Quad 33/303 right channel audio suddenly disappears

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11-Oct-2019 10:38 AM

Copacabana

Copacabana

Posts: 5

Hi there,
a few months ago I had a problem with Quad 33 pot that didn't switch off anymore. An electronic miracle happened and the problem solved just by opening the preamp, checking it and closing it (maybe it was a faulty contact).
Now, after a few months, there's a brand new problem: after a few seconds of music the right channel shuts off. I switch the Quad 33 off/on again and it comes back, then disappears, then it keeps playing for minutes and it disappears again.
In your opinion is it another potentiometer (maybe the same) problem or somethin more serious, maybe related to left/right switches?

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14-Oct-2019 03:16 AM

EJP

EJP

Posts: 1669

Start with the simple things. Check the seating of the boards. Check all six solder joints at the volume pot. Interchange the two amplifier boards to see if the problem changes channels.
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15-Oct-2019 02:49 PM

Copacabana

Copacabana

Posts: 5

after a few tests I realized that it happens only with "tape" source...is it the board?
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16-Oct-2019 01:29 AM

EJP

EJP

Posts: 1669

Despite its name, everything goes through the Tape Adapter Board. I would start at the Tape socket itself and ensure continuity all the way from there through the Tape switch to the multiway socket the board seats into. Fighting your way around the switch circuitry on the PCB is no fun but it can be done. Also check the cable you're using.

EJP

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