Not sure what to do with CD2

[mschwilson]

Hi.
I have a Cambridge CD2 that is a bit poorly,and I could do with a little help to sort it out.
The problem is,when I have the player is on for a while(a couple of hours),it starts to give a mildly distorted sound,a bit like the sibilance you get off a mistracking record deck.
Though this is not really nasty,it is very noticable.
I have read other threads which discuss problems relating to the chips,but before doing any work on them I need to know whether it may be something else.
The deck itself has a CDM4/11 transport,and has "issue 3" printed under the DAC section.
Another small fault is"ERROR 1" during switch on,on both displays,though I suspect this may be normal.
I have only a basic knowledge of electronics,so any help would be much appreciated.
Thank's for your time.

 

[Extreme_Boky]

Hi there,

It seems one of the IC's is affected by temperature drift. Probably one of the voltage regulators. Some "High End" British CD Players use zener diodes for voltage regulation with high power drop-down resistors. These (both, zeners AND resistors) usually burn the PCB around them...

How to figure where the problem is? Buy a freeze spray and wait for the player to start playing up. Use the freeze spray and spray one component at the time. Start with voltage regulators which dissipate most heat. If you get lucky and spray the faulty component, the sound should click back to normal for 2-3 minutes before it becomes doggy again. Once you're finished with voltage regulators, start with IC's… until you find the mother that causes the grief…

Good luck!

Regards,
Extreme_Boky

 

[mschwilson]

not sure what to do with cd2

Many thank's for the info,it is much appreciated.
Luckily I happen to have some freeze spray that's been hanging around for as long as I can remember,never thought I would have a use for it.
I'll have a look at the player today and see what I find.
After I posted the initial question yesterday,I tried the player via its digital output through Marantz DCC,and the cd player seemed to be ok with this,and I had no distortion problems(at least I was not aware of any),so I suspect faulty chips too.
May I ask a couple of thing before I go..

1.If I chose to use an outboard DAC,would there be any chance of the faulty chips damaging other components if used regularly?

2.Would it be safer to remove the boards altogether,and would the player still function?

3.I have read on this forum about uprated/superior replacements for the TDA1541,namely TDA1541A.Is there anywhere I can get information on the modifications to fit this chip?

Thank's again for the information so far received.

Best regards,
mschwilson

 

[Extreme_Boky]

1. Maybe, but probably not. It looks like the problem is in analog / DAC section and it shouldn’t be that difficult to trace.

2. I don't think it would be possible to isolate suspect board (analog?). I'm not familiar with your CD player.

3. The old TDA1541 might be the problem!!! Symptoms you described would suggest this!!! Definitely try replacing TDA1541 with TDA1541A. Just add 470pF between pins 16 and 17 on A version and…. good luck sourcing this chip….

Regards,
Extreme_Boky

 

[mschwilson]

Hi
I've not done anything just yet as I wanted to get more info(which I now have).
I think that I will use it "as-is" with an outboard DAC,and try to source the "A" chips and do the lot.
Many thank's for all the info,it is much appreciated.
Best regards,
mschwilson

 

[mschwilson]

Hi.
Since my last posting,I have been using the player with an outboard DAC as well as it's own.
The outboard DAC seems to be ok,but I still get whisps of something not quite right.
Here's a thing though,when I used freeze spray on all of the components,it seemed to make no difference to the distortion.
I managed to use about half a can.
The noise is like a faint "tizz",over both chanels,which seems to pulse in sympathy with the music.It gets louder as the volume is turned up,but always just in the background,and it is only there when the disc is playing.
Could it possibly be the laser?(CDM4/11)
Cheers,
Simon.

P.S.How much would a Marantz CD84 fetch ,perfectly working,box and manual.
I may need to sell it to buy parts for the CD2(I've been told "your not buying anything else till you get rid of some stuff).
?