Burnt, burnt out, burnt up, whatever you call it, the part is damaged, and needs replacement.
Bad parts usually look no different from good parts.
Bad parts usually look no different from good parts.
The speaker will eventually fry if you leave it on for any period of time.
Disconnect speaker.
Get a schematic.
Then work through schematic checking voltages until you find something wrong.
Or alternatively, with it switched off, check all the components on the pcb.
Don't stop if you find one faulty component because sometimes one component failing will take others with it.
Disconnect speaker.
Get a schematic.
Then work through schematic checking voltages until you find something wrong.
Or alternatively, with it switched off, check all the components on the pcb.
Don't stop if you find one faulty component because sometimes one component failing will take others with it.
Agreed (and said already).
No, get a Service Manual. It includes the schematic, full parts list, and usually a lot of discussion of how its supposed to work.
Yeah...a good start.
Bzzzt! Error! So you put your Ohm meter across a resistor and it measures "wrong". What do you do? Replace the resistor? Not necessarily, because it's part of a circuit and you're measuring the resistor AND the rest of the circuit it's part of. In-circuit testing of components is only useful for opens and dead shorts, unless the tester has some more in-depth knowlege of how things work. For example, you power the thing up and put your 'scope on a signal input pin of an audio opamp, and read zero signal. It's broken, right? Not necessarily, and if you make that assumption, you'll go down the wrong path quickly.
Yeah, but again, it's all "in circuit".
So far nobody's suggested a cap tester either.
So back to the OP @EarthsDefect...
Do you have the test equipment and at least a little tech/bench experience? I'd hate to presume, but because of the questions, it seems like perhaps not. You're welcome of course to play and learn, in fact, that's probably the best way to learn. But it's not the best way to get something fixed. If you add up the cost of the suggested test gear, service manual (if you can get one), and the lowest possible value you can place on your time, you'll see quickly that you should just follow the original suggestion and have it fixed for you.
That's unless you don't really care if it's fixed or not, and want to learn about electronics. Like I said, it may be the best way, but certainly far from the easiest way. Starting with a broken device above your repair chops will most likely result in a smattering of new knowlege and a bushel of frustration.
But, it's your call.
Desirable, but I was an authorized Behringer repair shop for a good number of years, and all we ever got was schematics. I don't recall a manual on anything of theirs. Some may exist, but not for most models, and I never saw one for simple systems like the powered speaker. In fact it was often maddening that the schematic set often excluded the mains wiring and parts like the transformer.
Companies like Yamaha, Roland, Korg, etc produce terrific manuals, very complete.
Behringer doesn't release schematics, and in fact they still chase down the ones they find online. Elektrotanya used to have a lot of them, then they had to remove them. We are lucky to find their schematics.
I have found no problems debugging amps with a multi-meter using ohms range.
It just needs a bit of common sense. If you get a low reading around a diode or transistor just reverse the leads and you will get the high impedance on the diode/transistor. Resistors usually go open circuit and capacitors usually go short circuit. But I would check caps with an LCR meter in case they are electrolytic and losing their capacitance.
For a stubborn fault I have seen me remove all the transistors and check each discrete component while in the pcb. While transistors are out check them for integrity and Hfe.
I once had a transistor check ok for junctions but only had an Hfe of 1 !
You've just made my point perfectly!
You applied the one tool the OP is likely missing, and can't go out and buy: Experience. I'm pretty sure you didn't acquire that knowlege and experience by hacking your first ever amp.
Now, put yourself in a place where you didn't know all that, didn't have an LCR meter, and didn't know how to check a transistor at all, much less come up with Hfe.
Now, I don't know, and don't want to assume, but the original question was, "How can I fix this, I seen about testing for DC offset, it must be the problem but how can I fix it?" At what point along the line of understanding of electronics would you have asked a question like that?
Then this, ""Get the amp serviced" is not a option its too expansive and I would rather fix the problem myself, I know enough about what each component is and have the tools to fix it."
But when I asked about specific tools...nothing. And what is the key tool that's clearly missing? See, "not an option it's too expensive" is really incorrect anyway.
Ok, I've made the point.
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