So i have Harman Kardon AVR 220 receiver and when i power it it shows everything, but there is no sound coming trhu the speakers tried all inputs and all outputs, tried reseting, tried visually detect blown parts like capacitor or resistor visually they look good, i found service manual on internet, downloaded it looked for schematics and find out that all inputs go thru some sort of decoding board, because wires comes to this bord, then goes out to the main amp and then next one, plus to headphone out, i will be trying to plug headphones and see if if there is a sound from them but i dont have 3.5 - 6.3mm adapter right now, also i've seen that mosfets on main amplifier was soldered by a technician maybe, because solder joins doesnt look like others - made by factory... so i wanted to ask for the help if someone had similar problem and knows how to repair it? dont say - go to repair shop, because i've already tried that and they said that they dont repair harman kardon receivers....
If you know how to check for dry solder, do it.
Next, try soldering the ics that normally remain powered in stabdby. This involves the system controller.
You can check whether the power amps work if the speaker relay comes on. If this works, then you have serious problem. Looks like somebody already tried this.
If the above does not solve the problem, then nothing can be done except by HK.
Gajanan Phadte
Next, try soldering the ics that normally remain powered in stabdby. This involves the system controller.
You can check whether the power amps work if the speaker relay comes on. If this works, then you have serious problem. Looks like somebody already tried this.
If the above does not solve the problem, then nothing can be done except by HK.
Gajanan Phadte
I didn't found bad soldering, i didn't open the front panel yet, but tried using method witch i saw on youtube video - tried connecting to all inputs and see if they work with headphones but got nothing, amps also dont work, click sound can be heard when receiver comes out of the st-by mode, display shows everything but no sound from all outputs, even heaphone jack, all inputs seems to come in to special big board i think its dsp board tryed to take it out but i dont want to break it. It was given by my friend, witch he founded, to be thrown away to dump in norway, he said "you might fix it, because its working but has no sound"
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Its nice to have something like that, more nice if it had been working. You don't loose anything if nothing improves with your attempts, only your time.
You can check whether the power amp works...
Finding the power audio amps, you can check whether it is working, just by cliking with a screwdriver. If it doesn't give that annoying noise in the speakers or the headphone...further it is your adventure.
Enjoy
Gajanan Phadte
You can check whether the power amp works...
Finding the power audio amps, you can check whether it is working, just by cliking with a screwdriver. If it doesn't give that annoying noise in the speakers or the headphone...further it is your adventure.
Enjoy
Gajanan Phadte
Hi Sony
I'm a total noob when it comes to amplifier repairs but im trying to teach myself how to do it. I had a Harman Kardon AVR 2550 for along time that switched on like normal,
it had the same symptoms as yours, relay clicked switching the amp section on and everything but no matter what I connected to it, there was no sound at all.
After extensive testing of what I thought was problematic parts, I couldn't get anykind of readings but then I figured out that everytime I touched one of the probes to the amps chassis, I got a reading from the output transistors and other components. I realised that there were a lot of screws missing in the amp. Not sure if this applies to all Harman Kardon amps but all or most of the pcb's in the amp have bare contacts on the solder side of the board that needs to be grounded properly on the chassis, it this isn't done, then the amplifier will not work and pass any current or signal. So I suggest you look and make sure that every screw is in its place and if not, replace any missing screws, hopefully its a ground issue and grounding all the major components will turn the amplifier section on and give you readings.
Vishen
I'm a total noob when it comes to amplifier repairs but im trying to teach myself how to do it. I had a Harman Kardon AVR 2550 for along time that switched on like normal,
it had the same symptoms as yours, relay clicked switching the amp section on and everything but no matter what I connected to it, there was no sound at all.
After extensive testing of what I thought was problematic parts, I couldn't get anykind of readings but then I figured out that everytime I touched one of the probes to the amps chassis, I got a reading from the output transistors and other components. I realised that there were a lot of screws missing in the amp. Not sure if this applies to all Harman Kardon amps but all or most of the pcb's in the amp have bare contacts on the solder side of the board that needs to be grounded properly on the chassis, it this isn't done, then the amplifier will not work and pass any current or signal. So I suggest you look and make sure that every screw is in its place and if not, replace any missing screws, hopefully its a ground issue and grounding all the major components will turn the amplifier section on and give you readings.
Vishen
i did found that there is separated board for rear speakers of the channel, and i finded out that all inputs goes to some kind of dsp board that i mentioned earlier, from there most of the inputs goes to main amp (front speakers, center, sub) and two of them goes to separated amp ( rear speakers) so i was wondering if i can plug those inputs from dps bord out, and give the signal to that separated amp - from elsewhere like mp3 player to see if its working... there is lots of transistors on that board and its big, and one thing its smells like something was burned there.
the few avr 220's i've had for repair (no sound) all turned out to be low voltage regulator troubles and two required replacement of the ic handling the incoming audio for vcr 1 (not sure why i can only assume whatever source device was used killed this input)
before re-routing signal to amp sections try to find where the trouble is.
before re-routing signal to amp sections try to find where the trouble is.
i think that trouble is in that "dsp" board i tried to remove it but it wont come out that easy as i thought i dont want to break it, i will try again, that board has lots of caps transistors toshiba chip and lots of other smd ic's
im still noob when it comes to audio tech too, i made few projects https://sites.google.com/site/1sonyzz/home/elektronika/projektai (use google translate, because its in my native language) but i dont feel that proud of myself now, i dont made anything past half year...
so all the supply line voltages are ok? they must be since you've already narrowed it down to the DSP section. any leads as to what's producing the burnt smell?
its the processor board the biggest of them all, there all audio imputs comes in to it, then goes out to separated boards...and about voltage lines i've spotted one resistor that looks different from all the same resistors in that place near voltage regulators in think, also one off the regulators line was changed i think because it has metallic backside while others do have plastic backside touching the heatsink. I still didn't put out that processor board no matter what i tried, without breaking it
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