Beogram 6000- restore and fix ground issue

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  • #7329
    ccamargo
    BRONZE Member
    • Topics Started 1
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    Hi

    i am new to the forum, I have been reading the different topics without luck on finding the issue I have, so decided to open this topic, thanks in advance for your support.

    I got a Beogram 6000 from a neighbor who did not have the time a patience to try to fixed it. It is in fare condition I must say, but I notice different hands try to make it work with no luck. Anyway, at first I saw the bulb on the detector arm was not working, easy fix, follow the circuitry and found the zener diode  ID09 broken, replaced it along with the  TR10 transistor and voila, detection of LP works again, disc are detected and the arm lower properly.
    I also replace main electrolytic capacitors, filter C1, C2, C3 at the motor and the bipolar C4 along with C13 to C16.
    Now, the big issue I have is that after some time playing music, the transformer gets really hot and the fuses blown. From the beginning I found weird, and still, that the chasis is not connected to the negative part of the circuit. Inspecting the schematics, the only clear physical-electrical  connection to the chasis is through 47nF capacitor to the shield of the cable that goes to the amplifier. Am I missing something here? How I am suppose to measure voltages and signals to chasis when clearly there is no electrical connection between them! That puzzles me, and I am not sure this has connection with the overheating of the transformer, I believe so, but I cannot find anywhere in the service manual other electrical connection to chasis. I would really appreciate your advise and comments, time being I will start replacing old capacitors. I suspect of the solenoid circuit that is draining too much current, but at first seems to be ok…

    thansk Christian

    #7331
    Dillen
    Moderator
    • Topics Started 1
    • Total Posts 35

    Hi i am new to the forum, I have been reading the different topics without luck on finding the issue I have, so decided to open this topic, thanks in advance for your support. I got a Beogram 6000 from a neighbor who did not have the time a patience to try to fixed it. It is in fare condition I must say, but I notice different hands try to make it work with no luck. Anyway, at first I saw the bulb on the detector arm was not working, easy fix, follow the circuitry and found the zener diode ID09 broken, replaced it along with the TR10 transistor and voila, detection of LP works again, disc are detected and the arm lower properly. I also replace main electrolytic capacitors, filter C1, C2, C3 at the motor and the bipolar C4 along with C13 to C16. Now, the big issue I have is that after some time playing music, the transformer gets really hot and the fuses blown. From the beginning I found weird, and still, that the chasis is not connected to the negative part of the circuit. Inspecting the schematics, the only clear physical-electrical connection to the chasis is through 47nF capacitor to the shield of the cable that goes to the amplifier. Am I missing something here? How I am suppose to measure voltages and signals to chasis when clearly there is no electrical connection between them! That puzzles me, and I am not sure this has connection with the overheating of the transformer, I believe so, but I cannot find anywhere in the service manual other electrical connection to chasis. I would really appreciate your advise and comments, time being I will start replacing old capacitors. I suspect of the solenoid circuit that is draining too much current, but at first seems to be ok… thansk Christian

    The chassis is not signal ground.
    Don’t use the chassis as ground reference when measuring.
    The capacitive coupling is correct.

    Apparently something is pulling too much current.
    If the motor phase is set correctly you will have to separate circuits to see, what is pulling a lot of current.

    Martin

    #7332
    ccamargo
    BRONZE Member
    • Topics Started 1
    • Total Posts 2

    Thanks Martin for prompt response.
    indeed no connection between ground and chasis, I just wander why in the service manual explicitly refer to do the measurement to chasis…. Anyway, it is good to get confirmed I do not need to worry about that anymore. As you suggest I will start splitting circuits and check which part is causing the issue, I will report any findings here, any other ideas are welcome.

    Christian

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