Star Tech Journal

S * T J FEBRUARY 198212
American
Arcade
Technical
Academy
* In-depth instruc-
*
*
*
*
*
tions on solid state
game equipment
Concise 6-day
course, including
text books and
technical manuals
Beginners course:
Second Monday
of each month.
Advanced course:
Fourth Monday
of each month.
Videolecture
series home study
program.
Newly expanded
lecture staff
headed by Don
Wright, former
service repre-
sentative for 2
maJor
manufacturers.
4688 Alvarado Canyon Rd.
San Diego, CA 92120
Call now for infonnatlon:
(714) 287-4263
(In California)
(800) 854-2521
(Nationwide)
Credit cards accepted.
CINEMATRONICS
SYMPTOMS* AND* SOLUTIONS
Blowing of Circuit Breakers
A common failure of the current amplifier, especially in the earlier monitors, is
blowing of circuit breakers CBI and CB2 accompanied by burning of the 47ohm
resistors around the power transistor molex. These transistors are mounted to the
heat sinks which are attached to the metal side panels of the monitor.
If this problem should occur, check for cold solder joints around the molex
pins. Check the power transistors Qll0 and Qlll (vertical) and Q210 and Q211
(horizontal) with an ohmeter or transistor tester to verify that the power transistors
are operational. The best way to accomplish this is by disconnecting the molex
plug and checking directly on the pins. The row of pins with the lone male pin
always indicates the 2N5878 drivers Ql IQ-and Q210. The row of all female pins
indicates the 2N5876 power drivers Ql 11 and Q21 l. Check the drivers on the
display board Ql08 and Q109 (vertical) and Q208 and Q209 (horizontal) with an
ohmeter or in-circuit transistor tester. Upgrade the 47ohm resistors from¼ watt to
½ watt if not so equipped. IMPORTANT: Never operate the game with these
power transistors unplugged or the same resistors will be overdriven and
eventually bum.
No Brightness Control
Should the problem ever arise in a Cinematronics monitor where the intensity
cannot be controlled, check the intensity potentiometer (Rl 1) for an open wiper,
an internal short, or change of value due to heat dissipation in the cabinet. When
checking the Rl 1 for its proper value with your ohmeter it should read between
9.SK ohms and IO.SK ohms end to end. Check for cold solder connections to RI I.
On earlier monitors check for an open 1 0MF capacitor (C 17) on the display
board. On the later model monitors check P.T.K. or Keltron high voltage supply,
whichever one your monitor may be equipped with, as this capacitor is now
incorporated into the circuitry in this unit.
Coin Counter Inoperative
If the coin counter on one of Cinematronics' machines becomes inoperative, check
transistor Q 1 (2N6292) on logic board with an ohmeter or transistor checker. This
transistor is the coin counter driver.
Disconnect coin counter molex and measure DC voltage on red wire. Meter
should read +25 volts DC.
Check molex connector JI to logic board for +5 volts and proper ground.
Check for proper electrical connection at pin 3 of J 1.
No Audio Sound
If one of Cinematronics' games has no audio, the first thing to check for would be
an open speaker coil. If the speaker is good, check 2N6292 and 2N6107 located
on the audio board with an ohmeter or transistor tester. If one or both of these
transistors test bad, replace defective components and also the TL0S l ( operational
amplifier) which feeds them. Check for an open wiper on audio h9ard volume
control. Also, verify the logic board is fully operational. The LS259 (audio
enable) located at F-2 on the logic board would be a prime suspect.