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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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Old 24th Oct 2019, 4:35 am   #1
Ken Clark
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Default Revox A77 Tape loose

I recently replaced components on the speed control board which fixed the speed control problem I was having.
However now the take-up (right hand) reel is not maintaining tension on the tape.
Any clues?

ken
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Old 24th Oct 2019, 12:22 pm   #2
Marotick
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Default Re: Revox A77 Tape loose

I think you should also replace parts on the relay board

Jack Marotick
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Old 24th Oct 2019, 2:57 pm   #3
ms660
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Default Re: Revox A77 Tape loose

Is the rewind motor providing back tension in play mode?

Lawrence.
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Old 24th Oct 2019, 9:47 pm   #4
Michael Maurice
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Default Re: Revox A77 Tape loose

Check that the MOTORS OFF button is not pushed in.

Check continuity across the switch contacts
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Old 29th Oct 2019, 4:28 am   #5
Ken Clark
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Default Re: Revox A77 Tape loose

Many thanks for all of your replies.

Here is what is happening in each mode:-

Play
Take up spool not keeping tension on the tape. Also it only works whilst the button is pressed (i.e not latching)

Rewind
Working O.K. but it only works whilst the button is pressed (i.e not latching)

Fast Forward
Rewinds at what appears to be 'Play' speed. Again it only works whilst the button is pressed (i.e not latching)

ken
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Old 29th Oct 2019, 9:37 am   #6
ben
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Default Re: Revox A77 Tape loose

Remote plug loose, or wire disconnected there?
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Old 30th Oct 2019, 12:31 am   #7
Michael Maurice
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Default Re: Revox A77 Tape loose

As Ben says, check that the remote dummy plug is fitted. if it is check the End Of Tape sensor and the two transistors connected to it.

I also suggest you replace the two 4.3uF reel motor run capacitors and the 3.5uF capstan motor run capacitor.

You can get them from Revox online and/or Nagravox
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Old 30th Oct 2019, 6:41 am   #8
Ken Clark
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Default Re: Revox A77 Tape loose

Thanks again everybody

I must admit I didn't realise that the dummy plug was part of the circuitry so putting that back fixed the latching problem. Thanks.

I will purchase the three capacitors as suggested Michael and let you know how that goes.

ken
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