The CD player has always worked fine until recently. It has static noise in the left channel with both RCA and XLR output. There's still music playing in both channels (same volume). The CD player was fully recapped 2 years ago. Could a worn laser effect one channel?Any idea what might cause this?
Why did you replaced the capacitors in this cd player?
Why did you replaced the capacitors in this cd player? The most probably is some Op-Amp or the DAC TDA1547 associated to the faulty channel.
It should not be difficult to find this fault.
Why did you replaced the capacitors in this cd player? The most probably is some Op-Amp or the DAC TDA1547 associated to the faulty channel.
It should not be difficult to find this fault.
The caps were replaced as they were past there best after 30 years. Would an opamp just stop working, or a DAC chip for that matter?
Is the problem 100% only on one channel?
The DRAM chip is quite a common failure item on all these Philips based players and causes loud 'static' or hash type noise but I think it's usually on both channels. If the digital output is OK then I think that would rule out the DAC chip.
The DRAM chip is quite a common failure item on all these Philips based players and causes loud 'static' or hash type noise but I think it's usually on both channels. If the digital output is OK then I think that would rule out the DAC chip.
Hi Mooly, For the moment it is only in one channel. It happened a couple of weeks for the first time, but now it's back. (at the time I thought it was perhaps the XLR interlink and swapped to RCA. Now it's back.)
Are you able to try the digital output into a DAC or Minidisc or similar to see if the noise is on there.
If it is a bit intermittent (and not physical... give the board a good poke and prod) then a tiny amount of freezer dripped onto the chips might help prove something. You can use an air duster can held upside down.
If it is a bit intermittent (and not physical... give the board a good poke and prod) then a tiny amount of freezer dripped onto the chips might help prove something. You can use an air duster can held upside down.
Sorry guys for my belated response. Which chip is actually the DRAM? Could it also be the relay by any chance? The intermittent noise seems to have gotten worse. Still have to go into my storage unit to get to my DAC and spare CD10 to swap DAC boards.
I wouldn't have thought relay related but those things are easy to prove, just short it out if you have doubts.
Have a read at this thread.
https://www.diyaudio.com/community/threads/cd-player-with-distortion-laser.171326/post-2268053
https://www.diyaudio.com/community/threads/cd-player-with-distortion-laser.171326/post-2268642
Have a read at this thread.
https://www.diyaudio.com/community/threads/cd-player-with-distortion-laser.171326/post-2268053
https://www.diyaudio.com/community/threads/cd-player-with-distortion-laser.171326/post-2268642
Hi Mooly, the digital outputs of the CD player are working (actually better than than an Accuphase DP450 it's connected to).
I've resoldering/ checked everything, but no fix. Perhaps one of the opamp got damaged due to static electricity in my apartment? (I'm zapping everything I touch)
Static is normally only a problem to parts that are not fitted into a circuit such as parts stored loose in a drawer or box.
It's difficult to say without actually hearing it but I would doubt an opamp tbh. You might be getting into scope territory to look at what is going on.
It should be possible to 'cross couple' the outputs from the DAC so that you effectively swap the left and right analogue sections. That Instantly proves if the fault is before or after the DAC.
Beyond that the two SAA7321 DAC chips might be worth swapping although easier said than done for an SMD outline.
It's difficult to say without actually hearing it but I would doubt an opamp tbh. You might be getting into scope territory to look at what is going on.
It should be possible to 'cross couple' the outputs from the DAC so that you effectively swap the left and right analogue sections. That Instantly proves if the fault is before or after the DAC.
Beyond that the two SAA7321 DAC chips might be worth swapping although easier said than done for an SMD outline.
This one has the DAC7 that I could switch. Will try to find my CD10 to swap DAC boards