Hi
Most of the procedures quoted in the manuals can be forgotten, focus,
tracking etc until you get the thing actually playing!
I've done dozens of these over the years and ~EVERY new laser needed its
grating setting correctly
gripe -gripe- here in the UK the lasers cost 3 times most other
manufacturers and never come setup - gripe gripe

the procedure I use is basically as follows:

1 put unit in test mode (press switch/ short contacts whilst powering up).
Also if the pots have been twiddled , mark where they were and then centre
them

2 run sled out to around 2/3 - 3/4 way to expose the grating adjust plate
shuttle button on front

3 turn on laser, focus servo and tracking servo (buttons vary- see manual)

your disc should Ideally spin now whilst noise is heard from the servos. A
scope can then measure the EFM/rf/eye pattern

4 you should have about .75volts p-p

5 CAREFULLY! adjust the grating to get the highest peak output. dont worry
if it goes haywire in between peaks, just keep pressing stop, then resetting
servos on. I say carefully since there are usually 3 points that are
'useable' and if its the laser with the sliding metal plate adjuster it has
a habit of pinging loose when moved to much. once you're happy you're on the
top peak then a bit of judicious setting of the other servos can be
attempted.

Hopefully now when you close the final servo (pause key I think) music
should be heard and if it skips then tracking offset/gain can be adjusted.

It is somewhat of a black magic art difficult to put into words.
Don't forget if its set on the wrong peak it will play but compatibility etc
will be very poor

Good luck
Andrew