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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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7th May 2020, 9:46 am | #1 |
Triode
Join Date: Jul 2014
Location: Stonehouse, Gloustershire, UK
Posts: 46
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Pioneer CT-740 Playback Noise
I am puzzled by the noise that this cassette deck produces on playback.
It sounds like static discharges that you might hear on a vinyl record. The file I have attached contains a .WAV file demonstrating the noise coming through the audio output when play is pressed with no cassette in the drive. When a cassette is played the noise is superimposed on the audio from the cassette. When anything is recorded onto a cassette and the cassette is played back on another machine the noise is not present so it only occurs on playback. I have played a different cassette deck through the same audio channel on the amplifier and the noise does not occur. If anyone has any ideas what might be causing this I would be very grateful to hear them.
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Tony G4CMY G-QRP-C No 57 FISTS No 1626 Last edited by G4CMY_Tony; 7th May 2020 at 9:49 am. Reason: Additional information |
7th May 2020, 11:35 am | #2 |
Octode
Join Date: Jul 2006
Location: Perth, Western Australia
Posts: 1,965
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Re: Pioneer CT-740 Playback Noise
A little unusual.
I'm not saying this is what it is but I had a similar clicking sound with a Sony cassette recorder, also only on playback. This Sony deck had a moulded plastic chassis for the mechanism. In the end it was a static buildup from the capstan shaft, occasionally discharging to deck ground. The solution I came up with was a piece of wire grounding the capstan shaft. |
7th May 2020, 11:41 am | #3 |
Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
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Re: Pioneer CT-740 Playback Noise
Yes does sound like static possibly. If you select Pause when playing does the noise stop, i.e. is the noise only present when tape moving ?
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7th May 2020, 12:09 pm | #4 |
Triode
Join Date: Jul 2014
Location: Stonehouse, Gloustershire, UK
Posts: 46
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Re: Pioneer CT-740 Playback Noise
Thank you both for your input.
Yes it does stop when the pause button is pressed. I'll have a go at grounding the capstan shaft. Many thanks.
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Tony G4CMY G-QRP-C No 57 FISTS No 1626 |
8th May 2020, 11:48 am | #5 |
Triode
Join Date: Jul 2014
Location: Stonehouse, Gloustershire, UK
Posts: 46
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Re: Pioneer CT-740 Playback Noise
Just an update.
I tried grounding the capstan shaft and it made no difference, even though it was a prime candidate - It rotates through a brass bush which is supported in plastic casting and the flywheel rotates against a nylon block thrust bearing. I did, however manage to track down the problem it was cured by grounding the casing of the record/playback head. That was screwed to a plastic moulding too. Problem solved and, having replaced the drive belts, I can now start digitising my old cassettes which is what I bought it for anyway. Thanks once again for your help.
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Tony G4CMY G-QRP-C No 57 FISTS No 1626 |
8th May 2020, 12:47 pm | #6 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,820
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Re: Pioneer CT-740 Playback Noise
Well done, it's nice when there's a simple cure.
I wonder whether there was an official mod? Or was it wrongly repaired in the past? |
8th May 2020, 1:03 pm | #7 |
Triode
Join Date: Jul 2014
Location: Stonehouse, Gloustershire, UK
Posts: 46
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Re: Pioneer CT-740 Playback Noise
Well everything looks to be untouched and in accordance with the service manual that I have dated April 1983 (which matches well with the dates on various components) so I don't think it has been repaired in the past. However, it does seem odd that an issue like this was allowed to go out.
I know very little about Pioneer equipment (although I know a bit more now ) No doubt someone on this learned forum will have some knowledge.
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Tony G4CMY G-QRP-C No 57 FISTS No 1626 |
8th May 2020, 1:21 pm | #8 | |
Octode
Join Date: Jul 2006
Location: Perth, Western Australia
Posts: 1,965
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Re: Pioneer CT-740 Playback Noise
Quote:
Pioneer used a plastic chassis on a number of their mechanisms including the the CT-F series. |
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