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General amp problem question!

Discussion in 'Amps and Cabs [BG]' started by Bluedragon50, Feb 19, 2005.


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  1. Bluedragon50

    Bluedragon50

    Feb 18, 2005
    Ok, i own a rogue RB60 amp, and lately it hasn't been working, i turn it on, and i hear it come on, but when i plug my cord into the input jack, its as if no juice gets to the guitar, (its not the cord, cuz it works fine on my smaller amp), i believe the problem lies in the input jack. should i open up the back (really don't want to), or take it somewhere..please help. :crying:
     
  2. I doubt it's worth taking somewhere, unless you know a reputable amp repair guy that's relatively cheap (and it kinda sounds like you don't).

    Does it make any noise when you wiggle the cord in the input jack? If it's the jack you possibly may hear an occassional popping or crackle when you wiggle the cord. If you don't hear anything then, it could be anything else, from a bad solder connection to a fried transistor to a blown speaker....You say you hear it come on? Is any sound (hiss) coming from the speaker at all? If so, that's a good sign, that eliminates the blown speaker and means the power amp part of the circuit is most likely functional.

    Usually input jacks are easy to replace, but on some low-cost amps they are directly soldered to the circuit board, then it's a royal PITA to replace them.

    You could take the back off--unplug it first!!!--and see if the input jack is accessible directly--does it have a couple of wires going to it, or is it soldered to the circuit board? If it's not soldered directly to the board, buy a new input jack from Radio Shack and learn how to solder, even if that doesn't fix your problem, you'll learn how to solder.
     
  3. Bluedragon50

    Bluedragon50

    Feb 18, 2005
    yeah but its not just the input jack, its the low inpout jack, outjakc, and all the others, i mean i know it turned on, cuz i heard a low boom sound that i always here when i turn it on< is that normal for a 60watt combo amp?
     
  4. Many amps will make a small "pop" or "boom" when turned on. So if you still hear that, that at least means the speaker isn't burnt out.

    But if you aren't getting anything with any of the input jacks, you've probably got a more serious problem. It's hard to diagnose an amp problem over a forum thread.....and repair techs aren't cheap.

    Unfortunately, this isn't a high-quality amp, so it may cost you more to repair than you paid for the amp originally. Sorry for the bad news....
     
  5. stropsrats

    stropsrats Owner: www.kennedyaudio.com

    Feb 14, 2005
    Valders, Wisconsin
    When you turn off the amp and wait a bit, do you hear
    a shooshy sound?
     
  6. Bluedragon50

    Bluedragon50

    Feb 18, 2005
    no, i just hear a slight soft boom sound when i turn it off and on
     
  7. stropsrats

    stropsrats Owner: www.kennedyaudio.com

    Feb 14, 2005
    Valders, Wisconsin
    You should be hearing a small pop after you turn it off. If not, it may well mean you have blown something out. If you had it hooked to extra external speakers, it will be the transformer most likely. If not, it could just be the capacitors. Anyway, they have to discharge which is why you should hear a pop of something after power off. It's possible you threw the internal settings out of whack too if you were feeding a pedal signal with the amp off. Could just need recalibating - maybe it's a blessing in disguise because you could replace the capacitors with better sounding ones or the transformer with one that will handle more speakers. All depends on if you are happy with it.
     
  8. This is a solid state amp, there is no output transformer. And what capacitors are you thinking of? And there are no "internal settings" or anything that "needs recalibrating" So in other words, everything you are saying is gibberish. Have you ever repaired an amp? :eyebrow:
     
  9. stropsrats

    stropsrats Owner: www.kennedyaudio.com

    Feb 14, 2005
    Valders, Wisconsin
    Just trying to help that's all.
    Advise is free. Anyway if you're so hot about it, maybe you should look at an amplifier and find the transformer. It's a little square box, right? No capacitors, ok. Yeah ok,
    you have to understand something bill. You're from NASHVILLE. That's in Tennesee if I can say that without consulting a map.

    jeeeze
    I'm outaa here.
     
  10. Warwick player

    Warwick player

    Dec 31, 2002
    Bucks, UK
    After all that... :rollno:

    Blue Dragon, I would advise you if to at least take it to a "Technician"(sp) just to get his opinion, not nescessarly to get him to fix but just see if he can diagnos the problem. And if possible to get him to price what the cost would be to fix it. Then this will really tell you whether its worth the cost.

    As Bill said, it is incredibley difficult to diagnos amplifier problems like this, as it could be anything as simple as the input socket and it having a dry joint, to a transistor being blown in the preamp or power amp stage.

