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Melted circuit board - can it be saved?

Discussion in 'Amp Central Station' started by boomland2, Nov 1, 2018.

  1. boomland2

    boomland2 NEW MEMBER!

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    Hello everyone,

    I picked up a Fender 100SB bass head from a second hand shop who told me it was working perfectly and had been tested. I took it home to use with the intention of using it as a guitar amp (classic Bassman style), and it sounded awful compared to my other smaller bass setup. Hardly any treble on tap, the mids and frequency knobs didn't work at all and with the gain turned up it started cutting out then fading back in. I opened it up and this is what I found on the circuit board, around the gain pot end. Not knowing much about amps, I'm worried as to what it even is, and if it's fixable. Any suggestions?
     

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  2. 8barlouie

    8barlouie Friend of Leo's Gold Supporter

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    Please take this with a grain of salt, but how could you have taken the word of a second hand shop owner without trying it out or at least getting a written return policy? Unless you bought it for a pittance, take it back.
     
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  3. dsutton24

    dsutton24 Doctor of Teleocity Ad Free Member

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    A picture like that doesn't give us enough information to give you a meaningful answer. It's possible that someone will come along who is familiar enough with the amp to know what's going on there, but I think it's unlikely.

    What you probably will get is a bunch of people telling you how awful solid state amps are to work on. They're really not bad to work on, the challenge is to find someone who actually repairs the things.

    Anything is repairable, it's just a matter of whether or not it makes economic sense.
     
  4. BryMelvin

    BryMelvin Friend of Leo's

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    what's damaged on the other side.

    I've fixed ones looking worse with jumpers, but need to find the cause too.
     
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  5. 2 Headed Goat

    2 Headed Goat Friend of Leo's

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    What Bry said... sort out what's made a mess of the board... once that's suss'd go from there. To my eyes it doesn't look melted just messy... clean it up and repair/jumper the damaged traces... the large one on the bottom of the pic is cracked.
     
  6. BryMelvin

    BryMelvin Friend of Leo's

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    Is that a crack or glue dripped accross? I can't tell in pic.
     
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  7. Milspec

    Milspec Poster Extraordinaire

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    Like the others noted, I would have to see the other side to know what the situation was. I have seen much worse as well and been able to clean it up with success, but you really need to investigate the flip side.
     
  8. stratclub

    stratclub Tele-Meister

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    Why didn't you try it out before you bought it? Usually when a circuit board amps malfunctions it needs to be thrown in the dumpster because of how difficult they are to repair.

    Of course the seller knew this and was probably overjoyed that he found a sucker that didn't try it out and believed his lies about it working properly.

    Don't expect any relief from the seller. He will claim that it worked fine when sold and will blame you for damaging it.

    Circuit board equipment sometimes can be repaired, but usually it is a difficult and time consuming project.
     
  9. Papa Joe

    Papa Joe Friend of Leo's Silver Supporter

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    caveat emptor
     
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  10. Wally

    Wally Telefied Ad Free Member

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    And....that is NOT going to yield a ‘classic Bassman style’ audio at any rate.
    The board needs to be cleaned up and dealt with by someone with experience, I would think. But....a dry toothbrush along with a vacuum to suck up the dust will brush away some of that. Check the traces for continuity with an ohmmeter. Check the components and the traces with a magnifying glass. You may or may not be able to check components while they are in circuit.
    Clean and lube and tighten all pots, jacks, switches.

    The only horse whose teeth one doesn’t need to check is the one that someone is giving away. Buyer beware, indeed.
     
  11. radiocaster

    radiocaster Poster Extraordinaire

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    The solder on the pc board? It looks bad but could probably be cleaned up, even if it takes sandpaper, although I would try wiping then a solder sucker, with sanding as a last thing.

    I could be wrong, but a search on that model leads to no results. I'm thinking it's a fake Fender amp with a Fender logo put on it.
     
  12. Bluey

    Bluey Tele-Meister

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    Looks like someones left a bag of coke in there too long.
     
  13. RLee77

    RLee77 Friend of Leo's

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    We need better lighting on that to help see what that mess is; it’s too dark to tell if it’s scorched or if it’s just a mess of too much flux and bad soldering. Does it smell burned?
    Acetone and Q-tips will clean it up so you (and we) can see what’s under all that gunk. We also need to know the component(s) on the other side. Then a schematic will be useful.
     
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  14. BobbyZ

    BobbyZ Doctor of Teleocity

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    When someone says something used has been "tested" it means it kinda sorta does whatever it is it's supposed to do. Probably the pilot light came on when they plugged it in, pilot lights supposed to come on, it tests good.
    "Tested", "checked out by a tech", "clean bill-O-health". . . . . Are really just totally meaningless phrase people use that don't mean Jack Chit about the actual condition.
    Is the seller here trying to screw people? Probably not. Maybe he did plug in an instrument and sound came out the speaker. To most folks that means it's working just fine. Most folks don't know the difference between a good amp and a sick one, it makes things louder, it's working .
     
  15. RLee77

    RLee77 Friend of Leo's

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    It depends on the type of components used, who’s doing the repairing, and how much the amp is worth to begin with. If it’s just normal (not micro surface mount) type parts, repairing pcb quipment can be simple; in some cases, easier than a messy hand-wired circuit. It can’t really be generalized to “circuit board amps” as far as how repairable an amp is; there are a lot of factors.
     
    Last edited: Nov 2, 2018
  16. Tonetele

    Tonetele Poster Extraordinaire

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    If solder has dripped, been melted to parts I'd have to say it is very delicate work ( and costly) for a good technician to repair a pcb. Even then I don't think anyone would guarantee it.
    If you knew the specific circuit replacing it might be the way to go . I used to teach electronics.JMHO
     
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  17. Axis29

    Axis29 Poster Extraordinaire Ad Free Member

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    Can you take it back?
     
  18. jimilee

    jimilee Tele-Afflicted Silver Supporter

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    Point to point jumpers are your best bet.
     
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