Noise problem on SONY DCP1000

[MarinBNM]

Hello, sorry I'm writting on english, but mine german is so bad.

 

Here is the problem:

 

One night I did noticed strange noise on L channel, some noise....but sound on L was okay, and during louder parts in movie you can't hear noise because isn't high in level. Than I did go to investigate what is about....everything was normal, also I try to use Lc output but same, even I changed output driver SSM and TL072 before it but same. but I noticed that on AIN (8ch external input card) L and Lc level shows -600dB, where else are -90dB normal....i did unplug card and than noise is gone....I was think is because of bad AIN card....but after some days noise is here again, symptoms same as first time, but noise is quite low now...and noticale only during silence parts.....

 

So if someone have any ideas, also I did suspect on AOUT board but that -600dB don't make sense in AIN calibration menu, -600dB also shows on all channel when AIN board isn't in it.

 

thanks!!

[thx-mike]

Dear Marin!

 

Search on the Cable connection from the 25pin SUB D on the AOUT Card to the all Amplifiers, mainly the Left one, look out for Shield-Connection between and with the other both wires for high and low in this single signal cable.

 

It could also happen that the AMP itself makes the Problem, does the failure sneak to an other AMP when you plug the Left Signal wire to an other AMP?

 

good luck

Michael

[MarinBNM]

HI,

 

problems is only in output, I normaly try to switch channel on amp but same....also there aren't any cable issues here.

 

One thing more is to try replace e-potmeter.

[MarinBNM]

I did do complete diagnose today, problem was in DAC CS4328 Vref voltage, on others normally is 3,6V...on "noisy" one it was only 1,4V due failure of capacitors on Vref (pin 28 of DAC). Now voltage is back to 3,6V and is working fine.