I wonder if any one could refer me, preferably with a telephone number, to
someone in the USA who is truly an expert with somewhat older Sony high-end
CD players?

I have a Sony X777ES CD player which was their top-of-the-line CD player in
1991.

This CD player was completely "overhauled" about two years ago by a Sony
Direct Factory Service Center. Unfortunately it is my understanding that
Sony has now disbanded all of their Factory Service Centers.

The Sony X777ES CD player has features that I have been unable to find in
any more up-to-date CD player from any manufacturer, and I like it very
much, even though I am using it with an outboard DAC.

Unfortunately the CD player has refused to recognize or play two recent
Deutsche Gramophone CDs which play perfectly fine in many other CD players,
but at the same time it has no problem reading, and playing, about 300 or so
other CDs.

I have tried to readjust the TRACKING GAIN and the FOCUS GAIN, but changing
either of these did not correct the problem.

I would very much like to have someone repair or readjust my CD player so
that it will indeed recognize, and play, ALL CDs, but I can find no one in
the San Francisco Bay area who is even willing to look at it, and hence I am
wondering if anyone might know a specialist who would be willing to
undertake to correct the problem. I might also mention that I have the
factory service manual for the CD player.

Thank you very much for your consideration.