Marshall Valvestate 8100 no sound at all

Discussion in 'General Electronics Chat' started by john_guitar, Dec 24, 2011.

  1. john_guitar

    Thread Starter New Member

    Dec 24, 2011
    4
    0
    Greetings,

    A have a Marshall Valvestate 8100 and it is producing no sound at all and the tube does not glare at all. I assume there is an issue in the power supply.
    (Because, the heater for the tube takes power before the rectifier and the zener diodes, is that correct? )

    Furthermore, I attached a multimeter to measure AC voltage at the Secondary of the power transformer and I got 0V. I attached the ground of the multimeter
    to the 2nd White wire and the RED at the 1st White wire. It must show me about 30V AC, is that correct? Instead it shows me 0V.

    When I attach the multimeter at the Primary wires it shows me 220VAC, that is correct.

    Any response will be highly appreciated.


    Thanks in advance
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    Do you have the schematic?
    I have one attached.

    What is the condition of R112 and R113?
    Those should be 180 Ohms/ 7 Watt.

    Bertus
     
  3. MrChips

    Moderator

    Oct 2, 2009
    12,418
    3,355
    Did you check the mains fuse?
    Are there any panel lights that are supposed to turn on?
     
  4. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    Please post a schematic of your amplifier, if you can possibly get one. Anyone who has not dealt with this particular model of amplifier or a closely related one will otherwise be unable to give detailed advice.

    What you describe could point to a failed power transformer, or possibly a blown fuse, a damaged switch or many other issues.
     
  5. sheldons

    Active Member

    Oct 26, 2011
    616
    101
    check the on off switch first-both sides-if thats ok disconnect the transformer from the board(the secondary wires)and check the ac supply from the secondary side of the transformer-if its present check the dc supply for faults-if not then you have narrowed the fault down to a faulty transformer or oc fuse or switch(or mains cable) if still in trouble we shall assist you more.
     
    Last edited: Dec 25, 2011
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