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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 13th May 2023, 2:53 pm   #1
nawaz bashir
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Default Sharp GF-9090 cassette player playing slow

Hello,

I'm restoring my dad's old cassette player and have replaced the belts and it's running slow. I have checked all the components and everything seems to be intact and working. The only thing I'm thinking is that the motor is worn out as I have replaced the belt and it's running slower than before. I'm not sure what to do and wondering if anyone has had the same issue and how to fix it.

Also, does anyone know where I can go to get this restored in the UK?

Thanks
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Old 13th May 2023, 10:56 pm   #2
Analogue man
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Default Re: Sharp GF-9090 cassette player playing slow

Is the new belt too tight? if it is that would cause the problem, alternatively it may be that the speed of the motor (which is often adjustable) has gone out of adjustment either due to the trimer potentiometer failing or because a fixed resister in the motor speed control has gone high resistance and that is where I'd look after confirming that the belt isn't too tight.
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Old 14th May 2023, 10:35 am   #3
paulsherwin
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Default Re: Sharp GF-9090 cassette player playing slow

Graham is spot on. It's unlikely that the motor is faulty.
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Old 14th May 2023, 10:40 am   #4
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Default Re: Sharp GF-9090 cassette player playing slow

Apart from the belt, it's worth giving the mech a basic 'clean & lube' - motor bearings (if accessible), capstan bearings and so on.
And as Graham says, the motor control may be suffering from duff resistors, especially the speed adjustment pot. If it doesn't use electronic speed control, suspicion falls on the mechanical governor inside the motor body. Often the centrifugal switches get oxidised.
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Old 14th May 2023, 1:50 pm   #5
nawaz bashir
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Default Re: Sharp GF-9090 cassette player playing slow

Hello guys,

Thank you so much for your responses, it is really appreciated. I don't have much knowledge of electronics so some of the stuff sounds too complex and in-depth for me.

I have cleaned out as much as I can and lubricated all the mechanics as much as I could. I have bought a new belt and compared the sizes, the original belt is 5 1/2 inches and is loose and the new one is 5 inches which I think is too small causing the cassette to play slow and assuming there may be too much tension. I've tried running the motor without the belts on and it's running smoothly and really fast. As for the motor, it is completely encased, and can't see how I can get into the motor to lubricate or have a look at it.

Would buying a 5 1/4-inch belt help? or would buying a replacement motor be needed? Would you know where I could buy one in the UK?

Thanks,
Nawaz
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Old 14th May 2023, 10:18 pm   #6
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Default Re: Sharp GF-9090 cassette player playing slow

Try a 5 1/4 belt, it doesn't sound like there is a problem with the motor but you never know, try another belt and if no good at least it won't have cost much.
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Old 14th May 2023, 10:19 pm   #7
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Default Re: Sharp GF-9090 cassette player playing slow

The other common problem this Sharp cassette mechanism suffers from is the rubber idler hidden below the capstan which drives the take up reel. It rots away, resulting in a deck which mostly works but stops after a few seconds leaving a loop of loose tape. I have a GF-6500 which uses the same mechanism in which someone had found a creative way of fitting the belt so that the take up reel was sort-of driven. It played tapes, but not well, and not at the right speed.

Make sure the belt is correctly fitted, and the take up drive is working properly.

Chris
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Old 15th May 2023, 8:56 am   #8
nawaz bashir
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Default Re: Sharp GF-9090 cassette player playing slow

Thanks I will try a new belt and give the works another clean and lubricating it maybe I have missed something. Thanks again, guys.
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Old 15th May 2023, 10:17 am   #9
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Default Re: Sharp GF-9090 cassette player playing slow

Did you understand what Chris was talking about in post 7? It's worth checking that this is OK, as if it's gone sticky, it could cause all kinds of funny symptoms.

Basically, it's a bit of rubber sleeving, slipped over the capstan shaft, between the two parts of the capstan's front bearing. Easier to see than describe!

There is a picture of the part on the right side of this picture on an auction listing: https://i.ebayimg.com/images/g/oEMAA...XM/s-l1600.jpg

And look at point 7'07" in this nice YouTube video. Not the same deck, but illustrates what Chris was referring to: https://youtu.be/DzWjdAMfh94
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Old 15th May 2023, 10:51 am   #10
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Default Re: Sharp GF-9090 cassette player playing slow

I've found some photos I took of correctly fitted belts on a GF-6000 I refurbished last autumn. I know they're right because I referred to the service manual and the deck plays cassettes properly. There are three belts. On the top side, one drives the counter from the take up reel, and the other drives the wiggly-waggly auto-stop mechanism from the capstan. On the bottom side, the big flat belt drives the capstan from the motor.

Again, note that the take up reel is not driven by a belt but by idlers from the rubber bit on the capstan. It's nearly mpossible to take a photo of because it's tucked under the top-side capstan bearing, and can only be replaced by removing the capstan and flywheel (which isn't actually that hard to do by removing the plate on the back, but take care with the positioning of the music-search-stop solenoid Which has to be removed - it's described in the manual).

Chris
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Old 15th May 2023, 3:54 pm   #11
nawaz bashir
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Default Re: Sharp GF-9090 cassette player playing slow

Hi I have changed the sleeve and three belts and the pinch roller I will check everything again to make sure I have not missed anything I will take my time so not to make a mistake thank you for the photos.
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