My Rega Planar 3 turntable is belt driven. It has been a year in storage, and now the platter spins backwards. A Google search suggests that one of the motor capacitors is to blame.
I reckon I'll replace both, as the turntable is over 20 years old. But since this is a 220 V circuit, I don't feel comfortable basing my actions on assumptions, hence this question.
Here is a picture of the PCB that drives the motor.
The PCB is driving a "PREMOTEC 9904 111 31813" 50Hz 110V synchronous motor, even though the turntable is rated for a 50Hz 220V line. (Am I looking at a capacitive dropper?)
These two caps are the only components on the PCB (Update: I also found a 1MΩ bleeder resistor hiding under the Rifa). In addition, there's the motor, and a mains switch, and that's the whole circuit.
Here is a picture of the traces:
And here is the whole compartment. The white wires go to the mains switch.
An attempt at a schematic:
simulate this circuit – Schematic created using CircuitLab
First, to get the yellow capacitor (C1) out of the way:
It is a Rifa that hasn't gone boom yet.
- The top is marked 220n X2
- One side (visible in the picture) is marked 275 V ~ SH
- The other side is marked RIFA / PME 271 M / 40/100/56/B / 250VAC / K5
I suppose I can replace this one with any 220nF X2 class 275V rated mains filter cap, am I right?
The white one (C2) is harder.
- The top is marked 220n K J0 (OR JO?)
- One side (visible in the picture) is marked EVOX / MMK / 400-
- The other side is blank.
So my main question is: What type of capacitor is this? Or rather; What type of capacitor is it safe to replace this one with?
Best Answer
MMK is a metallized polyester film capacitor.
220n is 220 nanofarads.
K is 10% tolerance.
It is rated for 400V.