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Marshall valvestate 8040 No Power?

VaiaiVaiai Frets: 530
in Amps
Mates amp is completely dead - no power light - all cables and fuses checked - any ideas?
Any common issues they have? Asked him if he has checked the amp fuses too - not just plug.
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Comments

  • DJH83004DJH83004 Frets: 196
    There is an internal PCB mounted fuse on the 8040 from memory about 500mA, you will need to take the chassis out to inspect it. The power on LED is supplied after the bridge rectifier, so if everything is dead check the fuse first, then likely suspects are mains transformer or bridge rectifier. 
    www.classicvalveamps.co.uk Nottinghamshire
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  • DJH83004DJH83004 Frets: 196
    Forgot to mention, If it is the fuse and it continues to blow it may be the valve or more likely the TDA1514 chip, which really is time to take it to your local amp tech. 
    www.classicvalveamps.co.uk Nottinghamshire
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  • VoxmanVoxman Frets: 4724
    I dont know if its the same on Valvestates but the internal fuse went in my dsl401. @ICBM described it as a nuisance fuse that was under strain slightly at power up and would go a little over the stock fuse rating, and that it was perfectly safe to go up from I think 6.3mA to 10mA which should prevent future problems.
    I started out with nothing..... but I've still got most of it left (Seasick Steve)
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  • ICBMICBM Frets: 72407
    Voxman said:
    I dont know if its the same on Valvestates but the internal fuse went in my dsl401. @ICBM described it as a nuisance fuse that was under strain slightly at power up and would go a little over the stock fuse rating, and that it was perfectly safe to go up from I think 6.3mA to 10mA which should prevent future problems.
    Not applicable here. That's a valve filament fuse - T6.3A.

    There is only one fuse in a 8040, the mains primary fuse which is T500mA as DJH said. This isn't prone to nuisance blowing but could possibly have failed due to a power spike or just old age. If it has, replace it with the same value. If it blows again, take the amp to a tech.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein

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  • DJH83004DJH83004 Frets: 196
    Yes. take it to an amp tech - but not me :)  don't mean to be flippant but had my fill of changing TDA chips, ICBM on the other hand loves them to bits  ;)

    www.classicvalveamps.co.uk Nottinghamshire
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  • ICBMICBM Frets: 72407
    DJH83004 said:
    Yes. take it to an amp tech - but not me :)  don't mean to be flippant but had my fill of changing TDA chips, ICBM on the other hand loves them to bits  ;)
    Vaiai is in Scotland too, I can't wait! :)

    Actually I don't mind really - there are worse jobs. Hopefully it's not that anyway though - it's probably the most expensive fault on these. I've never seen one with a blown PT.

    Check the fuse first, and if it's not that feel free to get in touch.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein

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