View Single Post
  #28   Report Post  
Robert Gault
 
Posts: n/a
Default Thorens Turntable Repair

Len Moskowitz wrote:
Robert Gault wrote:


What voltage, if any, do you read at the motor terminals? Likewise as
you move from the wall mart through the PCB board?



The regulator diodes are overheating, indicating a short somewhere. The
two analog ICs (LM324N and MC34001) are not getting Vcc. I disconnected
the motor (which should be run by 110 VAC anyway) and saw no change (as
expected). I pulled both ICs and saw no change. There's one
small three-terminal device that could be either a voltage regulator or a pass
transistor -- that's the next thing I'll look at.

Anyone know what voltage Thorens runs its analog ICs at?

I'm trying to track down a schematic or service manual for the TD-146.
All leads appreciated.

Make sure that none of the diodes in the full wave bridge have blown.
This is frequently a problem.