Reply To: BeoGram 4000 tone arm problem…

#11576
spassmaker
BRONZE Member
  • Topics Started 4
  • Total Posts 61

Hi Graham

Am I right that the tonearm is “tracking” in Play mode?

If the tonearm travels not to the home position there seems to be a error in the motor driver stage.

here to check transistors:

TR 26, 27, 28, 29, for FF and  tracking forward

TR 30, 31, 32, 33 for  FR  and “tracking backwards”

These are the drivers for the motor in “play mode”.

Tracking is activated via 0R3 and =0R4, means if the leavespring contact is not engaged (OPEN) by the solenoid, there is no tracking possible because there is no voltage (around 20 to 24 V) at 0R3 and 0R4.

Hope I’m right, if not let me know:

As I remember, there should be a tracking function in both directions (0R2 and 0R3) so when in “Play” mode try carefully pushing the toneearm to the right direction the tracking motor should  work.

FF and FR is  independent from this leavespring switch, as the arm should travel when you press STOP,  FF or FR while the solenoid is deengaged.

FF and FR is activated by the switches in the pushbuttonboard (BOARD 4) via TR 25 and TR 34 on BOARD 1.

As no return with STOP or FR is possible I would search the mentioned transistors TR 34, 30, 31, 32, 33 for shorts or open.

Had quiet often damaged transistors in the driver stage.

 

Kind regards

Christian