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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc. |
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9th Jul 2020, 12:59 pm | #1 |
Pentode
Join Date: Sep 2017
Location: London, UK.
Posts: 115
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Revox A77 Playback Problem
Hi, I have a Revox A77 which I'm trying to get working again. It's got an issue with one of the Repr Amps. It was completely dead with no playback at all. I've changed the tantalum capacitors as two of them had shorted and also the electrolytics. There is now playback when I select 'input' but not from the tape. If I swap the card for a good one I get playback from input and the tape. I don't have a scope so can't test it properly. Is there a part or parts that could cause this issue? Thanks Christian
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9th Jul 2020, 11:49 pm | #2 |
Moderator
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,224
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Re: Revox A77 Playback Problem
Transistors have been known to fail, i suppose resistors could go high, A more likely cause is the preset pot for the reproduce level. The slider breaks off so you get no output. Its a simple thing to replace.
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10th Jul 2020, 6:13 am | #3 |
Octode
Join Date: Jul 2006
Location: Perth, Western Australia
Posts: 1,969
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Re: Revox A77 Playback Problem
To add, as always check the polarity orientation of the capacitors you have replaced.
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10th Jul 2020, 7:30 pm | #4 |
Pentode
Join Date: Sep 2017
Location: London, UK.
Posts: 115
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Re: Revox A77 Playback Problem
Thanks. It was the preset pot. It looked fine but wasn’t making contact. Now it’s fallen apart completely.
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