Maintenance Of Laser Pickup; Replacement Of Laser Pickup - JVC MX-KA7 Series Service Manual

Maintenance of laser pickup

(1) Cleaning the pick up lens
Before you replace the pick up, please try to clean
the lens with a alcohol soaked cotton swab.
(2) Life of the laser diode
When the life of the laser diode has expired, the
following symptoms will appear.
1. The level of RF output (EFM output : ampli tude of
eye pattern) will below.
Is the level of
RFOUT under
0.48V 0.1Vp-p?
YES
O.K
(3) Semi-fixed resistor on the APC PC board
The semi-fixed resistor on the APC printed circuit board which is attached to the pickup is used to adjust the
laser power.Since this adjustment should be performed to match the characteristics of the whole optical
block, do not touch the semi-fixed resistor.
If the laser power is lower than the specified value, the laser diode is almost worn out, and the laser pickup
should be replaced.
If the semi-fixed resistor would be adjusted when the pickup operates normally, the laser pickup may be
damaged due to excessive current.
NO
Replace it.

Replacement of laser pickup

Turn off the power switch and,disconnect the
power cord from the AC OUTLET.
Replace the pickup with a normal one.(Refer
to "Pickup Removal" on the previous page)
Plug the power cord in,and turn the power on.
At this time,check that the laser emits for
about 3seconds and the objective lens moves
up and down.
Note: Do not observe the laser beam directly.
Play a disc.
Check the eye-pattern at
Finish.
MX-KA7
Pin 5 of IC 611
1-21