ANSWER: the answer popped into my head. The tracking servo is misadjusted. It is a simple thing you can have it looked at nearer where you live.. any competent tech should be able to re-adjust it.
The CD has a bit of information at the very beginning of the CD. (the track timing, and titles etc. It is ONLY READ ONCE when a CD is loaded. If the CD is repeated, the info is NOT reread. This info with the track timing etc is vital, and a disc will not play if this info cannot be read. From your original posting, when you said the disc will not start, but if it does, and you repeat it will play perfectly over and over until you try a different disc has the answer in the statement.
So that is the problem. My guess is the French dude doing the final checking of your player had a disc repeating and set the servo for the beginning, but did not check it after, and the servo is going back in only barely far enough to 'sometimes' catch the beginning info.
I wish you the best on getting your player fixed.
The CD has a bit of information at the very beginning of the CD. (the track timing, and titles etc. It is ONLY READ ONCE when a CD is loaded. If the CD is repeated, the info is NOT reread. This info with the track timing etc is vital, and a disc will not play if this info cannot be read. From your original posting, when you said the disc will not start, but if it does, and you repeat it will play perfectly over and over until you try a different disc has the answer in the statement.
So that is the problem. My guess is the French dude doing the final checking of your player had a disc repeating and set the servo for the beginning, but did not check it after, and the servo is going back in only barely far enough to 'sometimes' catch the beginning info.
I wish you the best on getting your player fixed.

