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Old 15th Sep 2020, 3:39 pm   #98
Uncle Bulgaria
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Join Date: May 2016
Location: Cornwall, UK.
Posts: 2,338
Default Re: Uher CR 240 AV Cassette Recorder

I have retained the capacitors I changed - mainly on the motherboard that were not decoupling properly - as I'd like to put them through the capacitor tester when I've built it to see if they are actually duff. I'm not a fan of the bodging 'recap' and, like you, want to know what's wrong!

I used Wurth Elektronik for the electrolytics as I thought aesthetically they were suitably Germanic, and it was a shame to remove the hard-cased distinctive Elkos. But that's just me being silly about something no-one will ever see!

I did add some extra filtering to the TBA820Ps and have attenuated the headphone out a bit to reduce the noise on minimum volume.

If you've got a 50Hz hum, how are you powering it? Through AutoRadio with a PSU, or with the Z131 mains adaptor? I did replace the large capacitor in the Z131 (reservoir?), and had to do some work on the 600 Power Supply board too. Doesn't this suggest (and I'm grasping at half-understood technicalities here) a filter or decoupling failure between the power rail and the signal?
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