Linn AC Motor

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Andrew
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#1 Linn AC Motor

Post by Andrew »

My lad has a Linn Basik and it's motor seems to be erratic at best, sometimes it starts running, sometimes not.

I have taken the simple PSU apart and there's clear signs of heat damage on the voltage dropper Linn use to reduce the voltage to the motor and hence lower vibration.

I'll change that for a better quality part.

My immediate thoughts were the caps had gone south as some of them must be acting as motor run caps, shifting the phase etc, but the three caps all measure OK when out of circuit. Could they still be breaking down?

Or, could the motor be failing? If so anyone know where to get one from and how to get the belt drive pulley off the motor's spindle, I can't find any evidence of a grub screw so I am guess it's a press fit?

Thanks.
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Daniel Quinn
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#2 Re: Linn AC Motor

Post by Daniel Quinn »

When my PT export motor/ power supply went , I switched it for a DC maxon motor and a £50 DC power supply .
.

It was so much better .

As an aside I upgraded (sic) to an origin live power supply. What a load of wank it fluctuated with temperature to an alarming degree
Ant
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#3 Re: Linn AC Motor

Post by Ant »

Ive found plenty of caps measuring fine when taken out then breaking down under load when back in use in similar power supplies ive looked at. the linn pulley is a press fit, last one i looked at was an axis which i think is the same motor. Had to make a little tiny puller out of a 25mm cone point setscrew and a piece of aluminium square section. Slot cut out of the bottom to make it a c shape, threaded hole in the opposite side so the box section slipped under the pulley and the cone point setscrew pushed down on the motor spindle to push it out. I had to machine the screw down so that it had a pin end to push the pulley all the way off.
It was a bigger pain in the arse to get the pulley back on.

Id be inclined to change the caps first before attempting to get the pulley off to get inside the motor
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Andrew
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#4 Re: Linn AC Motor

Post by Andrew »

Thanks all,

I must admit to being slightly surprised the caps measured ok, they were my first thought. I'll do the caps and the main dropper resistor and see if it behaves itself on the bench, to be honest, I don't fancy having to remove that pulley!

Andrew
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pre65
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#5 Re: Linn AC Motor

Post by pre65 »

Andrew, if you end up going the DC route I have a Nick G DC power supply he built for turntable use. It has two independently adjustable (internally) outputs for 33/45.

It belongs to Nick, and although I don't use it anymore I seem to be the long term custodian. :lol:

Nick might remember what is inside. :)
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Nick
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#6 Re: Linn AC Motor

Post by Nick »

Three leg regs
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#7 Re: Linn AC Motor

Post by Andrew »

Thanks for the offer Philip, (and Nick), I'll see how far I get with repairing the supply and keeping the deck 'original'.

Andrew
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Nick
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#8 Re: Linn AC Motor

Post by Nick »

Yep at the time I built that supply for the origin live motoro had fitted. There are better driver circuits I didn't know about then.
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