Aiwa TPR-990H
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I tested from line-in and the right vu moves so i think that may have been how I had tested it last night. Probably bad information from me. Sorry.Superduper said:
Was yours totally dead, mine has some sound just very quiet and distorted.muto said:
Is there a way I can test if it is the dolby chip? I do get some quirky noise when the dolby is on which is different to when its off.
Just purchased the TPR-990K service manual for further analysis.
I'm wondering if i'll be able to use it to isolate this issue. Failing that I guess I will have to test my soldering skills and try and take out the function switch to clean properly.
Think i'm gonna need some of that expert help though again Norm.
I'm wondering if i'll be able to use it to isolate this issue. Failing that I guess I will have to test my soldering skills and try and take out the function switch to clean properly.
Think i'm gonna need some of that expert help though again Norm.
If you want to isolate and be absolutely certain whether the issue is related to those switches before moving on -- then.......
(1) find and bridge all the poles on the function and R/P switches where the audio circuitry runs through. With those locations bridged, then it should work clearly. Might be hard to bridge all of them with probes so you might have to solder temporary jumpers. It won't be easy to identify them all, but it's possible.
(2) Or, use your signal tracer or audio injector and trace like you did before.
(1) find and bridge all the poles on the function and R/P switches where the audio circuitry runs through. With those locations bridged, then it should work clearly. Might be hard to bridge all of them with probes so you might have to solder temporary jumpers. It won't be easy to identify them all, but it's possible.
(2) Or, use your signal tracer or audio injector and trace like you did before.
doc is this that the really nice one of ebay which sold a couple of weeks ago??? because if it is what a bargain if ya get it going lovely nick!!! good luck with ya repair! i was going to go for it but after reading your problems I think it would of been too much for me and been put in my "to do" shelf!!
Yes it is, was a great price though the problems are still being ironed out thankfully with Superduper help 
sort of wish i'd went for it really but i knew it would be popular!! but with the problems maybe not!!
I think you have to check it with oscilloscope. If i remember correctly it was totally dead. I'm not sure how i tested it. The signal was routed through integrated amplifier of the dolby chip. Signal was going in but got no output. Then i compared to other channel and it was easy to see how it should work.docs said:
Thanks muto, with the lack of an oscilloscope I will be trying to get someone to look at it for me.
Thanks to a sterling effort from Norm and countless hours scratching heads it was indeed the dolby IC for the left channel.
I bought some cheap and replaced it this morning and the left channel is now working as it should.
Although this box is a nightmare not just in terms of layout but in terms of how complicated the audio signal paths are this is a worthy box to fix.
It sounds great, looks great and is up there in terms of quality.
I'll be posting some pics in the collections thread soon.
Thanks again Norm for all of your help, I couldn't have done it without you, and muto for the heads up.
I bought some cheap and replaced it this morning and the left channel is now working as it should.
Although this box is a nightmare not just in terms of layout but in terms of how complicated the audio signal paths are this is a worthy box to fix.
It sounds great, looks great and is up there in terms of quality.
I'll be posting some pics in the collections thread soon.
Thanks again Norm for all of your help, I couldn't have done it without you, and muto for the heads up.
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