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Sony direct drive turntable platter issue

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david04

New Member
Hello,

I own a second-hand Sony PS 4750 direct drive turntable.
Under the platter is located a sensor (looks like a tape head) that sits close to a magnetic coating located under the platter (so it keeps a constant speed). Some of the coating seems to have scratched off, so the turntable produces a lot of wow and flutter.
Will repainting a new layer of magnetic coating over the existing one solve the problem? What type of coating do I need?

Thanks a lot,
David
 
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Good luck with that. I don't know if you can recoat that. I certainly have never heard of it being done. You might have to track down a replacement platter.
 
Montycat said:
Good luck with that. I don't know if you can recoat that. I certainly have never heard of it being done. You might have to track down a replacement platter.
Click to expand...

Hate to tell you this. But that platter is permanently damaged. No undoing that damage. Find a parts unit of the same model you have, buy the platter off that, which should get you back to where you began. A major thing I dislike about Sony and Denon DD which use this type motor.
 
KentTeffeteller said:
Hate to tell you this. But that platter is permanently damaged. No undoing that damage. Find a parts unit of the same model you have, buy the platter off that, which should get you back to where you began. A major thing I dislike about Sony and Denon DD which use this type motor.
Click to expand...

Tell the other guy!
 
david04 said:
Hello,

I own a second-hand Sony PS 4750 direct drive turntable.
Under the platter is located a sensor (looks like a tape head) that sits close to a magnetic coating located under the platter (so it keeps a constant speed). Some of the coating seems to have scratched off, so the turntable produces a lot of wow and flutter.
Will repainting a new layer of magnetic coating over the existing one solve the problem? What type of coating do I need?

Thanks a lot,
David
Click to expand...

That coating won't help you. That speed control pattern is recorded at the factory. You have one viable option. Find a parted out Sony DD turntable of the same model, and buy it's platter. That should get you back in business. Make sure that tape head does not come near touching the platter. Allow a credit card's space between read head and the platter's magnetic coating.
 
Wow! I didn't expect so many answers in a few hours' time, thanks to all of you!
So from what I can tell, there's no solution to repair that coating, and I should try and find a spare platter. Had a look around the web, and seems none are available for sale... :(
Another thing I noticed is that Wega made one, that looks exactly the same as the Sony one: the P4410.
Does anyone know where I could get a spare platter from please? Or how I could get this one fixed?
Thanks!
 
@david04 - suggest you start searching eBay. May not be one there now but eventually there will be. There is also a sponsor here, organdonorparts.com that sells turntable parts. You could check there. Sounds like you want others to do the searching and work for you.
 
When the system is working right, it works great. Unfortunately, any damage to the pattern recorded in the coating (say from a magnet) or to the coating itself, turns the system into a doorstop. I've sometimes wondered if some DIY repair was possible, but it wouldn't be worth the effort. It would be possible to recoat the ID of the platter, but then you'd have to spin it perfectly evenly and re-record the pattern. Or, you'd build a fixture with a zillion permanent magnets and slide the platter over it. Or, make a wheel with fewer permanent magnets, of exactly the right diameter, and roll it over the ID. Or, you'd put a very accurate encoder on the platter and pulse the pattern in every X number of degrees. No idea what the pitch of the pattern is or what method they used to record it. Since they did so many, it had to be fairly fast and efficient.
 
ConradH said:
No idea what the pitch of the pattern is or what method they used to record it
Click to expand...
I imagine a circular magnetic head same diameter of the magnetic ring, little less obviously, put the platter upon press a button et voilà. Is a static process, the coil was same axis of the platter.
 
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