Hi i have a sound king skak20ra guitar practice amp worked fine for ages, but then i plugged a mic jack plug in wrong hole and all it does is make a fairly loud buzz now.All fuses are ok. Does anyone have any idea what it could be and if i could repair it myself, I have fairly limited electronic experience but can solder ok, pcd looks pretty basic if it was just a case of soldering a new cap or whatever hope one of you bright people out there can help
cheers Dave
Gonna take a lot more info than that; starting with 'which' hole could you possibly have plugged something into, which would kill the amp. My feeling is that the two are not connected.
More symptoms, please. Does it pass any signal at all (however noisy or distorted) when you plug a *guitar* into it?
jak
Sorry for the poor info jak What i did was plug a mic kack into the look socket on the back (dont ask me why) and then when i turned it on again all it did was buzz fairly loudly. none of the volume knobs or anything else works when i plug the guitar in just a constant buzz hope that will help many thanx jak Dave
Its possible that the loop skt has a break contact like the headphone skt disconnects the speaker in a domestic amp. It could be oxide on the contact causing a poor connection and allowing mains hum instead of the signal through to the final amp stage. With the amp unplugged - squirt the skt with switch cleaner (WD-40 might do) and work a plug in/out of the skt, dry off any excess fluid and try the amp.
thanx I.F i`ll give it a go and tell u how i have gone on cheers Dave
tried cleaning the jack as you said still with same problem of loud mains hum just looking on the cicuit board and there is a small component tda2030a, amplifier i think, that has 4 small burn marks around its solder joints on the pcb could that be the culprit would that cause the symptoms
cheers Dave
Probably. I don't see how plugging a mic into the loop jack could have caused it, though. Maybe it was something else you plugged in there?
In any case, it does look like it's knackered. You could possibly try to replace the chip amp circuit. for a generic schematic using the TDA2030a; or google your amp model ##...in fact, check out where two out of three reviewers had technical problems with the model.
Probably it was just time for this one to go to that Big Stage in the Sky...not your fault at all.
jak
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