Hi again, I'm back with a 4th project....
The people that have made comments and tried to help on previous questions have been a BIG help to me, being only a beginner at all of this, I know only so much...
I have another amp, a Harman Kardon HK-3380 integrated amp I just picked up for literally £8.
Problem is, the previous owner stated in a house move, it just stopped outputting sound, on when I got it I did all the basic external tests and nothing, I opened it up to find 2 of main 2 fuses had blown, so I bought 2 more, after that, switched on and the fuses did not blow, however, still no sound, not even a speaker hiss, but I found 2 of the transistor regulators right next to the main electrolytic caps were heating up to burning almost, so, I was thinking, in my knowledge of amps, they usually get stuck in speaker protect mode when a amp is switched on, but this amp switches on ok and I can hear the 2nd click of the speaker relay coming on.
The only other thing is that when I held it at a angle, it switched itself off, so maybe a broken cold solder joint?
I'll check all of this out for the basic issues shortly, but I'm thinking it has possibly 1 or more blown transistors?
The people that have made comments and tried to help on previous questions have been a BIG help to me, being only a beginner at all of this, I know only so much...
I have another amp, a Harman Kardon HK-3380 integrated amp I just picked up for literally £8.
Problem is, the previous owner stated in a house move, it just stopped outputting sound, on when I got it I did all the basic external tests and nothing, I opened it up to find 2 of main 2 fuses had blown, so I bought 2 more, after that, switched on and the fuses did not blow, however, still no sound, not even a speaker hiss, but I found 2 of the transistor regulators right next to the main electrolytic caps were heating up to burning almost, so, I was thinking, in my knowledge of amps, they usually get stuck in speaker protect mode when a amp is switched on, but this amp switches on ok and I can hear the 2nd click of the speaker relay coming on.
The only other thing is that when I held it at a angle, it switched itself off, so maybe a broken cold solder joint?
I'll check all of this out for the basic issues shortly, but I'm thinking it has possibly 1 or more blown transistors?
If the speaker relay pulls in, the power section is probably OK. Check and refer to the service manual for voltages.
Burnt fuses mean an excessive current which might have fried something before the fuses popped out. They never burn for no reason so you should avoid replacing them and turning a unit back on before doing a bit of probing and checkup in the concerned area.
Excessively hot regulators mean either they shorted to ground or that there is a massive current flow through them. The output relay reacts only to abnormal electric conditions at the speakers output, which means the fault might lie before that, for instance in preamp section which does not feed the signal. If the topology allows, start from unplugging all stages from the PSU and measuring all voltages there.
Excessively hot regulators mean either they shorted to ground or that there is a massive current flow through them. The output relay reacts only to abnormal electric conditions at the speakers output, which means the fault might lie before that, for instance in preamp section which does not feed the signal. If the topology allows, start from unplugging all stages from the PSU and measuring all voltages there.
Moving to solid state where power amplification is discussed.- Status
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