Star Tech Journal

I __ ASERDIBC REPAIR:
PART 3: VOIDING VDUR WARRANTY
"My intent with this 6-part series on
laserdisc repair is to get a lot of useful
information into the hands of working
technicians as painlessly as possible.
Therefore I will skip over some of the more
technical matters. This approach is
necessary, I have found, because the
alternative is to require technicians to study
for months before they have the proper
background for disc player repair. Even
without all that theory, there is a lot of good
that can be done, and that's my intent with
this series; to get the information where it
will do the most good." - Bill Turner
BY BILL TURNER, CUSTOMER SERVICE MGR., ELECTRO-SPORT, INC., COSTA MESA, CA
Our 6-part series continues with
"Voiding Your Warranty''. Part 1,
entitled "Short of Actual Repair"
covered the most frequent
problems with disc players, and
gave maintenance information
applicable to all laser games. Part
1 appeared in our April issue.
Part 2, entitled "Theory and
Safety'' covered how the disc
player works. How the Pioneer
PR-821 O type disc players work.
General safety information for
working with laser and high
voltage equipment. Part 2
appeared in our May issue.
Part 3 will cover disassembly
of the Pioneer PR-8210 type disc
players, inspection of mechanical
components, inspection of fuses,
and general troubleshooting.
Next month, and the
remaining 2 months are outlined
as follows:
JULY- PART4: ALIGNMENT
AND REPAIR - The most
frequent alignment
procedures for the Pioneer
PR-8210 type disc players.
The most frequent problems
and their solutions.
AUGUST- PART 5: SOLID
STATE LASERDISC
PLAYERS- General
information on the new
generation of disc players.
Special maintenance and
alignment considerations for
solid state laser head
systems.
SEPTEMBER - PART 6:
COMPUTER-CONTROLLED
LASERDISC PLAYERS-
Covers the Pioneer PR-7820
type disc players. Explains
test and maintenance
considerations, and RS232
conventions.
OPENING THE PRB&10
TYPE LABERDIBC
PLAYER
The PR821 O type disc players are
fairly hefty units, and those who
service them regularly can expect
to acquire impressive biceps. The
work area should afford some pro-
tection against scratching the
plastic case of the disc player. I use
conductive
packing
material
wrapped around a flat sheet of card-
board on a grounded service bench,
and place the disc player atop the
padding for service work. This also
affords the extra advantage of static
protection for the unit. Your cus-
tomers, of course, will only remember
if you fail to provide care for the
disc player case.
Allow plenty of room for your disc
player repair area, as a table full of
oscilloscopes, other test equip-
ment, and scattered disc player
parts can get crowded in a hurry.
Especially if more than one unit is
open at a time, as in comparative
troubleshooting. This technique is
very valuable for technicians per-
forming work on unfamiliar equip-
ment, as signals can be compared
to a known good unit and rapid
performance evaluations made.
You need to understand the layout
of the unit to troubleshoot efficiently,
and you can learn rapidly by opening
a disc player. Remember that most
game manufacturers and disc play-
er manufacturers will not honor
warranty repairs on equipment
worked on by unauthorized persons.
If you proceed, it's your baby.
Lay the disc player on its top and
remove the eight screws that hold
down the disc player bottom cover.
If you orient the unit so that the rear
panel connectors are facing you,
the Figure 1 diagrams will guide
you to the major visible subas-
semblies.
Contact with the laser power supply
and high-voltage wires should be
avoided even when power is off,
because the supply capacitors are
still likely to be energized. When
service to these components is
required, de-energize the supply
capacitors with a high-voltage
shorting stick before removing them.
Notice that the Slider Motor is ac-
cessible even with the VSOP panel
in place. If your disc player is
oriented as above, and you press
the Spindle Motor downward toward
you about¾ inch, you can move the
slider along its rails to inspect the
travel path. Frequently in laser
games we see that cigarette smoke
film or other oils and dirt have made
their way to the slider rails, causing
sticky spots on the rails and Im-
peding the slider path. This can
cause erratic displays on the display.
When this is the case, the slider
should be removed and the rails
cleaned with a gentle solvent,
alcohol for example. Then both rails
and slider should be replaced and
re-aligned in accordance with the
manual, with inspection made to
insure a proper travel path, and
minimal lateral movement of the
slider.
If you find the slider moving without
lifting up on the motor, the pinion