Sharp GF-9696 Idler Wheel

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ElectroKid

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Jun 7, 2015
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Hi,
Just cleaning the tire as I have a slight wobbly playback and also there seem to be a 'bump' that cause the takeup to slightly stop as it keeps turning - a bumpy ride...
Then I found something interesting:
Is it normal to have the inside of the plastic wheel covered with sticky paper tape couple of turns? - see pic
I guess some tech put it in there to 'widen' the rubber diameter so it grips more...
Should this sticky tape stay or should it go?
 

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BoomboxLover48

BoomboxLover48

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Dec 3, 2010
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This wheel was slipping that is why the former tech increased the inner diameter of the wheel with that tape. This way the rubber will get more contact to the flywheel axis rubber sleeve that makes contact with this idler.

You might have to change the flywheel axis rubber (went bad on all 9696s I have) with a thin gasoline tube that you can buy from hobby shops.

The other option is to get a new idler wheel and replace the old one. You can also use rubber O rings or rubber washers that match the size. I would take it to a local plumbing shop and see what they got.

https://boomboxery.com/forum/index.php/topic/17726-sharp-gf9696-drive-rebuild/?hl=%2Bsharp+%2Bgf9696
 
superlew

superlew

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BoomboxLover48 said:
This wheel was slipping that is why the former tech increased the inner diameter of the wheel with that tape. This way the rubber will get more contact to the flywheel axis rubber sleeve that makes contact with this idler.

You might have to change the flywheel axis rubber (went bad on all 9696s I have) with a thin gasoline tube that you can buy from hobby shops.

The other option is to get a new idler wheel and replace the old one. You can also use rubber O rings or rubber washers that match the size. I would take it to a local plumbing shop and see what they got.

https://boomboxery.com/forum/index.php/topic/17726-sharp-gf9696-drive-rebuild/?hl=%2Bsharp+%2Bgf9696
Click to expand...
Ditto. :yes:
 
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ElectroKid

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Jun 7, 2015
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Thanks guys,
I slipped in an RC tube on the capstan and used some O-Rings assortment I found. It's not perfect with some slight warble sound...slowly getting there fine tuning those rubbers... tape at the beginning of the side getting moved off-center (off-azimuth, just before reaching pinch roller/needle area) but it gets centered again after a minute in or so. I'm using 5.5mm OD RC tube (edges sanded/rounded) but still seems a bit of tight fit..., length is 6mm (that's the max I could squeeze tru the bearing window...(how did you take apart the lower bush?)

Another issue: when APLD buttons pressed, the play button is getting kicked (ie not staying in play mode hence gap search not performed..) this also happens when momentarily pushing down FF or RW while play...
Seems like playback is not engaging good enough and the slightest touch gets it disengaged
On the same issue, do you usually clean the old white lubrication stuff (turned to semi hard crust...) I think I cleaned some I shouldn't on the way from the brass mechanics of these knobs - any suggestion will be much appreciated.
 
BoomboxLover48

BoomboxLover48

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Dec 3, 2010
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The lower bush is not easy to remove. I wrapped thick paper on it and used a nose pliers. We should use only minimum force or else I was afraid it will bend it. I always try to turn a bit and then pull. It worked but somehow I left a scratch on the rim of it with all the care I took. If the O ring is a little shorter it wont grab on to the RC tube on the capstan axis. I would try one a bit more bigger in diameter.

Even if you change the O ring and the RC tube the diameter of these wheels can be slightly off from the manufacturers specs so tape may not play at the correct speed. Luckily 9696 has that motor speed adj at the lower middle part of the front section.

Check the tape you used. May be the reel is a bit right. This could cause that shut off.
 
J

jimmyjimmy19702010

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May 5, 2012
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Good quality tubing is the key to a good result on these decks - 5mm OD, 2mm ID - the slight increase and decrease in speed caused by poor quality tubing can be one of the many causes of warbled sound on these decks. You don't need anymore than 5mm of tube length.

You need just enough to make contact with the tyre allowing for some end float of the flywheel. Ensure none of the tubing you fitted is rubbing on the bearing housing. BTW, there is no need to remove the bearing housing to fit the tubing.

All the sliding surfaces of your deck need cleaning and lubing to operate normally.

The Sharp decks of this era really are robust and can be made to play really well with a little maintenance.

James... :-)
 
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ElectroKid

Member (SA)
Jun 7, 2015
55
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Thanks James this very good input as I had the feeling my tube is slightly wider and prbbly touching the housing walls... imma go and try to find 5mm OD and 2mm ID.
Also what stuff do you use for lubrication of the inner moving parts of the tape like brass metal sliding against eachother?
I have some clear silicon grease but seems too runny and migrating features...not the right consistancy like orig white paste.
 
hopey

hopey

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Dec 28, 2014
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That p

ElectroKid said:
Thanks guys,
I slipped in an RC tube on the capstan and used some O-Rings assortment I found. It's not perfect with some slight warble sound...slowly getting there fine tuning those rubbers... tape at the beginning of the side getting moved off-center (off-azimuth, just before reaching pinch roller/needle area) but it gets centered again after a minute in or so. I'm using 5.5mm OD RC tube (edges sanded/rounded) but still seems a bit of tight fit..., length is 6mm (that's the max I could squeeze tru the bearing window...(how did you take apart the lower bush?)

Another issue: when APLD buttons pressed, the play button is getting kicked (ie not staying in play mode hence gap search not performed..) this also happens when momentarily pushing down FF or RW while play...
Seems like playback is not engaging good enough and the slightest touch gets it disengaged
On the same issue, do you usually clean the old white lubrication stuff (turned to semi hard crust...) I think I cleaned some I shouldn't on the way from the brass mechanics of these knobs - any suggestion will be much appreciated.
Click to expand...
Sounds like you need extra tension on the pinch roller spring. This affects the tape alignment remove and bend with plyers.

Another issue can be the spring for the idler assembly

Last one is the rubber on the idler I tried to use replacements but ended up using the original as the tolerances are so tight. This is just take up on the cassette spool as long as you replace the noodle and have a good spring attached should be good.
 
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