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1_ASERD•SC REPA•R:
PART 1: BHDRT DF ACTUAL REPAIR
"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
w/11 do the most good." - Bill Turner
BY BILL TURNER, CUSTOMER SERVICE MGR., ELECTRO-SPORT, INC., COSTA MESA, CA
Our 6-part series begins with "Short of
Actual Repair". This will cover the most
frequent problems with disc players, and
gives maintenance information applicable
to all laser games.
Next month, and the remaining 4
months are outlined as follows:
Second, though the disc players can be con-
sidered somewhat rugged, the laser games
cannot be considered even as rugged as the
last generation of fully digital, single circuit
board games. Finally, it is unavoidable that
this new technology is both very expensive,
and wrought with the occasional bug.
MAY - PART 2: THEORY AND SAFETY -
How the disc player works. How the
the Pioneer PR-8210 type disc players
work. General safety information for
working with laser and high voltage
equipment.
Proper and efficient laserdisc player service
will require some minimal tools in which you
may have to invest. The bare essentials are:
JUNE - PART 3: VOIDING YOUR
WARRANTY (OPENING THE DISC
PLAYER) - Disassembly of the Pioneer
PR-8210 type disc players. Inspection of
mechanical components. Inspection of
fuses. General troubleshooting.
JULY- PART 4: ALIGNMENT AND
REPAIR - The most frequent alignment
procedures for the Pioneer PR-821 O
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.
Laserdisc-based games are an exciting,
refreshing new facet to the video game
industry. They also are generally more difficult
to maintain and service than the typical video
game. But, by familiarizing yourself and your
staff with the intricasies of the laserdisc
players, you will grow to find the laser gamef
and their maintenance both challenging anc
rewarding.
There are some basic facts that cannot be
ignored, that cause the laser games to have
unique service requirements. First, the laser
players are sophisticated signal processing
systems, and the average digital game tech-
nician is not going to understand the tech-
nology without spending some time studying.
1 Fast oscilloscope. Forfull discplayerservice,
you'll need dual trace, delay, and about
60MHz. Plus you'll need to know how to use
it.
Thorough understanding of the NTSC video
waveform. Look at Figure 1. If you don't
understand all the indicated points, crack
the books and learn what's what.
Bunch of the usual digital and television
service hand tools.
Set of the N.A.P. manual #5646. This
manual covers the Magnavox VC 801 O
discplayer, which happens to be almost
identical with the Pioneer PR8210. But
more important, this manual gives some
thorough theory and troubleshooting and
alignment information. Great discplayer
reference.
Another useful tool for disc player service is to
have lots of color television service experience,
or have access to that experience. Both color
TV and laserdisc service require similar under-
standing of the NTSC standard and system
signal processing, and the high-voltage tech-
niques and safety requirements are similar.
While you spend some time gathering the
above exhaustive listing of tools, here are
eight very valuable points to remember, in the
hope that they will reduce the number of
service calls on any laser game.
1 . Never move the disc player while the disc is
spinning. The disc weighs about 4½ ounces,
and spins at 1800 RPM. It doesn't readily
change direction once it's spinning. Simply
shifting the laser game cabinet while the
disc player is active will cause the disc to
scrape against the disc well, spraying plastic
shrapnel throughout the innards, into the
optics and electronics. This of course may
kill the disc player.
Whenever changing or otherwise ac-
cessing the disc, allow a few seconds from
the time you press the reject button before
sliding or otherwise moving the disc player,
to give the disc a chance to brake and slow
down.
2. Keep the lid closed to keep dirt out. Dirt,
dust, and smoke film are the nemesis of the
disc player. It is a sad sight, an objective
lens coated with smoke film, ora disc player
shipped half way around the world for repair
because some small, strategically located
particles of smoke have rendered the focus
section unworkable.
The only excuses for an open lid are
inspection, cleaning, and service.
3. Clean the objective lens every week, or
every 50 to 75 hours. You are a warrior
engaged in battle with tiny smoke particles.
Your weapons are optical cleaning solution
and lens paper, available from a camera
store. Thorough inspection after your victory
is your standing order.
Pioneer recommends cleaning the
objective lens with a 50-50 mix of Freon TF
(DuPont) and ethyl alcohol. Be very careful;
it's a flammable mixture!
4. Clean the disc every week, or every 50 to
75 hours. They used to have laserdisc
commercials on television, showing the
disc being used as a serving tray, complete
with martinis and bean dip. Then the disc
would be inserted into the disc player, and a
perfect picture would ensue. Funny, butthe
bean dip always kills my disc players!
Use a weak solution of ammonia-free
window or glass cleaner, and a soft, lint-free
shammy for cleaning discs. Do not use
Windex as it tends to fog the disc, reducing
the reflectivity.
5. Any time the disc player is moved, the
shipping or set screws must be installed
securely. In the PR 8210 type disc players,
this means saving the shipping screw and
lens plate, and using them during every
move.
Most laser game manufacturers will
void your warranty if you ship a disc player
without the shipping screw. For good reason;
the shipping screw protects a $300 part!
6. Check discs regularly for warpage, and
replace any warped discs. A disc will warp,
much like a record, when exposed to heat.
You should remember that a disc player,
energized but without disc rotation, will
generate sufficient heat within three hours
to warp the disc. Moral: if the disc player
doesn't start, don't leave it on too long.