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Just posting this separate from my Beogram 4000 restoration thread as its driving me mad.
I have replaced the motor capacitors and all the power supply capacitors in the Beogram.
When the AC platter motor is running I get this weird noise on the scope trace (measuring the AC drive signal between 0C6 & 0C7). It also infects the 6v supply rail as well.
If I disconnect the motor from the power amplifier (so it doesn't run) the noise goes away.
Any thoughts folks?
Cheers
Paul
What type of capacitor did you fit for the motor phase bipolar?Did you adjust the motor phase as shown in the servicemanual?
Martin
Hi Martin,
I used 2 x 330uf bipolar capacitors in series. I adjusted the motor voltage like it says in the manual but I didn't see anything about phase??
A bipolar capacitor is two discrete capacitors in series with reverse polarity.Fitting two bipolar caps in series would in effect be connecting four discrete caps in series with polarities everywhere and nowhere, and that could give problems.
Do you have the platter and belt fitted? You cannot adjust the motor correctly if it runs alone.
I have tried my old B&O bipolar, a single 330uf bipolar and a bipolar I made out of 2 electrolytics back to back. Non of these make any difference to the noise. I adjusted the motor voltage with the platter and belt on.