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A question for you tech guys

Discussion in 'Amps and Cabs [BG]' started by AssMan, Jun 16, 2001.


  1. AssMan

    AssMan

    Dec 2, 2000
    Minnesota, USA
    My guitarist lent me his old amp and guitar in exchange for my old amp and bass. He said the amp hadn't been working since one day when he turned it on and heard a loud pop. I figured he just blew a fuse, no big deal. So I took it home opened it up and sure enough, the fuse was fried. So I replaced the fuse, turned it on, and it blew the fuse again. Any ideas on what the problem could be? The amp is a Peavey Studio PRO 50 (SS), and the fuse is a 2 Amp 250 volt fast blow.
     
  2. do you have any idea how much things can cause a shortcut ? woah.. just open the amp, and take a good look at the circuit-board.
    I know it sounds strange at first, but take a sniff on the circuit-board as well.. if you smell something burning, take a closer look at that part of te board.

    Take a good look at it, and see if you can find any parts that look burned, have a scratch on it, or whatever ( as long as it doesn't look normal )..
    if you cannot find anything.. then it's time to whip out the multi-meter and test all components.. systematicly locate the source of shortcut :)
     
  3. AssMan

    AssMan

    Dec 2, 2000
    Minnesota, USA
    All ready did that. I think the problem is with the capacitors, because from what I know about capacitors, you're not supposed to get a signal through them, or you get a signal that diminishes.
     
  4. Probably shorted rectifier or diode, or cap, or transformer, or output section, or .......

    Really, you got to go through the motions of fault isolation. You need a soldering iron so you can break the circuit at certain points and try again, and also so you can test components out of circuit or else you will get a false reading in some cases. Then you need a variac and current meter so you can bring the power AC voltage up slowly and cut it off if the current gets real high, like 1 A idle is high for a 2 A fuse. Or you can just use about 50 2A fuses and replace every time you throw the switch and the fuse blows.

    Fun stuff. I do it all the time, but I have the proper equipment and knowledge. By all means, be safe or you will die, know what you are doing. Don't be stupid. You can figure it out and fix the amp through logical progression, though.

    Chris
     
  5. AssMan

    AssMan

    Dec 2, 2000
    Minnesota, USA
    I've got all those tools and have gone through it, and I think it's the second coil in the transformer, but I'll have to disconnect it to check. I just wondered if there were any common problems with this amp or ones like it, and I guess there really aren't. My assessment: it died of old age and abuse; it was made in 1985, and looks like it's previous owner didn't treat it very well at all. You wouldn't believe how many cobwebs and dust I found in it.