JVC MX-J30 - Page 47

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 RF output
1.140.15Vp-p?
Replace
it.
MX-J30/MX-J330/MX-J35R
Replacement of laser pickup
Turn off the power switch and,disconnect the
power cord from the ac outlet.
Rep
lace 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 TP1.
(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
is
adjusted
while
the
pickup
is
functioning
normally,the
laser
pickup
may
be
damaged
due to excessive current.
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