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Old 24th Jul 2021, 2:42 am   #71
Uncle Bulgaria
Nonode
 
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Join Date: May 2016
Location: Cornwall, UK.
Posts: 2,315
Default Re: Uher CR 210 Cassette Recorder Check Out

Aha! You've found it. I haven't got the user manual, only the service one. That looks like the reason there's a signal on Access pin 6 - film dubbing! Bizarre proof-reading...

Here's the back of my board 700 showing the diodes. I put the front up a few posts back so you can see if it matches yours, with the large tantalum where the diodes are marked on the later circuit diagram.

I suppose your D12 would have shown up as an error on auto-reverse.

I've fixed the shorting. It was a trying road, but logic got me there in the end. C28 goes from +9.5V to ground. In between the two PCB pads is a larger copper area for the attachment of the link wire to pin 905. After much gnashing of teeth, I worked out that there's a hole beneath that pad, and the copper lining of that hole is very, very close to the ground pin of C28 on the top side of the PCB.

On a bit of pressure being applied and flexing the PCB, the positive side of C28 brushed the ground plane and R67 was shorted. I've pulled off the C28 pad for the wire, and cleaned out the hole of copper. The 905 wire now goes directly to C28+ on the PCB hole.

All that remains is to manufacture new latching mechanisms for the loudspeaker, ALC and internal microphone switches, make a new loudspeaker switch, and follow the service procedures...
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