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Old 17th Jan 2020, 1:40 am   #1
martin.m
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Default Garrard SP25 motor troubles

I have had an SP25 Mk4 packed away for about ten years. After cleaning the usual hardened grease and re-lubricating, I switched on and noticed a metal to metal scraping noise coming from the motor. On further inspection, a metal disc which had been bonded to the top of the rotor had come loose. One side of the disc appears to be a magnet and the other side has been partially drilled in a couple of places as if to balance it. As an experiment I stuck it back onto the rotor with some UHU solvent based glue (superglue is a little final). On reassembly the deck seems to work fine. Has anyone come across this problem before and what is the purpose of the disc. I thought AC motors didn't need magnets.
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Last edited by martin.m; 17th Jan 2020 at 1:41 am. Reason: Grammar
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Old 17th Jan 2020, 2:47 am   #2
teetoon
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Default Re: Garrard SP25 motor troubles

Hi Martin. This was a very common problem with the MK IV's that were fitted with a synchronous motor.
I did read there was a problem with the glue used.
The dodge is to try and see the pattern of the original glue on the disc and try to line it up as best you can.
I have used araldite to sort it and they never gave a problem after that.
It's difficult to tell if they are noisier after because of the slight mis alignment but for most purposes it's fine.

David.
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Old 17th Jan 2020, 1:56 pm   #3
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Default Re: Garrard SP25 motor troubles

I don't know the point of the disc either but it's a common problem - I've fixed loads like this! Just make sure its as concentric as you can and, as David says, try and line up the glue pattern to get the orientation as close to original as possible, and it'll be fine.
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Old 17th Jan 2020, 2:08 pm   #4
Nickthedentist
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Default Re: Garrard SP25 motor troubles

Thirded. Every one I've seen - even back in the late 1980s when I first picked one up at a jumble sale - has had this problem.

Anyone know what the disc actually does? It looks as if it's made of something similar to ferrite rods.

N.

Last edited by Nickthedentist; 17th Jan 2020 at 2:23 pm.
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Old 17th Jan 2020, 11:04 pm   #5
martin.m
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Default Re: Garrard SP25 motor troubles

Thank you for your replies. I didn't think of looking at the glue pattern first. Too late now but it seems to work OK. The deck is used in my loft room for playing 78s so doesn't need to be studio quality. I wondered what the disc was for too.
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Old 18th Jan 2020, 9:09 am   #6
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Default Re: Garrard SP25 motor troubles

I believe the disc is for balancing the rotor, hence the drilled holes, so it is important to line it up as best you can. I may be wrong......
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