Star Tech Journal

JUNE 1984
gear niay be broken. The pinion
gear rides on the motor shaft, and
is accessed by removing the two
screws holding the slider motor
bracket in place. The gear is held in
place by a plastic "C" clamp. I use a
fine needlenose to remove and
replace.
The main circuit board, called the
VSOP or Video Servo Panel, is held
down by five screws around the
panel perimeter. By removing these
screws, with the disc player upside
down, the panel can be swung for-
ward for access to the test points.
The test points are the two con-
nectors marked TPs, and notice
that the numbered points are not In
sequence. Extra care is required
during alignment to insure that
you're adjusting the test point you
wanted to adjust.
The Magnavox VC801 O has silk-
screened parts identification on
the solder side of the board. This
allows us to complete full alignment
without folding down the VSOP
panel; just pull the back cover. The
newest Pioneer PR821 Os now
share this feature, and the superior
Spindle Motor mount, but the older
821 Os don't have the silk-screened
VSOP panel and must be folded out
to read the alignment points.
Now is the time to locate all the
variable resistors, marked "VA" on
the circuit board. Just about every
alignment point you need to reach
is on the VSOP circuit board. The
• FIGURE 1 [A. B, CJ: CHASSIS FAMILIARIZATION -
points are shown in Figure 2, al-
though alignment will be covered
next month.
When I receive a disc player for
service, I remove the bottom cover
before I ever energize the unit. I
inspect the slider rail path first. If I
can slide the slider, then I know the
disc player did not have a shipping
screw installed, thus I can anticipate
a broken pinion gear on the slider
motor, and expect other problems
as well. If I cannot move the slider,
PR-B21 D TYPE DISC PLAYERS
A
VHF CONVERTER
SLIDE OPTICS BOX
LASER START TRANSFORMER
LSPS
SLIDE POT