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General Category => Technical Support - General => Topic started by: Spirantho on 14:50, 23 September 21

Title: Idler tyres on CPC464 datasette
Post by: Spirantho on 14:50, 23 September 21
Hi everybody,

I recently had a '464 in for repair, with the symptoms being that it could rewind and fast-forward, but when it played, it would just get stuck.

So I recapped the machine, changed the belt, started up the Amstrad, and readied myself for a nice little bout of Jet Set Willy.

Except the datasette had other ideas.... it turned a bit, and then got stuck!

A quick prod and probe later, and I found the culprit, which was the idler tyre (I tried to attach a photo, hope it appears). The tyre had not only degraded, but someone had attempted to glue the decayed bit back on the wheel again! As you can imagine, this didn't help. So I had to find a replacement tyre...

There is a website called FixYourAudio.com which, as luck would have it, has idler tyres. So I sent some hard-earned dosh over to Slovakia in exchange for a selection of idler tyres to try.

The purpose of this post is to report on my findings....

After trying various tyres, I found most of them too small (the idler tyre didn't grip the cog) or too large (the idler tyre hit the plastic post which guides the Play mechanism).
I found the best fit was the one labeled "Idler Tire 9.3x14.8x2.05mm". This one is only a fraction too wide on its outer circumference, and would turn most of the time, but also rubbed against the plastic post for the guide mechanism. The solution I found was to take a craft knife to the plastic post and just shave off a tiny amount (about 0.5mm) of the plastic post where the idler tyre rubs against the post. It doesn't affect anything else if you're careful as you're only making it a tiny bit thinner where it rubs against the post.

Obviously ideally there would be an idler tyre that's a perfect fit - but in the meantime I'm hoping the above info may be useful for someone with a failed idler tyre and no way to replace it, and at least means people don't have to buy loads of tyres from Slovakia in an effort to find one that fits. The datasette I have here is now working, but is noisy; I think that's because of damage to the idler wheel caused when they superglued bits of rubber to it, though.

Naturally I can take no responsibility for anyone messing up with a craft knife and an Amstrad :) And of course your mileage may vary, but it did work for me, so hopefully may help others.

Title: Re: Idler tyres on CPC464 datasette
Post by: matburton on 11:27, 17 November 21
Thanks for the detailed write-up!

My deck is in a very similar starting state, so I'm going to try to reproduce your fix  ;)

(https://i.imgur.com/1xv1pLMm.jpg) (https://i.imgur.com/1xv1pLM.jpg)
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