Amp won't come off standby

Discussion in 'Amps and Cabs' started by taper420, Sep 5, 2008.

  1. taper420

    taper420 Member

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    Sep 5, 2008
    Well I'm bringing it in cause it's still under warranty, but I thought maybe it's something simple that I'm not thinking about so here's the problem:

    last week my amp blew a tube. at least that's what I thought. there are two lights, one for the standby and one for the power... the power one stayed on... the standby light went out (which is what happens when you put it on standby). I checked the back and sure enough, one of the tubes was out. I just got a matched quad and put them in. I put it on standby to warm em up... after about 10 minutes I switched the standby switch to on... but no green light. All the tubes are lit up in the back. It's not the fuse, because I took that out and nothing lit up, whereas with it in, it acts as if it's on standby (tubes light up, channel lights, pedal switch). So what are my possible culprits?

    amp: peavey 6505+, stock tubes we're Sovtek 6L6GC's, were replaced with Sovtek 6L6WXT+'s

    there's a block diagram at the bottom of the manual
    http://www.peavey.com/assets//litera...s/00575680.pdf

    this is not my amp but it's close, so maybe the relevant circuitry is the same:
    http://www.schematicheaven.com/newam...ey_evh5150.pdf

    i have a 6505+ which is exactly the same as a 5150 II
    that schematic is for a 5150
    The original 5150's (and 6505's) have one less preamp tube (than the 5150 II, and 6505+), and they don't have separate EQ for the channels... that's the only differences I'm aware of
     
  2. apollon

    apollon Member

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    Sep 22, 2006
    Hi

    Have you got it fixed?

    My 5150 did the same just now

    i was playing it cranked when
    it suddenly died :(

    I just bought it yesterday secondhand to


    Best regards Andreas
     
  3. SatelliteAmps

    SatelliteAmps Member

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    I think the pilot is running off the filament supply. Might have toasted the bulb when the tube went.
     
  4. travis_38

    travis_38 Supporting Member

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    same thing happened to my 5150 about 2 years ago... been on the workbench ever since
     
  5. Nolatone Ampworks

    Nolatone Ampworks Silver Supporting Member

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    I dug up a photo of the 6505+. Looks like those things use LED's. I suppose one could have cooked, but that shouldn't keep the amp from going out of standby.

    If your tubes are glowing, that means your filament supply is most likely ok.

    I bet that amp has an HT fuse inside. It's a second fuse that higher power amps usually have for the B+ supply coming out of the rectifier. I bet that fuse is mounted to the PCB inside.

    If you decide to open it up, BEWARE! Those power supply filter caps, ESPECIALLY larger ones that are likely to be used in an amp like this can store enough charge to KILL you if it hits you wrong! If you don't know how to deal with that, I don't recommend opening the amp up.

    If not the fuse, I don't know what all else the is in the guts of that Peavy that could have fried, but when a tube went out, it could well have taken other bits with it.
     
  6. SatelliteAmps

    SatelliteAmps Member

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  7. rockon1

    rockon1 Member

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    Yeah, PV puts lots of fuse protection in thier amps. My JSX had,if memory serves me well, 4 fuses inside. I blew one using a faulty bias probe. Bob
     

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