Pioneer KEX-M900 troubleshooting

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vincegironda

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Joined 2013
Hi all,

I'm currently restoring a KEX-M900 which came to me as a dead unit.

So far I recapped the DC to DC converter

Recapped the main board, ASL board and DSP board

The unit now powers up, display is good, all menu's working too.

The problem is the unit has 4 pre outs and I have only one channel with good clean audio.

I would like some pointers on tracing the audio path to see if I can find where it's losing audio signal to the dead channels.

What I know so far-

I've tested 2 audio sources

Cassette working fine
Aux input working fine

Both with the same result - audio on one channel only

The dsp board is labelled FR FL RR RL where it outputs to the main board and into the ASL board, I intercepted the signal off all 4 channels and it's only outputting audio on one channel so I think the problem lies within the DSP board or maybe just before it?

I've come this far so would really like to troubleshoot and find the problem, any help or suggestions appreciated

I have a service manual pdf if required

Thanks in advance
 
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vincegironda

Member
Joined 2013
Perry Babin said:
What page is IC703 on?

If you have audio on the output terminals of 764, that's what's important. If the op-amp is working properly, you won't see signal on the inverting input unless you go back to the resistor in series with that input.

Does heating/cooling any of the DACs make a difference?
Click to expand...


So is it safe to assume if IC 764 has audio on the output terminals then the problem lies further along the circuit after IC764?
 
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