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Marshall Valvestate VS100

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  • Marshall Valvestate VS100

    Good evening,
    A while ago I bought a VS100 (head) with an electronic problem. The volume was very very low, and every channel sounded distorted. Also, there was a dead resistor, R20, that every time i changed, it would burn.
    The output transistors had already been changed, wrongly: the two pairs of BDV65 and BDV64 were changed to four TIP142.

    I changed two of them to TIP147 (T11 and T12), and discovered that T10 was shorted, changing it too.
    T8 was dead, so I replaced it and R20 stopped burning. T7 is fine.
    Every 5W resistor was dead (R 19,21,24,25) and when i replaced them, the volume problem was fixed!
    The valve was changed too.


    Now I just have the distortion problem: clean channel is distorted (not too much). Also, when I play more than one string, it looses all sound definition (the sound become "muffed"), whatever the channel.

    Today I replaced T4 and T6 (someone told me they were a common problem in this amp) and every output transistor. The problem is still here.
    Any idea?

    Click image for larger version

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