S*TJ JANUARY 1982 13
ADJUSTING THE
ATARI
MATSUSHITA MONITOR
"THE BOOK"
REVIEWED BY TODD ERICKSON
SUMMIT AMUSEMENT, ST. PAUL, MN
This industry is, to a large degree, a service related industry.
Many operators have bought good equipment, but those who
have the best service are going to be the ones that will excell. As
this industry expands, we need more service people. These
people have to be trained properly. On-the-job training will only
go so far and sometimes reflects the incompetencies of the man
doing the training. "The Book" will not train a person, but it will
start him out with the necessary skills including test equipment.
This includes soldering, meters, and physically working on the
boards. Most of the people working in the field already will have
little use for this particular section. Next, it goes into basic
troubleshooting, including Atari mechanical controls. One
complete section covers monitors. This, to me, has been the most
useful section. I have had very little trouble with "Quadrascan"
monitors. Because of this, I've never had to learn very much
about them. When one finally did need repair, it took only a few
minutes to locate the problem by using "The Book". All the
schematics for the monitors are in "The Book". From there, it
goes into board components, starting with resistors and capa-
citors and going through various digital circuits, including
microprocessors. A complete description of everything covered
in "The Book" would involve more than space permits.
The cost of all of this? Just $39.00. Some people may feel this is
alot of money. With labor and the cost of business as it is today,
one less repair job to the distributor will more than pay for "The
Book". If it saves you a few days over a weekend of down time
for a machine, the $39.00 cost will be made up several times.
There is a registration card inside so that Atari will be-able to
update "The Book" for you. Send it in.
The Matsushita 14-inch color monitor has a crowbar overvoltage
protection circuit that kills the high voltage power supply when the
horizontal hold adjustment is not set properly. The coarse horizontal
hold adjustment is accessible from the front of the monitor through a slot
in the mounting bracket. Use the following procedure to properly adjust
the monitor. Refer to the monitor manual for the position of the controls
and fuse .
1 . Misadjust the coarse horizontal hold until the picture loses sync, or
the picture flips diagonally.
2. Rotate the coarse horizontal hold back slowly until the picture
straightens plus an additional 5 degrees of rotation.
3. Tum the game on and off several times to ensure that the game will
hold the adjustment when it is first powered up.
Another possible cause of the screen blacking out is the B+ supply being
adjusted too high. The 115 volt DC power supply can only be adjusted
when there is a picture on the screen. This is because a load for the power
supply is needed. When the crowbar circuit kills the high voltage, the B+
supply will probably be running at about 170 volts. To properly adjust
the B+ supply, perform the following steps.
1 . Tum the game power off with the AC interlock switch.
2. Set a DC voltmeteron the 250 volt range, and attach the positive lead
to F2 (the small lA fuse near the center of the monitor PCB). Attach the
negative lead to ground.
3. Find R812, the B+ adjustment. Itis accessible through the slot on the
CRT bracket on the front of the monitor.
4. Tum on the game power, and adjust the B+ to 114 volts DC as soon
as you see the screen light up with a picture.
5. Tum the game off and on to ensure that all the monitor adJustments
are properly set. Tum the game off and on again if any horizontal or
vertical adjustments were necessary.
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q EIElctronfo' Joke Box-
□ ··schematic Readirig
□ Circuit Board Repair
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