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Thread: Marshall JCM 900 SLX BR3 Issues

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    Marshall JCM 900 SLX BR3 Issues

    Hi, new to the forum and semi-noob in electronics

    So like many, I had issues with my JCM 900 BR3 Bridge Rectifier, which was dead and burnt some traces
    I changed it (400V instead of 50V) and changed C8; I had to use the diode legs because the traces were burnt
    Powered up with 4 preamp tubes and they all lit up
    Put some power tubes on and now only 2 power tubes light up (V7 & V8 I guess, both further from the preamp tubes)
    None of the 4 preamp tubes light up, nor do the 2 first power amp tubes
    When I turn the amp on, I'm not getting any voltage reading on C8 (I have normal ± 500V reading on the 2 large electrolytic caps)

    Any help is appreciated

    Thanks

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    If two power tubes have filament voltage and the other two and no preamp tubes light, I suspect a connection issue. Probably another burnt or open trace. Follow the traces that carry filament voltage from tube to tube and see where it isn't.

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