Problems with a Beogram 4004

[Guillaume Gonzalez]

Hello everyone

Sorry for my poor english (google trad)

I recently acquired a Beogram 4004 turntable, which is having some issues.

Until now, I was using a Beogram 2402 with a Beomaster 2400-2 amplifier, and the setup worked perfectly.

I had the opportunity to buy a 4004 for a reasonable price and would like to use it. Unfortunately, no sound is reaching the amplifier; I only hear the sound of the stylus rubbing against the record.

I don’t have extensive electronics knowledge but have been searching forums for several days without success.

I tested the 7-DIN cable, which seems fine, and also checked the mute board, but without success.

If any of you have encountered the same problem, I would appreciate any information.

Thank you

[Mark-sf]

Do you hear the click of the muting relay after the arm sets down? Have you tried using the cartridge from your 2402?

[Guillaume Gonzalez]

Hi

Thanks for your replies.

I tested it with the 2402 cartridge.

I also tested the relay and can hear it clicking.

However, I didn’t notice if it clicks when the tonearm sets down.

I’ll test it tomorrow and let you know.

Thanks

[Guillaume Gonzalez]

Hi,

I think you’ve found the source of the problem.

The relay doesn’t click when the arm sets down.

I tested it by powering it directly and it clicks correctly, so I think there’s a power supply issue on the PCB 8 board.

Any idea what I should test?

Thanks

[Mark-sf]

I would check the voltages on the muting relay board. You should have 21V DC on P1 of the P8 Connector and .7V when the tonearm drops to open the muting relay. You also might try cleaning and adjusting the muting relay delay trimmer, 8R2.

• This reply was modified 1 week, 2 days ago by Mark-sf.

[Guillaume Gonzalez]

Okay, thank you very much.

I’ll test all of that.

[Guillaume Gonzalez]

I finally managed to take the measurements
According to this picture

Tonearm raised, I get

• 1 -> 30.7 V CC*
• 2 -> 21.7 V CC
• 9 -> 0.7 V CC

Tonearm sets down, I get

• 1 -> 28.8 V CC*
• 2 -> 21.7 V CC
• 9 -> 15 V CC

I also played with TR2 and I don’t get the impression that it has any effect on the circuit.

Can I try powering the relay with an external battery when the turntable is on?

Thank you for the time you are dedicating to my problem.

• This reply was modified 1 week, 5 days ago by Guillaume Gonzalez.

Attachments:

You must be logged in to view attached files.

[Mark-sf]

It’s actually Pin 1 that is biasing 8IC1 to turn on and close the relay. You are getting the correct input voltage so I would look at the trimmer 8R2, 100mf cap, 8C1 and diode 8D2.

• This reply was modified 1 week, 2 days ago by Mark-sf.

[Guillaume Gonzalez]

Thank you again so much for your help.

I’m going to change the 100mf cap because it looks worn out.

[Guillaume Gonzalez]

It seems that 8d2 is fried.

I’m going to replace both of them, we’ll see.

[Author]

Posts