Home Forums Product Discussion & Questions BeoMaster Beomaster 1900 – No sound in left channel on phono/tape input

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  • #50033
    ChrWorm
    BRONZE Member

    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

     

     

     

    #50034
    ChrWorm
    BRONZE Member

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

    #50035
    mexking
    BRONZE Member

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

    Location: Mexico city
    #50036
    Mark-sf
    BRONZE Member

    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.

    #50037
    ChrWorm
    BRONZE Member

    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

    #50038
    Dillen
    Moderator

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

    Martin

    #50039
    ChrWorm
    BRONZE Member

    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?

    #50040
    Dillen
    Moderator

    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

    #50041
    ChrWorm
    BRONZE Member

    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?

    #50042
    ChrWorm
    BRONZE Member

    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!

    #50043
    mexking
    BRONZE Member

    Good job congrats

    Location: Mexico city
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