Beogram 4000 pop noise when lowering the arm

[Inigo71]

Hi Everyone.

I am refurbishing my Beogram 4000 and I noticed that when lowering the arm a loud pop noise can be heard through the speakers. I suspect that it has to do with the arm big coil, but I changed the 6C1 capacitor and the 6D1 diode, but the noise is still there.

Is it normal, is there something I can do?

Thanks for your replies

[Die_Bogener]

I think the BG4000 had a muting system.

The muting system closes the loop to ground, so there is no noise.

When the needle plays, the loop is opened and there should be sound.

So it looks like a wrong DC level on the sound channels…

[Inigo71]

I thought about that, but apparently the sound of the needle is muted until the needle set on the surface, but the pop noise happens before.

I found that the noise is very erratic some times happens some times not.

Thanks for your answer

[Mark-sf]

I would still suspect the muting contacts. They should be cleaned and adjusted as per the service manual available at https://beomanuals.com/manuals/Beogram/Beogram%204000/Beogram_4000-Service_Manual.pdf.

[Author]

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