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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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19th May 2016, 5:36 pm | #1 |
Diode
Join Date: May 2016
Location: Rotterdam, Netherlands
Posts: 9
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JVC HR-S5000E VCR with elusive rewind problem.
Hello everybody, thank you for your willingness to give your attention to a problem that has seemed to in-solvable for some time now...
This, otherwise perfectly functioning, VCR has become useless because it fails to rewind the tape completely. More precisely: When the RH spool is completely full, it will ramp up and start the fast rewind. After about 1/2 to 2/3 of it's mission the rewind process stops. It's just switched off. In a rare instance it will completely rewind to an empty R/H spool, but that is a rare occurrence. When the rewind stops and I give it another prompt it will do a short ramp up and immediately stop again. This in less than a second. The unit has been to two (!) repair shops. They're in the dark. The usual renewal of the idler drive wheel has been done, but to zero effect. Fast Forward works without a glitch. It's only in the rewind that the gremlin does it's work. All felts and bands have been checked and cleaned. I'm only a radio and LF audio man and whilst I have procured the workshop manual, I've come to the conclusion that this is a bridge too far for me. However I'm convinced the problem is an electronic one. Not mechanical. It seems that there are very experienced and knowledgeable technicians on this forum and I hope that either one of you can direct me to the cause of this nasty defect or, alternatively, I would be extremely pleased if anyone would be prepared to have a go at it on the bench. I have a spare unit for parts that does'nt have this particular problem, that I could send over with the nr.1 patient. Naturally I'd be fully prepared to cover any time / parts cost. The VCR is otherwise low hours and I've inherited it from a dear friend and it's a part of my set-up that's very much appreciated and I'd love to get it back in good order. Looking forward to your replies... Rob. |
19th May 2016, 8:04 pm | #2 |
Octode
Join Date: May 2003
Location: Belper Derbyshire
Posts: 1,935
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Re: JVC HR-S5000E VCR with elusive rewind problem.
Good evening,
I presume you have tried different cassettes in case the one you are using is binding internally and causing an overload protection to activate. Christopher Capener
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Interests in the collection and restoration of Tefifon players and 405 line television |
19th May 2016, 8:11 pm | #3 |
Diode
Join Date: May 2016
Location: Rotterdam, Netherlands
Posts: 9
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Re: JVC HR-S5000E VCR with elusive rewind problem.
Yes, your assumption is correct: I've tried everything under the sun in the mechanical arena. Wish it would have been so simple. Still, I can see your point because the rewind stops at some point, say halfway where the required tension on the take-up reel would have increased. But indeed it has been checked with different cassettes and new or old makes no difference at all. It's not a cassette problem.
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19th May 2016, 8:14 pm | #4 |
Dekatron
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,208
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Re: JVC HR-S5000E VCR with elusive rewind problem.
Some VHS machines (and I think some JVCs did this) had some kind of sensor (often an optoelectronic device, LED and phototransistor) operated by each spool spindle. The control electronics, by seeing the relative frequencies of the signals from the 2 sensors could work out how much tape was on each spool, estimate how much recording time was left on the cassette, and so on.
I wonder if there is a problem in that area and the the thing thinks it's full rewound when it's not. Maybe removing the reel drive turntables and cleaning the sensors and the reflective bits on the turntables (if it is reflective, some certainly were) would help. |
19th May 2016, 9:47 pm | #5 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,932
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Re: JVC HR-S5000E VCR with elusive rewind problem.
May be a lower drum problem and can be cured by polishing with Brasso or Swarfega.
Just watch the upper head drum when doing it.
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