Philips CD303 with distortion and noise

[_Attila_]

Hello,
I have trouble with my loved CD303, and just can't help myself.
For the story, I acquired it for over1 1/2 year and until a couple of days it was perfectly working. Just a problem with the tray that would't fully close or open since 6 monthes.
Now for the problem: I was listening to some music as the player gave some loud noises from itself. The noise was very short, about 2 sec abd the kind of one which goes under your skin and that you can feel in your whole body. After this the player stopped. Turned it on and off a couple of times didn't changed anything: it just didn't wanted to spin. Until I pressed the tray. The cd was spinning and started to play again. As I was in hurry, I didn't payed attention to anything else.
Next day, I wanted to listen to some cds: The right channel just outputed some distortion noise, left channel had no problem. After left it warm up for 30 min or so, the distortion "ALMOST" disappeared. I said almost because you still can hear it on quiet passages and by carefully listening. On top of this: the right channel has very very low bass in comparisom with the left channel.
Yesterday, as I turned it on, there were some blank noise: no cd inserted, but the loudspeakers were crying... I had no scope o it, but "fortunatly" an equalizer: the noise on the high frequencies is almost continous, and periodical in the bass range (in case it could help someone for diagnostic!).
After a little warm up, the noise disappeared. But the right channel still has distortion and almost no bass output.
I thought on a cold joint, but not sure and I don't know of to start with this unit. So I would appreciate every help!
Thank you a lot!

ps: I searched the forum, found some treads about joint problems, but I couldn't help myself with them...
ps2: sorry for my english :/

[poynton]

This sounds very much like one or more dry joints, probably in the power supply.

It would be a good idea to overhaul the PSU board with new capacitors in any case, checking for dry joints as you do the work.
It is not necessary to use "top quality" (expensive) capacitors in order to get the player working.

Warning. Do the power supply board only first. Do not replace parts on other boards as you may introduce faults there makinf future troubleshooting more difficult.

Andy

[_Attila_]

Thanks for your answer! I just resoldered most of the joint, it doesn't change anything. I'll do the rest as soon as I have a little bit time
Another question: on the heatsink, 5 transistors are mounted. 4 have a silver backplate, but the second from left looks gold. Could it be that this one is burnt out?

[poynton]

Originally posted by _Attila_
Thanks for your answer! I just resoldered most of the joint, it doesn't change anything. I'll do the rest as soon as I have a little bit time
Another question: on the heatsink, 5 transistors are mounted. 4 have a silver backplate, but the second from left looks gold. Could it be that this one is burnt out?

It would help if you posted a photo so we can see what you mean.

Andy

[_Attila_]

Ok, here are 2 pics from what I mean: pic1 and pic2.
On the pics, the left transistor has a dark gold/light brown color on its metal plate, the right one has the "normal" silver color. The one with the dark color color is the second from left when facing the open unit (tray is then front left!). The 4 other (eg. 1st, 3rd, 4th and 5th if counting from left and facing the opened unit) have the silver color!





Now, another question: on the next 3 pics, you can see some solder joints. These are as I found them! Are they "normal" (factory joins), are as my unit been modified? They really look ugly, and for now I din't do anything to them!







What do you think?

[Mooly]

Is the "no bass" a clue. A coupling cap perhaps or open circuit print somewhere. If the left channel is OK that's a big clue.

[Mooly]

I see you are probably still under moderation
Do you have a manual ? If you can isolate (unsolder) the left and right outputs from the DAC to the output filters (OpAmps) and just swap them over. See if the fault transfers to the other channel. Do you actually have a 'scope there ?

[poynton]

It does look as if someone has resoldered some joints previously.

In post 1, did the noise at switch on come from both channels or only the right?

Andy

[_Attila_]

Ok, here we go:
unfortunatly I don't have the service manual, and for now I just can't afford it
The left channel works normal, nice deep and clear bass, no crack, hiss or distortion.
The right channel has a lower output, very distorded. It sounds like if it was "hanging" on the cd (don't know if you understand what I mean: sometimes my car cd-player hangs for 1 or 2 seconds on a track, producing a very high noise, totaly distorted, which is going directly in your nerves ).
Saddly I don't have a scope, maybe (but really MAYBE!) I could get one from work for an evening!
Mooly, could you please be more precise? Maybe a diagram?
Poynton: I can't remember, I was focused on the right channel, so I didn't payed great attention to what was coming from the left.. saddly! For now, I don't have this noise when I power the cd player on. It's really quiet, right and left channels

BTW: how to gain access to the main electronic? I can't open the surrounding without damaging it, what I really would avoid! Any hint?
And I must admit, I feel more conrotable with good old solid state amplifiers or receivers than with that baby here...

[Mooly]

Hi,
Have you tried searching for a manual on the forums -- someone must have one !! If the left channel is OK that means 95 % of the player is working normally. It really does sound like something silly. A PSU problem would affect both channels.
Just re-reading post #1. For the player to stop ( on it's own ? ) then that does sound like something else. Those two things, left channel OK and Right distorted and stops on it's own don't seem related really. No spillage or anything -- cats seen it many times.