Reply To: Beogram 4000 Restoration Issue

#10688
Dillen
Moderator
  • Topics Started 2
  • Total Posts 162

(Thermistor or current limiter…)
Modifying only to compensate afterwards would make little sense in my opinion.

Sorry to say it, but I would suggest replacing that lot of capacitors with single cans of good general purpose types.
I would fit can-types rather than PCB-mounts, exactly as B&O chose to do it. They have
a much nicer “oompfh” for this combination of motors, relays, solenoid and (at times sensitive to clean voltage) electronics.
This goes for the DC-motor versions as well.

And remember – no low-ESR capacitors in any power supply filtering positions in the classic B&Os.

Also make sure to find a bipolar cap with healthy ripple current specs.
Phasing a motor is hard work for a capacitor.

Mains has no reference inside the Beogram.
Chassis ground has no connection to any mains (it would potentially be lethal).
Mains go through the voltage selector and the fuses to the transformer.
Chassis ground is capacitively coupled to signal/electronics ground. If your deck has a three-prong mains plug, the chassis will be connected to the earth pin of the plug.
This means, that you can’t use chassis ground as reference for anything, really – not
for measuring around in the electronics either. Here you must use signal ground for reference.
For convenience I like to clip the meters negative pin to the common negative point of the large cans in the regulator circuit (after your modification no longer accessible in your Beogram).

Martin

  • This reply was modified 1 month ago by Dillen.
  • This reply was modified 1 month ago by Dillen.