On Monday, 13 June 2016 18:21:11 UTC+1, wrote:
Are you sure the drive motor is good? If it is 'twitching' as you suggest, it just may be bad. I expect it is a Hall Effect motor with the speed fixed by the clock. So, either the motor or the clock should be on your list of suspects. Do you get output to the motor?

This is, after all, a mini-system, and so may not be as rugged or as easily serviced as a stand-alone CD player.

Peter Wieck
Melrose Park, PA

Thanks for the reply. I have replaced the entire CD mechanism and so have replaced the motor. I believe that the sequence is as follows:
1. Laser turns on
2. Focus adjustment
3. Motor will start if focus is OK, PLL is OK and RF output is present.
I have clock (from the chip). Focus is active (lens moves) but I have no RF and the APC of the chip is not going low.
Can happily email schematic and datasheet is it would help.
Regards, Rupert