Amp not working. Troubleshoot with me?

Discussion in 'Amps and Cabs [BG]' started by dancehallclasher, Mar 16, 2002.

  1. i've been using an Acoustic 150 head for a while, and when i got back from spring break, it doesn't work all of a sudden. nothing happens when i flip the power switch.

    the problem is not the socket.

    i have pulled out the fuse to look at it, but i really have no idea what i'm looking for. what does a blown fuse look like?

    any other ideas? i don't have the means to get this professionally fixed.
  2. A loose wire on the power switch perhaps? You're Amish and don't have elecricity? :)
  3. Ty McNeely

    Ty McNeely

    Mar 27, 2000

    I've never had to look at an amp fuse, but I'm assuming its probably going to be silver on the ends with a clear middle section. If it is, look for the filament inside the clear glass part....if its still intact (there's no break in it from one end to the other), then its OK. However if you can see a break and the clear section is somewhat black, it's probably blown.
  4. Check the fuse. It may look good, but not be good, but if it looks bad, it is bad. Can you dig it?

    You really need a multimeter to ohm it out and make sure the fuse reads as a short circuit.

    If you find out it is blown, don't replace it with anything higher than what the back of the amp says. If you do, you could do permanent damage to the amp if something is shorted inside. So many power transformers fried because a 5 cent diode shorts out, the guy puts in a 25 amp fuse, and then the power tranny fries before the fuse would ever blow. That 5 cent repair is now $100.

    Don't even think about opening it up if you don't know what you're doing in there. You can get killed very easy.


  5. Gman


    Jan 4, 2000
    Indianapolis, IN
    Absolutely right. There is NO other way to check a fuse. It may sometimes be obviously blown, but they are never obviously good...if you know what I mean. Just because it looks good, doesn't mean that the path is continuous. Every musician should have a volt/ohm meter anyway. Go get a cheapy from Radio Shack. It won't be pro quality, but it will serve your needs. And once you learn how to use it, you'll find more and more uses for it.

  6. i went to radioshack and got some new fuses today, the guy there confirmed that it was blown and helped me get the right kind of replacement. so i put a new one in, and flipped it on. it worked for five seconds until the new fuse blew and the amp started smoking. it was pretty scary.

    well, thanks anyway guys.
  7. camoe


    Sep 7, 2001
    Lafayette, CO
    Well, somethings shorting out causing an overcurrent. Most likely an electrolytic cap or the transformer winding. Bummer dude. Good luck.

  8. Primary

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