This is a follow up to my recent post about the redesigned Beogram Commander remote control board, which now works in both (DC-motor) Beogr...
Thursday, May 14, 2015
Beogram 4000: Adjusting the Solenoid and the Switches
Still a few odds and ends to take care of in the Beogram 4000 that I am rebuilding right now. Any complete restoration should include an adjustment of the solenoid and the switches that it controls to specifications. The solenoid not only takes care of the tonearm lifting and lowering, it also actuates three switches that control the audio muting function, the solenoid current (power), and the carriage transport enabling function. The audio muting switches are responsible for grounding the cartridge coils until after the needle has hit the record. The solenoid current limiter is responsible for lowering the current in the solenoid once it is engaged. This prevents the solenoid from overheating while the record is playing and the arm is down for extended periods of time. The carriage transport enable switch enables the servo motor once the arm is down. This prevents accidental carriage motion in case the arm is touched when it is up.
I made a short video that discusses the circuit and shows how to adjust everything to specifications. Enjoy!: