Troubleshooting guide

Cinematronics Vector Monitor Repair Guide v.1.0
Page 43 of 53
Appendix A: Operator's Guide To Troubleshooting
(taken from the Cinematronics Star Castle manual)
O.K. - this is where we get technical on you - but don't panic! We'll keep this as simple as possible
so you can figure out which board to send out for repair. For some of the steps in this section you
will need a simple VOM [multi-meter], and know how to use it.
Here are two important procedures we will refer back to in this section:
Checking the LED:
Whenever there is a problem with the game, a good place to start is the LED (light-emitting diode)
on the CPU board near the Molex power plug. This LED indicates whether most of the CPU
circuit is working. When everything works right, here's what happens: Power to the game is turned
on, the LED flashes on, then stays off. If the LED is flickering or on continuously, there is a
problem with the CPU or the +5 volt supply. Check +5 volts on the logic board (follow procedures
in this section). If the +5 is O.K., have CPU repaired.
Checking the +5 Volt Supply:
To check the +5 volts, you need a voltmeter. Turn power on in the game. Notice on the upper
corner of the logic board nearest you is a little pin marked GND. This is a great place to put the
negative probe of the voltmeter. Near this pin in position T13 (see CPU layout, pg. A-8) is a 20 pin
IC marked 74LS377. Ignore the other numbers on this chip. We can measure the +5 volt supply at
pin 20. Pin 20 is the bottom pin on the far side of the chip. Put your positive probe there, without
touching any other pins, and you should get a reading. Anything between +4.8 volts and +5.1 volts
is ok, otherwise, adjust the voltage.
The adjustment is located on the power supply, and it is the only screwdriver adjustment on the
power supply. Adjust slowly WHILE READING THE VOLTAGE. Too much voltage will
destroy IC’s fast. If voltage cannot be adjusted into the correct range (+4.8 - +5.1 volts), repair
power supply.
The following is a guide compiled from experience. It cannot be right 100% of the time:
Symptom: Circuit breakers trip.
1. Unplug game. Unplug Molex power plug from monitor and reset breakers. Turn POWER ON.
If breakers trip: POWER OFF, see 2.
If breakers don't trip: Coin-up game and "play" it. Are all sound effects normal?
Yes - Repair monitor.
No - Problem is probably in CPU or power supply. Check LED on CPU. Check +5 volts
on CPU (see procedure) If +5 volts is good, repair CPU.
2. Unplug Molex power connector from audio board, reset breakers and turn POWER ON.