Checking CD player regulators

[tpatton]

My first recapping of a CD player went badly: at first I had no right channel, but fine digital out.  Then the drawer wouldn't open or shut, but spin fast counterclockwise for five seconds then, with another push, spun more normally clockwise for a second or two, repeating this for more pushes, counter reading eight zeros or two zeros, all repeatable.  I changed to newer belts (this is a Denon 1600, virtually identical to the Denon 1500 II), but that made no difference.

Paul Porcelli, the Turbo DAC maker, suggested to me that I may have blown or burned out a regulator.  This player has five, each with its own heatsink, as usual.  I've measured VDC between the outer (of three) legs of each, and get repeatable results.  But is that the right way to check if they're okay?  I bet someone on this Forum can tell me--and maybe even offer other useful advice.  As usual, I'll be very grateful if so.

[jimbop]

You might want to post your questions here:

http://www.diyaudio.com/forums/digital-source/

[Grainger49]

Tom,

On three pin regulators one leg is input, on output and one is "reference."  Check voltages from the output to ground.  The output leg will be the outer leg with the lower voltage.

I am no help on CD players.  They are  for those guys who work on them often.

[tpatton]

Thanks Jimbop, I'll try the site you suggest.  And thanks Grainger, for your basic info.  I've now done the output (rightmost, as it turns out) leg, and the regulators seem to be okay.  Those with '78' early in their designation (printed on them), and either '5' or '12', have the right positive VDC, namely, either 5 or 12 VDC.  Those with '79' early on have the right negative VDC, 12 VDC for these.  (I learned about the significance of '78' or '79' from a Digi-Key tech while ordering parts for a Hagerman Bugle.)  Too bad the regulators are okay, since I now have to find some other source for a really weird CD player malfunction.  But what is audio life without these challenges?

[2wo]

Well as you just did a recapping, I'd start there. Get a magnifier and a good light and scrutinize around each cap. Look not only at its connection but around it as well. look for a damaged trace, or solder bridge, as well as good joints. If any have metal cans, make sure they don't touch anything there not supposed to. Next carefully check the voltage across each cap, see if what you measure makes sense compared to the voltage rating for the caps you replaced and that no electrolytic caps are in backwards or shorted. Now this is mostly for the power caps, some of the cap are coupling or DC blockers for the audio path and the voltage across them may be hard to predict. but they are in pairs so you can check one against another...John