After having this player for a while it seems to have developed a issue with digital audio. It seems to get worse the longer I don't use the player and slowly gets better if I use it, but never to the point it's not a problem. (The example below was after a few attempts to record the audio.) and it refuses to play CD's. Analog audio and video playback aren't affected at all.

http://www.mediafire.com/download/8nz63 ... xample.wav
(During playback I switched between the digital and analog tracks. It's fairly apparant which one's which.)

After looking at the waveform while recording, it seems like the player gives up reading the digital track in tiny spurts where there should be some sort of data there, small enough that it never truely blanks but enough to be a problem.
I doubt it's a laser issue if it's otherwise ok with playing things back, so my guess is a issue with the circuitry for digital playback.

It is the RF level being received from the laser, the digital audio is the first to go as the RF level decreases. Either the laser is going or a capacitor in the signal path is going out. I've seen both.

So what would be the best way to diagnose the specific issue one way or the other?

You have to open up the player, put an oscilloscope on the RF test point, play a CD and measure the RF level. Should be 300mV.

Just try cleaning the lens and see what happens

put a Q-tip, doused in Iso Alcohol, to the laser pick-up lens. a couple/three gentle swipes should do it.

with luck, that'll be your problem. otherwise, it could be any number of more complex faults,
or merely a drifted adjustment that needs fine-tuning...