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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 7th Oct 2021, 6:32 pm   #1
Jolly 7
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Default JVC boombox cassette playback issues

Hello. I have a JVC 9475LSB boombox which is currently experiencing issues playing back cassettes. At times cassettes will play fine. However, most of the time the play button will pop right back to the off position. From what I can make out, the issue seems to be with the take up mechanism on the left hand side which is not rotating freely when I press the play button. The capstan and pinch roller are rotating freely though.
Does anyone have any suggestions as to what is the most likely cause of this issue ? I am attaching a picture and can attach a few more if required. Thanks in advance.
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Old 8th Oct 2021, 1:34 am   #2
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Default Re: JVC boombox cassette playback issues

Presumably under fault condition the take up is nonexistent or intermittent?

Could be a bad belt, or rubber idler tyre. You'll have to open it up and take a look.
I have also seen this caused by a sticky tape end stop 'feeler'. Given that it sometimes works okay, this would seem likely.
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Old 8th Oct 2021, 6:18 pm   #3
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Default Re: JVC boombox cassette playback issues

Thanks. I already had replaced the old belts with new ones, so ruled them out. I have posted a picture of what could be the root cause of the playback issue. I think the metal spindle , which I have circled, ought to be making contact with the rubber of the take up spool in play mode, but it's not doing that after I cleaned the spindle. It could be that the rubber 'tire' has worn out or there was a small rubber grommet type part, which has degraded over time, thereby initially allowing intermittent contact with the tire. I might try fitting a tiny rubber O ring around it temporarily to see if that solves the problem.
The take-up is now non-existent after cleaning.
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Last edited by Jolly 7; 8th Oct 2021 at 6:19 pm. Reason: Take up issue described.
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Old 10th Oct 2021, 10:34 am   #4
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Default Re: JVC boombox cassette playback issues

This JVC model was covered in the E&E trader sheets numbers 3222 and 3223, there probably is a service manual but I don't have copy, it was also in a JVC compilation book 'B' of the 1970's but that publication only covers circuits, no mechanisms shown.

If you have dismantled the mech for cleaning, it's possible that you have a spring in the wrong position, either on the rubber jockey wheel or the arm with the brass drive shaft.

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Old 11th Oct 2021, 10:09 pm   #5
Jolly 7
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Default Re: JVC boombox cassette playback issues

@Dave. I found out the problem. It wasn't because of the slightly worn rubber idler on the take up wheel. It was because the pause button had a spring that was sort of stuck halfway, preventing the rotating brass shaft to make contact with the idler tire. My cassettes are playing once again with bright sounds and at the right speed, but there's also another issue I am facing. After playing cassettes for a while, some of the tape is getting inside the cassette body, causing the player to stop. I think this could be down to a shiny and hardened pinch roller. Maybe I should replace it with a new one.
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Old 12th Oct 2021, 1:15 am   #6
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Default Re: JVC boombox cassette playback issues

Quote:
Originally Posted by Jolly 7 View Post
. After playing cassettes for a while, some of the tape is getting inside the cassette body, causing the player to stop. .
I don't know what you're trying to say there. Surely the tape should always be inside the cassette body or it would get tangled?

If you mean the take up is weak, then give the rubber edge of the spindle in your photo a rub with sandpaper. As the spool fills up, you will find the take up gets worse and tape will eventually spill out into the machine.
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Old 12th Oct 2021, 1:25 am   #7
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Default Re: JVC boombox cassette playback issues

@Ben. Some of the tape got accumulated inside the cassette shell immediately to the left hand side of the felt pad and brass spring. I do not know if the cassette itself might have problems. Anyway, I have now disassembled the pinch roller. It's degraded as you might be able to make out.
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Old 12th Oct 2021, 10:20 am   #8
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Default Re: JVC boombox cassette playback issues

It's a bit barrel shaped/glazed, but if it isn't cracked you can restore the grip by using fine sandpaper. Just make sure you don't rub too long in one location.

If the tape is accumulating this is likely a take up problem, though. If the pinch roller were sticky, the tape would wrap itself around it. Similarly, if the roller is hard/glazed, the tape will get creased as it passes and you would definitely notice the audio coming and going.
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Old 16th Oct 2021, 12:26 am   #9
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Default Re: JVC boombox cassette playback issues

I was fortunate to procure a new pinch roller assembly and decided to use some of the parts from it. However, it was quite a difficult job to replace and it involved some fine drilling, cutting, sanding etc. The old pinch roller shaft was completely stuck and after removing it I had to fit the slightly wider shaft for the new roller. After fitting this, I have no more of the previous problems and all my cassettes are playing back fine.

Here's a picture of the new pinch roller and modified assembly. If all continues to go well, I will put back everything together in the cabinet and close it.
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Old 28th Oct 2021, 4:14 pm   #10
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Default Re: JVC boombox cassette playback issues

All is fine after my repairs to the cassette section of this boombox. The play, fast forward, rewind and even record functions work as they should. Moderators please close.
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