Optical Pickup Self-Diagnosis And Replacement Procedure; Self-Diagnosis - Panasonic SC-TM72DV Service Manual

How to distinguish Laser destruction/damage
Confirmation 1
Remove cover of mechanism block so that you will see the lens of optical pickup.
Confirm emission of laser at the moment when power switch is turned on.
If there is no laser emission, laser diode is faulty.
Confirmation 2
While press and hold "STOP" on main unit , press "Display" button on the remote controller. Unit display laser current on FL.
From the reading of display, you can judge if laser diode is damaged or not.
Reading on the right side should be less than 70. If reading is more than 70, laser is damaged.
How to confirm if Optical Pickup is OK
Confirmation 1
1. Confirmation of jitter value with test disc. (Refer below for how to check jitter)
2. Lens cleaning.
3. Reconfirm jitter value.
4. Perform tile adjustment. (Refer to tilt adjustment)
5. Reconfirm jitter value. (To confirm jitter value, while pressing "STOP" on main unit and "5" on remote controller.)
Unit display jitter value on FL.
Confirmation 2
If servo is very unstable due to optical error and you cannot confirm jitter value, clean the lens and check appearance of pick
up unit (cutting coil of actuator, etc), then check circuitry.
14 Optical Pickup Self-Diagnosis and Replacement
Procedure

14.1 Self-diagnosis

14.2 Cautions to Be Taken During Replacement of Optical Pickup and Spindle Motor
14.2.1 Cautions to be taken during replacement of optical pickup
14.1 Self-diagnosis
This unit is equipped with the optical pickup self-diagnosis function and the tilt adjustment check function. Follow the procedure
described below during repair in order to perform self-diagnosis and tilt adjustment effectively. Especially when "NODISC" is
displayed, be sure to apply the self-diagnosis function before replacing with an optical pickup.
Replacement of optical pickup generally requires when the present value of laser drive exceeds 45 (DVD) or 45 (CD).
Note:
Start diagnosis within three minutes after turning on the power (as diagnosis fails when the unit becomes warm).