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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 14th May 2018, 8:15 pm   #1
ckbrooks
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Default Uher 4000L running too fast

I have a Uher 4000L running from a z124 power supply, which seems fine in all respect apart from it is running too fast.

If I playback a recording made on a fully restored machine, known to be working, it plays back considerably faster.

Any thoughts on how I could fix this? belts are new btw.

Thanks again

Clive
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Old 15th May 2018, 11:41 am   #2
barretter
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Default Re: Uher 4000L running too fast

The Uher 4000L's speed is controlled electronically by a small circuit-board close to the motor [see image]. I assume that by turning the indicated potentiometer you can change the speed, but of course there might be something more seriously wrong with the circuit.
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Old 15th May 2018, 12:00 pm   #3
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Default Re: Uher 4000L running too fast

I think the pot will only adjust the speed slightly so it may not solve your problem of "considerably faster". Also make a note of the position of the pot's slider so you can put it back to its original state if moving it doesn't make a difference.
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Old 15th May 2018, 12:09 pm   #4
ckbrooks
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Default Re: Uher 4000L running too fast

Thank you very much indeed, I’ll try that carefully as a first step!

Clive
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Old 16th May 2018, 8:05 am   #5
barretter
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Default Re: Uher 4000L running too fast

It could be that the picture I posted was of a Uher 4000S but there should still be a circuit-board near the motor with an accessible pot. It could be mounted vertically rather than horizontally.
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Old 22nd May 2018, 9:18 am   #6
ckbrooks
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Default Re: Uher 4000L running too fast

I’ve tried slowing the speed down with the pot, but it is still running too fast - about a semitone or so in musical language. I’m at a loss of what to do next, and would be very grateful for any help. The machine is perfect apart from this niggle. Thanks.
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Old 22nd May 2018, 9:20 am   #7
ckbrooks
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Default Re: Uher 4000L running too fast

Here’s the bit of the circuit board with the speed control pot on it...
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Old 22nd May 2018, 10:26 am   #8
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Default Re: Uher 4000L running too fast

Presumably you'e talking about the single pot at the top of the picture. Turning that counterclockwise should slow the motor. If it doesn't there may be something wrong with the circuit board.
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Old 22nd May 2018, 12:23 pm   #9
ckbrooks
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Default Re: Uher 4000L running too fast

Thanks for coming back to help. The pot is already turned to its minimum setting. What I’m looking for now is what to do next with the board. There seems to be two right next to each other. I’m not sure how they come out at the moment, any help grateful received. I’d like to get this machine sorted.
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