    Sorry that this isn't really a solution, but more another option.

    Good Luck! ;)
     
  11. Advice is free, it's worth what you pay for it, but I've repaired more than one amp and constructed amp components from scratch. And I'm an engineer. I know a fair bit of electronic theory and amp design crap.

    Yes amps have capacitors. And a transformer or two. But you're just throwing out buzzwords. How do I know this? You throw out phrases like "replace the transformer with one that will handle more speakers". Huh? If it were a power transformer, the amp wouldn't come on. Period. No pops or thumps. IIRC, this amp does not have an output transformer, it's solid state. (If it were a tube amp, and the output transformer were fried, you most likely wouldn't hear any pops or thumps on shutdown or startup either. And tube amps generally have impedance taps to allow you to match the external speaker load, so no need to change transformers for that!)

    Sure, there could be a capacitor that fried, but most modern day caps are decent enough. "Replacing them with better ones" doesn't fix anything. Though there certainly could be an open cap, a tech wouldn't just start replacing them, and you almost certainly wouldn't be able to improve the sound quality by "replacing them with better ones".

    So shut up with the BS. Some of us almost know what we're doing.

    Back to the problem at hand: it's most likely something that I would consider minor. But the difficulty is tracing the problem to locate the bad component. Even experienced amp techs can spend hours on a circuit locating a bad solder joint.
     
  12. Bluedragon, I apologize for being rather obnoxious with the other guy, I truly do want to see you fix your amp--cheaply--and I get rather upset when I see people throw out goofy responses. It could be something simple like a switching input jack (some jacks will make or break contacts when you plug them in) that isn't closing properly. As Warwick player said, take it to a tech--NOT the local Guitar Center or Ma and Pa Music store, but a real amp repair shop. I know, they're hard to find. Definately ask what he would charge to diagnose it, don't just give it to him and say "fix it".

    If you were from the Nashville area, I'd gladly look at it for you and try to diagnose it (free of charge even).
     
  13. stropsrats

    stropsrats Owner: www.kennedyaudio.com

    Feb 14, 2005
    Valders, Wisconsin
    Hey, those of us with the real experience know what comes next. You walk in and they say, well, it's if $50 just to look at it, of course we will apply that to your repair, but it isn't refundable. They you pay them. Then you come back in 4 weeks after they try to find the transistors that maybe are blown (they can't tell for sure) but since they are not made anymore, they can't be sure if they found the right ones.
    And if the transformer is going, they can't be sure that the insulation on the wires will last but they are sure that it's not the transformer because it wouldn't come on at all if it were, uh, that is you woudn't here the pop but that's not to say we know what that pop it from, it coulbe be anything, a capacitor or uh, maybe it's out of calibration or something...
     
  14. Then why don't you volunteer to take his amp and diagnose it?

    I'll do you one better: if he gets the amp to me, I'll look at it AND attempt to repair it for just the cost of the parts, plus shipping and cost of a schematic (if available). Fine print: some low budget amps have surface-mount components on the PC board. This almost always makes the PC board a "throw-away".

    Care to match that offer?
     
  15. stropsrats

    stropsrats Owner: www.kennedyaudio.com

    Feb 14, 2005
    Valders, Wisconsin
    Tricky tricky. But OK, I"ll bite. If it is a class A amp, class AB amp or even a class B amp. But he still has to open up the back, I don't want the speaker cabinet.
    Also if you want to assist you can get the transister PNP and NPN number and do the lookup for me, that way the replacement parts are at least agreed upon in advance and the cost is up front, I would guess it to be about $12 for each pair, assuming I (i.e. or YOU) have an account at a supplier that will be able to fill that order. I'm hoping you agree that all the transisters will need replacing if even one is bad. I will be able to test them. That's about the only hangup, but it's about the only way this buy will ever get it fixed too, otherwise we should maybe tell hime to drop it on their desk if there is a nearby technical school or start shopping eBay.com
     
  16. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    play nice people. :rolleyes:
     
  17. I give up. This guy's throwing out pure BS. (sorry, mods.... Please delete all of my posts on this thread, sorry I even tried to help somebody.)
     
  18. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    don't worry about it NB, you got a little hot under the collar, but i've seen worse. in any event, you've been a help to tons around here.

    stropsrats, no offense, but it really does sound as if you're haphazardly spouting off techinal sounding jargon. and no, i'm not playing favorites, i know enough about amps to tell the difference. ;)
     



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