cdp-x33es right channel distorted

Hi there,

I bought a defective sony cdp-x33es, the problem with the player is that the right channel is distorted.
After changing all the red Duorex II caps (which were almost all leaking) for Nichicon Finegold caps the problem is still the same, but if i let the player play for 3 minutes the right channel is suddenly good again...

Any idea what else could cause this problem?

thx!

Rubbereend
 
It could be many things. A check with a scope would pinpoint the section at fault in seconds.

It would be worth removing the mute transistor for that channel as these can be damaged by 'hot plugging' RCA outputs into some types of partnering equipment.

Check the relay isn't 'stuck' as this also mutes by shorting to ground.

You can determine if the problem is in the analogue or digital sections by swapping the DAC outputs over and seeing if the fault changes channels or not (4 connections to swap).

If the board is still contaminated then do not be afraid of washing that area in hot water.
 
Thanks for your reply, i don't have a scope, so i can't check that...
Where can i find the mute transistor?
BTW the sound from the right channel isn't muted when i start playing a CD, it's distorted and after a couple of minutes gradually gets better and better...
If i use my DTC-57ES as a DAC there's no problem with the sound, so i guess the problem is in the DAC section of the cd player.

greetings,

Rubberend
 
The transistor is just something to eliminate. They can fail in a non linear way and that would cause distortion. Its unlikely, but you have to check it.

The scope really is the diagnostic tool to use, without one we are just stumbling around and looking for ways to to prove/disprove the fault is in a certain area.

There are two transistors, one for each channel (see attached). You can remove the appropriate transistor or if it is easier just remove the 22 ohm resistor.

If you suspect contamination is the cause then you must clean the board thoroughly. Also beware that contamination can eat and corrode into PCB traces and other components.

If i use my DTC-57ES as a DAC there's no problem with the sound, so i guess the problem is in the DAC section of the cd player.

So that confirms the problem is most likely in either the final analogue stages or perhaps around the DAC.

Perhaps the contamination theory is the most likely.

Post #10 here:
Washing an amplifier board
 

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If you happen to have a multimeter, you could probe the DC voltages throughout the signal chain from the DAC to the output and compare the L and R channels, and/or compare the levels at start-up (with distortion) and a few minutes later (with less distortion). The expected levels are indicated in the schematic from Mooly.
 
Back again after a good cleaning of the board and re-soldering some questionable parts on the board, but i am happy to tell you that the cleaning worked perfectly!
Now i have 2 crystalclear channels right from the start!
Thanks guys!!, also to MonoloMos for telling me to remove the big Nichicon before cleaning!

Greetings,

Rubbereend
 
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