Help needed for CD Player issue

[JacquesW]

Hello there! I have an older model NAD C542 cd player that I have changed the optics/ribbon cable and it's back working again. The issue I am seeing is that the temps on the caps and I believe transistors are running at temps over 125*F. I believe they are part of the PS? Is this normal when a disc is being played? Perhaps I should change out these caps and transistors? I was also told that the transformer that NAD uses are running them on +/-25V input on the maximum of the Voltage. If you reduce the Voltage to a lower level then this would run the other parts of the PS at lesser temps! Build in a Voltage Regulator DC/DC and bring the Voltage down to a normal level, then the Regulators are not running so hot!
Any help would be appreciated! Thanks

 

[Gray]

Do you know if those things were running as hot before your repairs Jaques?
Regardless, changing them is unlikely to make them run any cooler.
You could try consulting NAD about transformer voltage - but, as part of the design, that's unlikely to be incorrect, despite what you may have been told.

You could do some confirmatory checks.
DC voltages, where not printed on PCB test points, can be found in the service manual.
Unless they're way out when you (accurately) measure them (too low or too high).....there's not much you can do.

 

[JacquesW]

Do you know if those things were running as hot before your repairs Jaques?
Regardless, changing them is unlikely to make them run any cooler.
You could try consulting NAD about transformer voltage - but, as part of the design, that's unlikely to be incorrect, despite what you may have been told.

You could do some confirmatory checks.
DC voltages, where not printed on PCB test points, can be found in the service manual.
Unless they're way out when you (accurately) measure them (too low or too high).....there's not much you can do.

Hi Gray, thanks for your reply! I just happen to check around the pcb just to see what the various components were running at temperature wise. I just assumed that some of the parts appeared to be higher temps than others. I also noticed a group of small resistors that displayed a temp around 140*F. Perhaps this is ok?

I did check a few of the voltage readings coming from the PS that connects to the board. I did get a few different readings from the various colored wires. I do have the service manual. I tried to upload it here, but it appears that they don't allow a PDF file. Here is the link where I downloaded the service manual:NAD C542 Service Manual

Not sure if you can look at it and perhaps let me know your thoughts. Thanks again for your help!

 

[Gray]

I wasn't able to download it Jacques.
But the diagram should have the important, post- regulated DC voltages.

The PCB layout view might help you to find the test points.
Hopefully you'll be able to confirm that nothing is actually faulty 👍