Reply To: Beogram 4000 Restoration Issue

#10646
Dillen
Moderator
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One thing that kills transformers in these Beograms is rush-in current.
This is an issue particularly if the Beogram stood unused for a long time, and definitely if someone put in low-ESR filter capacitors.
The latter can be seen as an almost dead short right at the moment when voltage is applied, which puts a huge stress on the transfformer (and rectifier etc.).
Always bring a long stored Beogram up slowly on the variac for the first time to save the transformer.

Replacing one filter capacitor with two or more paralleled capacitors will only add to the risk of damaging the transformer as the resulting ESR (impedance) would be very low indeed.
The regulator would also be at risk, because of the reservoir capacitor it replenishes.
I wouldn’t recommend it.

Also, I am not sure what you measuring in the two photos with the multimeter.
Looks like the meter is in DC voltage mode while you measure on the fuses (?). And where is the reference (meter ground) connected?

Martin

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