Quote:
Originally Posted by dimkasta