Marshall Valvestate 8080 won't turn on at all...

Discussion in 'Marshall Amps' started by steverez, Nov 4, 2009.

  1. steverez

    steverez New Member

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    I have a valvestate 8080 that doesn't turn on. I pulled a bonehead move when I (this is / was my setup) - Guitar plugged into Wah then Overdrive then Distortion and then a Boss DD2-Delay with 2 outputs, one for "direct out" which went to a Peavey Deuce and then the "out" to the Valvestate 8080). It worked for a bit until I used the delay a couple of times. It then went dead and that's it. No lights / power etc. Tried different power cable and verified well known working wall plug. I'm new to amps but I'm assuming that the fuse would be the first thing to look for from what I've seen on the posts. What would be the next step or two if the fuse is ok?
     
  2. Wilder Amplification

    Wilder Amplification New Member

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    By running from the "out" of the Peavey Deuce, are you referring to the speaker out? If so...one can only imagine the world of hurt your 8080 endured. In that case, step 2 would be to take it to a tech.
     
  3. steverez

    steverez New Member

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    Hi,

    Nope, the last pedal in the chain was my Boss Delay. The delay has 2 outputs.

    One output is a "direct out" which went to the peavey deuce. There would be no "delay" effect on the Peavey amp. It's a clean signal.

    The other output is just "out" which would give you the delay effect. That was plugged directly into the Marshall.

    So, 1 delay pedal, 2 outputs. 2 seperate cords, 2 amps.

    Thanks
     
  4. Grandturk

    Grandturk New Member

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    It doesn't seem like that would blow up your amp. All you did was plug in some pedals.
     
  5. steverez

    steverez New Member

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    Any idea what could've happened? I believe the amp has 1 tube / valve. Is there a fuse in these amps? Does it look like a regular fuse? Any help would be appreciated.
     
  6. Wilder Amplification

    Wilder Amplification New Member

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    The Deuce is a "reverse hybrid" amp, meaning it has a solid state preamp section with a valve power amp section. There should be 4 valves in it.

    In regards to your 8080, its failure was more than likely coincidental and had nothing to do with the way you hooked up your pedals. If you check the fuse and it's not blown, you're better off taking it to a tech since these are a solid state hybrid and are a bit more complex than a valve amp.
     
  7. steverez

    steverez New Member

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    Thanks guys. Yep, the Deuce has 4 valves. Can't miss that glowing orangey-yellow. I'm going to check the fuse tonight. I don't mean to sound like a total newb, but does the fuse look like a typical fuse? I mean cylindrical shaped glass with filaments? Thanks again.
     
  8. Wilder Amplification

    Wilder Amplification New Member

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    Yeah...it may or may not be glass. Some are ceramic and you can't see through them. On those you'll have to test them with a meter.

    Now if it's a glass one and the inside of the glass looks smoked, that mean's something is seriously wrong and it needs to go to a tech for further troubleshooting.
     
  9. steverez

    steverez New Member

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    All four fuses I tried blew.
    1st time powering on the power button was accidentally on when plugging into outlet.
    2nd time when turning power on correctly.
    3rd time when I turned it on after I pulled the valve / tube (which I'm thinking I probably shouldn't). The fuse then glowed a very bright nuclear green and blew.
    4th time when I put the valve / tube back in. It still had the nuclear green flash. It didn't the first time before when the valve / tube was never removed.

    Thoughts?

    Thanks,
     
  10. Wilder Amplification

    Wilder Amplification New Member

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    Is it the HT fuse that blew, or the mains fuse?

    Was the amp in standby mode when powering up?

    If it was the mains fuse and the answer to question number two is "yes", then it sounds to me like you may have a fried power transformer.
     
  11. steverez

    steverez New Member

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    It Was the 2 amp 250 volt, little glass fuse located near where the power cord plugs into if that helps. There isn't a standby mode. There's just on and off. Could the valve be the problem or no because it still blew without the valve / tube being plugged in?
     
  12. Wilder Amplification

    Wilder Amplification New Member

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    Whoops...I was thinkin' about the Deuce for some reason. Long day lol.

    In that case it's the mains fuse. Power amp or power supply issue...nothing else you can do but take it to a tech.
     
  13. steverez

    steverez New Member

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    Thanks, I think I'll be calling tomorrow. I'll let you know what it was.
     
  14. steverez

    steverez New Member

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    I just talked to the amp guy and he states (over the phone) that the output is most likely blown. I google quite a bit and can't really get a straight / lamen's answer on the exact location and how to fix it myself. I can solder and feel fine removing / replacing components. How should I attack this?

    Thanks,
     
  15. Wilder Amplification

    Wilder Amplification New Member

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    You should attack it by taking it to a tech.

    Solid state amps...even the ones with the DMOS chips, are quite complex and not for the novice to try to repair. There are other parts that the chip could've fried along with it and with no knowledge of electronics theory and how to read a schematic, you have no idea where to look for what parts it could've possibly taken with it.

    Since solid state amps take random parts with them when they fry, I can't even begin to tell you where to look without having the amp in front of me and testing all the parts to find out what's blown. When solid state amps blow, the parts that fry as a result are random, which is why you can't find a straight answer on what to check simply because there is no straight answer due to the random parts that fry. There may even be tracings on the board itself that have melted off of the board that will require minor surgery to repair. You're much better off taking it to someone with experience in solid state amplifiers.
     
  16. steverez

    steverez New Member

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    Thanks for the advice. I've taken my amps to him in the past so it looks like I'm heading there again. I'll let you know what the damage is / was.
     

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