Sharp GF555. What would you do if........

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Beosystem10

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Feb 21, 2013
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...you'd had one in bits for a few days awaiting some more free time to progress the task and had found that the idler tyres were perfect?

This is the dilemma facing me. A friend who has long lusted after my own GF555 brought her own recent car boot sale purchase to me as it wasn't taking up the slack on either deck and she wanted me to fix it for her.
I extracted the cassette decks and separated the plates, fully expecting to find that it needed idler tyres and the square belts as my own example did when I bought that a good few years ago. Perhaps unsurprisingly, I found the telltale black molten rubbery stuff on the capstans when I pulled the flywheels out so this 555 also needed capstan sleeves, no problem as I still have some nice pink silicon RC fuel line left from doing my own 555 some time ago. I say "some", the stuff came by the yard and I'd used under an inch of it! :lol: so I soaked the capstan bush holders in cellulose thinners overnight to get rid of the last of the old sleeves and set about cleaning the remaining "goo" off the hub flanges and removed the idler tyres to clean up the rims of their idlers. I soaked the tyres in a glycerine-based rubber cleaning solution that I always use on such things as it preserves their softness and doesn't dry out the rubber in the way that long term exposure to IPA or similar would do.
Then, after the tyres had been soaking in that stuff overnight, I wiped them dry with a cloth and not only was there no signs of their degrading in the way of the capstan sleeves, they were supple, clean and smooth and - had this been for my own machine - I wouldn't have hesitated to refit these tyres and use them with the [new capstan sleeves] that are going into this 555.
Every trace of the totally shot sleeving is gone, every contact surface can now be touched without getting liquid rubber all over my fingers and the original tyres have a tenacious grip against the capstan sleeves and the hub flanges so they'll work just fine once the machine is reassembled and the square belts are done, (the flat pair are fine and were both riding correctly on the motor pulleys and flywheels so will be reused).
So, what would anyone else do here? I'm 99% confident that the old tyres are good to go since they now feel, look and even smell fresh but has anyone any bad experience of poor idler tyre life after reusing in this way? The owner of the other GF555 is an old friend and she travelled a long way to drop the box off with me so on the one hand, everything must be right but equally, she doesn't have cash to throw around so everything must also be as cheap as it's wise to make it.

Some pics taken before getting the last of the black goo out of the way:

Old removed, one new one fitted to check the size, check the rubbery slime on that capstan:

Not short of tyres if I end up being persuaded to fit new ones:


Yes, those are O rings, but the difference is only really the difference between a car tyre and a motorcycle tyre; contact area in one plane, and I've used these on many previous similar operations without any trouble. Size isn't critical as long as they're a good fit on the rims since idlers don't affect the overall gearing. :-)
 

doctork

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Oct 21, 2015
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John


Thanks for pointing that out very clearly. Came accross you posting while servicing my gf555, and guess what: the same black stuff on my capstans. Sorry for being 2 years late.

I was prepared to refit the tyres, but my o-ring set from bauhaus (austria) was no good - to small in the first place (sorry no photo) and far to fat on my second attempt:


IMG_9368.JPG


Well it turned out that these were far too fat. So it seems: size does matter.

Found these on amazon:

71WMgj-sWmL._SL1500_.jpg

Seems to be exactly your box!

While ordering, question is: what size did you choose?


Best Greetings - Clemens
 

k2j

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Mar 28, 2011
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Props that is no easy deck set to tear down that far. I like your avatar is that C64 impossible mission? I played that in the 80s all the time!!
 

doctork

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Oct 21, 2015
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Yes, Impossible Mission, whilst standing before that console. I still remember clearly, that guy where I played this game first hat a b/w TV screen hooked up on his C64 - impressive.
 
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