You will need to sit the unit on a very flat surface so you have access to the pickup adjusting screws on the bottom of the chassis.
To start with turn the unit on without any disc in the tray..
Press ( on front panel) PLAY and OPEN/CLOSE, while holding these buttons press the SKIP FORWARD button, hold this until INITIALIZE falshes on the display.
Power off the unit , Power on the unit.. with NO disc in the tray press
( front panel) PLAY and OPEN/CLOSE , while holding these buttons press "5" on the REMOTE CONTROL..
The display should now read "JIT......" after JIT there will be a value, adjust the tracking screw to try and achieve a value of approx 175-180.
Be VERY CAREFULL when making adjustments, it only takes a VERY SMALL amount of adjustment to effect the values.
Keep trying to adjust the value until the unit will read a DVD.
Once you get it to read a DVD do as follows..
Press ( front panel) PLAY and OPEN/CLOSE , hold these buttons and press the "5" on the REMOTE control...JIT should appear on the display.
As the DVD plays , adjust the JIT till it reaches a value of between 080-088.
Hopefully this should work , it takes a little time to adjust but i have resurrected a few units this way.....if you get out to sequence , just follow the steps to re-Initialize the unit and start again..