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Power Light Won't Illuminate

Discussion in 'Amps and Cabs [BG]' started by rockinroller, Aug 26, 2012.

  1. rockinroller


    Dec 6, 2010
    I just bought a new Acoustic B450 bass combo amp. Great amp--punchy, lots of power, wide range of EQs, etc. Guitar Center was clearing these out and I received a floor model from an out of state store. The amp light won't illuminate. I slid out the amp and verified the wiring was connected, the two point harness was plugged in, etc. and I even spliced in another lamp assembly I picked up at the local Radio Shack. Nothing.

    Does anyone have an idea of what could be the issue? The amp works fine--just no visual indication of power. Acoustic has a nice 3 year warranty but there's no service location near me and I'd have to have it shipped out to have this fixed.
  2. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    Take it to a tech and get him/her to correct your problem. Could well be less than the shipping costs. OTOH your warranty could be void. Your choice.
  3. Just the fact the OP opened it up and "spliced in another lamp assembly" has probably already voided the warranty....
  4. craig.p


    Sep 28, 2008
    New Hampshire
    What kind of lamp is it? LED, or incandescent, or neon?

    Where is the lamp voltage obtained? Direct from the AC line ("this" side of the switch), or from some low-voltage source?

    This would be a good application for a voltmeter because you could tell exactly what (if anything) is present at the lamp end of the wire pair.
  5. I bought a new B200H head over a year ago, and the light have never worked. I bought mine online, so I decided to not ship it back. The amp has worked flawlessly other than the power on indicator light.
    John Sr.
  6. rockinroller


    Dec 6, 2010
    I don't know what type of lamp it is. Radio Shack's fairly knowledgeable guy said he thought it looked like an LED. The light's two-wire harness plugs into a 2-hole female receptacle on a circuit board. That's the extent of my understanding of this situation.
    I have a house-type electric tester (that detects juice in a line) if that would work.

    I am inclined to align with Johntheson's perspective: Keep the amp and forget about the power light issue. Heck, with the absence of anything other than one-night gigs, there's no chance of leaving that amp on anyway, plus the cooling fans are loud enough to know whether the thing's running.
  7. craig.p


    Sep 28, 2008
    New Hampshire
    Ok, it sounds like an LED. No, an AC outlet tester (if that's what it is) won't work. You need a low-voltage voltmeter. You have either a bad LED or a bad driver circuit. But yeah, if the fan suffices as a power-on indicator, then I guess you don't need to go further. Another thing you can do is buy a cheap power strip with an illuminated rocker switch, and use that as the amp's power switch.
  8. rockinroller


    Dec 6, 2010
    Well maybe the Radio Shack replacement that didn't work either would never have worked anyway, as it was a standard Neon Light Assembly with 120VAC operating voltage and 95VAC firing voltage, based on the packaging.
    Is that possible?

    If so, where could I find a replacement light that I can 2-wire into the type of connection this Acoustic uses? Acoustic support is no use, as they do not provide an outlet for parts for owners.
  9. majortoby


    Jul 2, 2009
    Tampa, Fl USA
    I see this one of two ways: Either it's just a bad lamp, and totally NOT something I would sweat. OR the board receptacle isn't getting power, which indicates supply issues, which, IMO, is a much more insidious problem.
  10. craig.p


    Sep 28, 2008
    New Hampshire
    This is making no sense. The RS expert said it looked like an LED, but he sold you a neon lamp assembly?

    If you want to pursue this, you have to find out what voltage is at the lamp assembly end of that cable. Voltmeter time. Be careful in case it IS line voltage, 'cause that can knock you right into next week if you come in contact with it.
  11. rockinroller


    Dec 6, 2010
    Yeah, I chose the neon lamp assembly because it looked more compatible and similar to the entire harness I was trying to replace (the LED was just a small bulb at the end of two thin wires).
  12. 5port


    Oct 14, 2009
    LI,new yawk
    From your description it uses a micro minature bulb mounted on a small flat circuit board. We use them at work. These bulbs look like the minature bulbs you use to find on a Lionel train set. They dont last very long. The neon bulb should last for a long time and be much more reliable.
  13. seamonkey


    Aug 6, 2004
    It's probably an LED
    It's probably a hand wired part with wires that go from the circuit board to the front panel.
    It's probably wired up backwards and thus doesn't light.

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