Beomaster 6000 (Type 2251) – Standby Running Warm

[Ary]

Hello fellow BeoWorlders,

I’ve got a bit of a puzzle with my Beomaster 6000 (Type 2251). It has been running flawlessly ever since I recapped it with high-quality capacitors from Danish Sound Parts (formerly Beoparts). However, I recently noticed that it’s running noticeably warm in standby, which it never did before, at least not in a way that I would notice. Its not hot hot but like 36 degrees C. when its running it gets hot but I can hold my hand on it for a long time without burning myself.

The trimpots on the amp board are dialed in to service manual specs, so I’m wondering what could be drawing current unexpectedly. Before I dive in and tear everything apart, I’d love to hear some thoughts from you all.

I’ve attached a picture of the relay next to the transformer. It clicks on and off as expected, but there’s some suspicious white residue inside—anyone know if that’s normal or a red flag?

And I noticed that R12 (R1 and 12 are confusingly close together) gets  hot like hot hot like auwy finger hot…. hm?

Appreciate any insights!

Cheers,

Ary

[Dillen]

If the relay contacts have welded, the amplifier section will be powered at all times.
I suggest you check if you have power to the amp section (f.e. by checking if idle currents are present in standby).
If you do, replace the relay.

Martin

[Ary]

Hi Martin

Thanks for your reply—I know you must be busy, so I appreciate it!

I can confirm that the power amp section is completely off, with no current flowing through, and the cooling fins remain cold. I also checked the fuse for continuity, and it’s working fine, so the issue must be elsewhere on another PCB.

Looking at the schematics, R12 appears to be linked to 6R11, a trimmer on the standby PCB, which seems to adjust something on the radio board (PCB8, if I’m not mistaken). Maybe you or someone else here can shed some light on this, as while I’m experienced with electronics, vintage radio circuitry is admittedly not my strong suit!

I also checked whether the radio works, but it doesn’t—I can’t seem to get any tuning. If I remember correctly, Martin, you still sell a part that can restore this functionality? That said, I’m not particularly interested in using the radio, but if fixing it is necessary to resolve the issue, then so be it.

Wishing everyone a great evening—or Friday, depending on when you read this!

Ary

[Ary]

Alright, so I’ve been testing the Beomaster.

The unit seems to function properly overall (aside from the radio board and the blown bulbs for the radio signal on the display board). Disconnecting PCB 8 doesn’t affect the following measurements at all.

I’ve gone through the power supply  and attached the schematic with the voltages I measured. It closely resembles an old post by Sonavor, which I’ve linked here: https://archivedforum.beoworld.org/forums/t/42628.aspx?PageIndex=5

Before I remove the power supply to test components out of circuit, I wanted to ask—has anyone encountered this issue before or have any pointers on where to focus?

I adjusted the trimmer R4 to get a 6.5V output, which lowers the voltage at the base of TR1. This significantly reduces the heat buildup, but I’m sure this is a symptom of a deeper issue. ive also adjusted and replaced all trimmers on the PCB 6 board.

Any thoughts? Would love to hear any insights before diving in further!

Cheers,

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[Ary]

ive noticed also that if the amp has been in standby for a while and i take it out there is a big discharge of something audible though the speakers. Possibly another hint to the problem above perhaps.

[Author]

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