Beomaster 1900 – No sound in left channel on phono/tape input

[ChrWorm]

Hello everybody.

I have a beautiful old Beomaster 1900 paired with two Beovox S45-2 speakers.

I have a problem with the left channel though.

When I press the FM-selector, sound is playing nice and normal from both speakers, and the balance-sliders works well, adjusting from left to right speaker.

When I am using the Phono or the Tape input, all sound disappears from the left channel.

I have an Beogram 1102 and a Beocord 1500, and the problem is the same with both devices.

I have just changed all of the capacitors and the lamps for the indicators, as I have read, that the problem could be with them. But the problem persist…

I have bought the capacitor-kit and lamp-kit from Beoparts.

Any advise on how to proceed?

 

Best Regards

Christian

 

 

 

[ChrWorm]

As a sidenote I should mention that the problem is the same even if I use the output for speaker-set 2.

[mexking]

I would start looking at the phono and tape preamp, Do the FM presets work OK

[Mark-sf]

From the diodes D200, 201, & 202 all three sources share the same circuit. So I would start by checking whether you have a signal on the anodes of D200 (Phono) and D201 (Tape). If not then I would trace back into their respective preamp circuits.

[ChrWorm]

Thanks for the helpful input.

The FM presets work normal, sound coming from both speakers without any distortion.

I will try checking the signal at D200 and D201 as suggested and the preamp circuits.

Thank you in advance

[Dillen]

Was this problem also present before you started work on the Beomaster?

Martin

[ChrWorm]

Yes it has always been an issue, from the very start. It was the reason I changed the capacitors.

And because it have developed the classic humming, so I did an overhaul with a capacitor-set and new bulbs of the correct type?

[Dillen]

A scope to the signal path would reveal the cause in a few minutes.
Lacking a scope you could compare DC voltages on the transistors in the preamp L+R sections.

Martin

[ChrWorm]

I work as an automotive technian, so I have acces to an scoope.

I will begin to troubleshoot over the weekend, and get back when I have some more progress.

 

Thanks for the helpful input so far?

[ChrWorm]

Problem solved! Found som broken traces toward D200 and D201 on the board itself. Made a repair, and now the sound is perfect from both speakers?

Thanks a lot for all the help, fantastic!

[mexking]

Good job congrats

[Author]

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