JVC player suddenly plays only some discs. | Error Codes ?

[Seeker47]

I've been visiting someone who has a JVC XV-S500 player -- about 2 or 3 years old --
that has always given very good performance. Just the other day, it began barfing
on all commercial-release DVDs. It goes from a looong "Now Reading" to an
an eventual "No Disc". The LED bar on the face of the player displays "S4", which may
be some kind of error code. (There is no reference to this in the player manual.)

Curiously enough, the player still plays about half of the sample discs I've made on a
computer, and most of the sample discs I've recorded on a Pioneer DVDR. This would
seem to be the opposite of the failure mode one would expect to see.

I'd imagine the first advice I'm going to get is to chuck that player and put in a new one.
I'll probably wind up doing that for them. Unfortunately, the setups here involve home
entertainment center furniture with very tight spacing, where it is rather difficult to gain
access to the components.

I would be curious to know if this type of failure means something to any of you. Also,
if you happen to know of any reference websites that have good lists of device error
codes. Yeah, I know, "Google is your friend", and I'll do that, but I thought I'd ask here
also.

[victoriabears]

could it be overheated?,,or use a lens cleaning disc.