Motor for Systemdek llX

[markinuk]

Hi Watchvet,

It's great news that only the resistor is burnt out !

I'm not able to help much on the specific resistor/ capacitor values, as I only know the UK figures. However, I think the capacitor value is likely to be in the region of 0.18µf, rather than the 0.22µf we are used to in Europe. That's because the motor will be running at 300 rpm, derived from the 60Hz line frequency, instead of the 250 rpm usual in the UK or Europe, where the line frequency is 50 Hz.

I defer to gain-wire on this, as he is based in Canada, though I'm not sure a tape motor is a suitable guide. It depends mainly on the voltage marked on the label at the bottom of the Systemdek's motor, which your tech should look at. If this says 110 volts, as many of these motors do, maybe 3.3 kohms is the correct resistor. If the deck came from our part of the world, it will, of course, have been fitted with a resistor as standard, and 6.8 kohms is the value suggested when connecting to a 230 volt supply.

HTH,

Mark

[gain-wire]

hmm, well thanks for telling me that, I wouldn't have guessed the resistor was there for THAT reason. funny cause I've seen synchronous motors use a series resistor before and those motors were not made to operate on 220V...

you're right on that capacitor thing though. Oh well I guess, go with the 0.18uF then, watchvet!

[watchvet]

Gain-wire, markinuk:

Thanks for the collective information. I'll pass this along to to the tech on Monday.
I'll replace the capacitor and resisitor.
I'll keep you posted.

[PL135]

The resistor in the drive circuit is there to reduce the voltage, which in turn reduces the torque and the amount of motor vibration. This obviously improves the drive to the platter!

The same circuit is used by Naim Audio in the Armageddon PSU for the Linn Sondek LP12. They have a 430VA toroid which drops the 230V to 110V, then feed it through a 3K3 5W resistor and use a 0.22uF 250V Polyester phase capacitor (blue phase), for 230V 50Hz operation.

You will need a 0.18uF 250V Polyester capacitor (blue phase) and 3K3 5W wire wound resistor for the 110V 60Hz mains your turntable is powered from. (without the transformer!) There should be around 85V RMS over the Red phase of the motor when you are done.

Hope this helps

Regards
Peter

[watchvet]

Peter:

You were right on the money with the capacitor and resistor values.
I gave the tech a copy of your post and that's what he ordered. After handing over 50 bucks, I got the turntable back yesterday and I am now sitting here enjoying that wonderful analog music again!

So thanks a million to you in South Africa..... and to markinuk and gain-wire in Ottawa who made suggestions and pointed out it may not have been the motor after all.
This website and all you folks saved me about 600 bucks for a new turntable that I would have needed to get the same quality I have been used to with the Systemdek/Rega 300/Linn K9 combination.
I'll make a donation.

Martin.

[gain-wire]

GOOD, I knew it wasn't the motor! Although I was off about those other things...

[markinuk]

Excellent news! Glad to be of help in some small way.

Mark

[PL135]

Hi Martin

Fantastic news. It was a pleasure to be of some help, enjoy!

Kind Regards
Peter