[BillWay]

Q Audio in Massachusetts (qaudio.com) sells genuine Thorens belts, which eliminates lots of guessing.

[rcag_ils]

I followed BillWay's Thorens manual, and got all the voltages adjusted to spec, I didn't have to adjust the speed pots, all speeds are dead on.

The phase voltages were not grossly out of adjustment to begin with, they were .4 to .5Vac off.

After the adjustment, the start-up rattling sound's gone, the belt doesn't slip off the pulley, and started up smoothly. But after it got up to speed, the motor's still making that "knocking" noise. The motor's also making the "knocking" noise faintly with the belt off (no load). The pulley wobbles a bit.

So I think the motor shaft's hitting the bearing while it's turning, or the shaft somehow got bent. But I like the smooth start.

[p2chiu]

Thanks folks, looks like bulb value in Thorens 125 speed control board is 6v 20ma ( 0.02a)
 But it is hard to find replacement bulb with exact value. Does anybody know -- is it ok to use 6v replacement bulb with higher ma ( such as 40ma or 80ma). Does higher Amp value of the bulb will affect  the 'resistor' and ' positive temperature' value of the circuit ?
Thanks :

[p2chiu]

Oh, I forgot, manaul said that the bulb uses in thorens 125 speed control board is to stablize the motor speed. The bulb acts as a resistor in the circuit with positive temperature..it uses to stablize the current sending to the driving motor. So I wonder whether 6v bulb with different Amp will affect the resistor and positive temperature value. Any body know ? Thanks

[BillWay]

If no one here knows (and I certainly don't) it might be worth a phone call or email to Q Audio (qaudio.com), who say they service all Thorens models, and carry some Thorens parts for the old stuff. When you do find out, let us know.

WW