Maintenance of MD pickup
1. Cleaning of pickup lens
(1) Prior to changing the pickup, clean the pickup lens. (2) For cleaning the lens, use the following cotton swab after mearsing it in alcohol. Product No. JCB-B4; Manufacturer;Nippon Cotton Swab
Procedures of changing the MD pickup
Change the MD pickup by referring to "Removing the MD pickup" in the Disassembly method.
2. Confirmation of the service life of laser diode when the service life of the laser diode has been exhausted, the following symptoms will appear.
(1) The RF output (EFM output and eye pattern amplitude) will become lower. (2) The drive current required for light emitting of laser diode will be increased.
Set the pickup to [TEST] mode according to the procedures described in the Adjustment method.
Adjust the laser power 560 W.
Power supply voltage 1.5V
20mV Adjustment
Adjust the disc. Confirm the service life according to the following flow chart: Completion of changing the MD pickup.
Can the laser power adjust under test mode?
NO
Change the pickup
YES
Is the drive current of laser diode 55mA or less?
NO
Change the pickup
Be sure to perform not only adjustment and operation of this system so carefully as not to directly look at the laser beam or touch on the body.
YES
OK.
3. Method of measuring the drive current of laser diode
When the voltage measured at the both side of carbon resistor R301 on the MD servo P.C. board (LVB20008) have become 12.1mV or over, the service life of the laser diode is judged to have been exhausted.
4. About Semi-solid state resistor of pick up
This is adjusted in the maker of pick up . Be careful please not to touch pick up .
