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Ampeg B3: smoke=bad?

Discussion in 'Amps and Cabs [BG]' started by heretic, Feb 8, 2005.


  1. :crying:
    I was cleaning my 115 combo with that air in a can (???) and when I put it back togeth and started to play I heard a "pop" and smelled burning. I took the amp head out and saw a small amount of white smoke. I know I blew something, but what is it? I have been having trouble with crackling in the volume pot (reason I was cleaning) could that be it? what to do... I don't know any places to take it near my area and I don't have a warranty as I bought it used. :crying:
     
  2. Special_Ed

    Special_Ed

    Oct 3, 2004
    Bring it in to a music shop to be fixed and be prepared to get raped in the wallet.
     
  3. Im a sock

    Im a sock

    Dec 23, 2002
    Central MA
    Smoke = Bad
     
  4. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Before you take it to a repairman and get wallet-raped, there's a few things you can do...
    If you have access to a multi-meter, get it! Once you do, start checking all your caps as that's most likely what went "pop".
    Also, while you have your meter, check any/all wiring in the amp with it.
    If you need any help with this, PM or e-mail me, and I can assist you, to a limit.
    If all that fails though, sounds like it'd be time to take 'er in.

    Ray
     
  5. I'm afraid I dont have access to one... nor would I know what to check (I'm an amp newb) I have a friend who has some experience with them though... I'll let him have a look at it first.
     
  6. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho

    If smoke came out of it, the smoke is likely from a localized area. You may well be able to see what that part is (discolored by heat possibly) or even track it down by smell to get it narrowed down.

    Still, even knowing what the part is that fried, unless you want to learn about electronics repair, you will be paying someone to fix it.
     
  7. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    +1

    That would be "true in general". :D

    Sounds like a trip to the tech. As an experienced amp tech, the first thing I'd do is a thorough mechanical inspection. Pull the chassis, and look around for the burnt or charred components (or area of the PCB).

    If you can't find one, or it isn't immediately obvious, then you'll have to do electronic troubleshooting, which can be a major pain. In a high power amp, I'd probably start by getting the schematic, then disconnecting the power supply outputs and making sure the power supply is working okay, then trace through the schematic "backwards" from the output stage, and "forwards" from the preamp, looking for the place(s) where the signal is present (or isn't).

    From a tech's perspective, a puff of smoke isn't necessarily a major repair. Parts go bad all the time. It's possible a good tech can fix your amp for a "minimum bench charge".

    Oh yeah, and another thought just occurred to me, a lot of those cheap Chinese fuses blow smoke when they pop. Have you checked your fuses?
     
  8. Passinwind

    Passinwind I Know Nothing Supporting Member

    Was the amp warm when you used the canned air? Some forms of that stuff can freeze components pretty quickly, and could easily crack a semiconductor's plastic case if it were hot to begin with. It can also cause fractured solder joints, which can lead to smoke.

    Best of luck finding a good tech! Sound guys and repair techs sure don't get a lot of love here. [​IMG]
     
  9. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Yep, smoke is bad....

    No telling what the smoke is from, but it wouldn't be from a "cheap chinese fuse" in this case. Especially if you smelled burnt stuff.

    Not to be a pain, but there IS a reason for that "no user serviceable parts inside, do not open" notice.........sorry.

    The canned air is fine stuff, but sometimes it will blow a piece of conductive crud into some place it shouldn't be. That sounds like it could have been what happened to you.

    We DO NOT recommend that a customer take their unit apart, or open it in any way.

    One reason is damage, as you discovered.

    The other is safety.

    Some parts of the innards may hold a charge and can give a shock even with power off if touched.
    Some parts that don't look important actually do have a safety function, and disturbing them can cause an unsafe condition.
    If you are not familiar with electronics, it is easy for a safety problem to be un-noticed. Something like a loose wire that is laying in the wrong place, etc.

    Take to a tech for repair. That's the best policy overall.

    Even to clean it out, a tech is best. A qualified technician knows what should and should not be present, and can identify and correct a problem with foreign material in a bad place easily.

    And, if the tech damages your unit cleaning it.....he better fix it free.....as opposed to the alternative......which you now have.


    "Techs only" area:

    I don't like canned air (compressed air in a can). I don't use compressed air to clean electronics, and I don't use it to clean chips off power tools. It can blow "stuff" deep into inaccessible and invisible places.

    For most "normal" stuff, I very much prefer turning the chassis over, and giving it a couple sharp raps with the other hand. A good policy after any repair, gets rid of solder specks etc.

    If I have specific reason to think some sort of foreign material is in there, I may turn the chassis a couple different ways, rapping each time, until I think "enough" stuff has come out to account for all of what I think is inside.

    Then I take a look around and make sure nothing is stuck where it won't shake out.
     
  10. Joe Beets

    Joe Beets Guest

    Nov 21, 2004
    Before you jump into anything, like a big repair bill, you might want to check the Combo Amps Megathread. It really makes you think about this whole combo issue. :eyebrow:
     
  11. The amp wasnt warm at all, so that may not be it. I know taking it apart wasn't not the smartest thing for me to do but I had to get rid of the dust that was on the pots and what not. It was snapping and popping all over the place.

    I'm not sure if it still works... I turned it off the second I smelled something. I don't think its very safe test it now.

    This thing has brought me more trouble than pleasure, I think maybe when I get it repaired I'm just going to sell it and save up for a amp+cab...
     
  12. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Don't use compressed air to clean scratchy pots. Use CAIG DeOxit.
     
  13. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Agreed. One of the most useful products ever made. (At least if you're dealing with a lot of scratchy pots). :)
     
  14. Many people don't know it, but amps actually don't operate on electrical circuits. They run on smoke, and when something happens to let the smoke out, it costs big bucks sometimes to have a tech stuff the smoke back into the amp. :crying: :D :D
     
  15. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    This gets my nomination for worst joke of Feburary...

    Ray

    Edit: I was going to make a play on words of AmpegInsider's suggest to rap on the amp, but thought it'd be a bit lame :p
     
  16. SuperDuck

    SuperDuck

    Sep 26, 2000
    Wisconsin
    One of my teachers in college would use that one all the time. He wore a bowtie, every day. I think he had one that spun and made a funny noise.