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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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4th Dec 2019, 11:32 am | #1 |
Dekatron
Join Date: Apr 2005
Location: North Wales, UK.
Posts: 6,884
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Sony turntable motor weak
Hi
I'm renovating an oldish Sony music centre (HP211) and the turntable motor is not strong enough. It works from a tap on the mains transformer. No voltage is given in the manual, but it's around 140v which I think is OK. It spins freely and the coils haven't overheated. However it struggles to turn the platter and when it finally gets up to speed 33rpm records play perfectly - at the 45rpm setting! It can be easily stopped by hand. Besides lubrication is there anything else I can do? It's a simple AC induction motor. |
4th Dec 2019, 12:06 pm | #2 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,820
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Re: Sony turntable motor weak
Puzzling!
Do we know for sure that this definitely worked once? First thoughts are that possibly the wrong motor has been fitted, i.e. one that's designed to run directly from the UK mains. |
4th Dec 2019, 12:24 pm | #3 |
Rest in Peace
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,306
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Re: Sony turntable motor weak
As a U.K spec motor would be under - voltaged by at least 39&, your theory sounds right, Nick. Having said that, I'd be reluctant to run it from a higher voltage, unless there was any way I could confirm that it was indeed a 230/240v motor.
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4th Dec 2019, 1:00 pm | #4 |
Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
Posts: 3,315
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Re: Sony turntable motor weak
It appears to be a 110 volt motor with an idler drive to the turntable. Have you cleaned the drive and turntable rim?
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4th Dec 2019, 3:56 pm | #5 |
Hexode
Join Date: Feb 2007
Location: Chesterfield, Derbyshire, UK.
Posts: 481
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Re: Sony turntable motor weak
Without seeing a diagram I assume it's a standard shaded pole motor? It's not a capacitor run motor is it?
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4th Dec 2019, 4:07 pm | #6 |
Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
Posts: 3,315
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Re: Sony turntable motor weak
From the circuit diagram I saw on the internet the motor is not shown - just the connection from the transformer showing a separate 110 volt winding going to a socket marked motor.
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4th Dec 2019, 4:20 pm | #7 |
Hexode
Join Date: Feb 2007
Location: Chesterfield, Derbyshire, UK.
Posts: 481
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Re: Sony turntable motor weak
I saw that, The record deck TTS-312 is a separate service manual.
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4th Dec 2019, 10:04 pm | #8 |
Dekatron
Join Date: Apr 2005
Location: North Wales, UK.
Posts: 6,884
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Re: Sony turntable motor weak
Hi
Thanks for your ideas. It's a standard shaded pole motor, no run caps or anything like that. It runs OK on its own but is easy to stop by hand. I wouldn't say the unit's been apart before and everything's original and typically Sony of the period. The platter's quite heavy, but there's no question of the idler slipping; the motor just stalls. I vaguely remember the Grundig TK120 series of tape recorders having a lazy motor, but lubricating and running it brought it back to life. As Nick says, puzzling! |