Hi all,
I have a problem concerning a non-DIY audio product, but where I recon a lot of you can help me with.
I have a Harman Kardon AVI 250 THX multichannel amplifier. Due to stupidity of my side, an earthloop occurred taking out the frontchannels of the 6chanel direct in. I¡¦ll describe the symptoms:
- Derectly no sound from the right channel when using the 6ch direct input
- Shortly after no sound from both front channels, and an awful pop so now and then when turning the volume nob.
I decided to have a look inside and figured out how the amp basically works, but I was uncertain on what to do. So, because time seems to heal sometimes, I tried hooked up a source and a test speaker. So, after opening up and doing some prodding and stuff the symptoms were:
- No sound at all from all sources on all channels
- Only from 0 dB and up some faint sound from the source can be heard
Still believing that time can heal I tried it again the next day, and hey! The sound was back, short of the front channels of the 6ch direct input. Figuring out with help of people that it could be the opamp directly behind the input of the frontchannels, I got myself a new one, soldered the old one out, popped in the new one, hooked up a test speaker and a source to the front channels of the 6ch direct input and¡K YEAH¡K it worked ƒº . So, I hooked up everything, and enjoyed some nice listening from a CD, no problems there. Then, when wanting to watch a movie and use the THX settings weird things started to happen. At first, this setting worked fine. After a wile (I was doing something else for a wile) I returned and found that only the front channels were producing sound, while in the THX setting. Also, when using the IR remote, the left surround channel squeeked¡K Turing the amp on and of resulted in:
- No sound at all from all sources on all channels
- Only from 0 dB and up some faint sound from the source can be heard
So, I ripped (carefully of course) everything out, hooked it up to the test speaker and tried it, and it worked again¡K this happened once more, and even once more, but now it is definite. The sound won¡¦t come back (only at around 0db some squeeling can be heard).
I think this is about enough info I should give to state my question: What can be wrong, and how do I solve it (except from bringing it back to the store and have it repaired, for which I don¡¦t have the money). As the amp is built up out of modules I think it might be either the coupling mudule (with I thing the main pre-amp on it) or the DSP board (in which case I am probably f¡K..d)¡K. What are your honorable opinions?
I have a problem concerning a non-DIY audio product, but where I recon a lot of you can help me with.
I have a Harman Kardon AVI 250 THX multichannel amplifier. Due to stupidity of my side, an earthloop occurred taking out the frontchannels of the 6chanel direct in. I¡¦ll describe the symptoms:
- Derectly no sound from the right channel when using the 6ch direct input
- Shortly after no sound from both front channels, and an awful pop so now and then when turning the volume nob.
I decided to have a look inside and figured out how the amp basically works, but I was uncertain on what to do. So, because time seems to heal sometimes, I tried hooked up a source and a test speaker. So, after opening up and doing some prodding and stuff the symptoms were:
- No sound at all from all sources on all channels
- Only from 0 dB and up some faint sound from the source can be heard
Still believing that time can heal I tried it again the next day, and hey! The sound was back, short of the front channels of the 6ch direct input. Figuring out with help of people that it could be the opamp directly behind the input of the frontchannels, I got myself a new one, soldered the old one out, popped in the new one, hooked up a test speaker and a source to the front channels of the 6ch direct input and¡K YEAH¡K it worked ƒº . So, I hooked up everything, and enjoyed some nice listening from a CD, no problems there. Then, when wanting to watch a movie and use the THX settings weird things started to happen. At first, this setting worked fine. After a wile (I was doing something else for a wile) I returned and found that only the front channels were producing sound, while in the THX setting. Also, when using the IR remote, the left surround channel squeeked¡K Turing the amp on and of resulted in:
- No sound at all from all sources on all channels
- Only from 0 dB and up some faint sound from the source can be heard
So, I ripped (carefully of course) everything out, hooked it up to the test speaker and tried it, and it worked again¡K this happened once more, and even once more, but now it is definite. The sound won¡¦t come back (only at around 0db some squeeling can be heard).
I think this is about enough info I should give to state my question: What can be wrong, and how do I solve it (except from bringing it back to the store and have it repaired, for which I don¡¦t have the money). As the amp is built up out of modules I think it might be either the coupling mudule (with I thing the main pre-amp on it) or the DSP board (in which case I am probably f¡K..d)¡K. What are your honorable opinions?
Just a picture of how the amp is set up:
So where could the problem be? (the rectangular bloks where all the line in's are going and the rectangular block in the 6ch pre-in board are supposed to be analogue switching controls...
An externally hosted image should be here but it was not working when we last tested it.
So where could the problem be? (the rectangular bloks where all the line in's are going and the rectangular block in the 6ch pre-in board are supposed to be analogue switching controls...
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