Touchmaster
®
Conversion Kit
Troubleshooting - 13
2. Verify that the CPU Board Assembly is correct for
this VGM. Each CPU Board is marked with the
manufacturer name, assembly number and the
hardware version.
Wrong ROM
1. Verify that the ROM instruction set is correct for this
VGM. There is more than one ROM in a VGM set.
Each ROM circuit is labeled with the assembly
number and the software version.
2. Turn ON VGM power.
3. Using the 20 Volt DC range on a digital voltmeter,
measure DC voltages at Power connector pins.
4. Refer to Typical Cabinet Wiring Diagram for
specific wiring information and voltage limits.
5. Adjust the +5V source if it is variable.
6. Using the 2 Volt AC range on a digital voltmeter,
measure the same DC voltages as above. Any
reading indicates that the supply voltages are
unstable and may contain ripple or noise.
7. Compare CPU Board Light Emitting Diode states
with the LED Indicator Status Chart.
•
Monitor does not
lock onto signal and
provide a stable
picture.
•
Colors are missing,
etc.
Poor connection
Check connectors and cables for wiring continuity from
the CPU Board Assembly to the Video Monitor.
Wrong
board
assembly
1. Ensure that the CPU Board Assembly is correct for
this VGM. Monitors for some VGMs require
different sync polarity than Midway production units.
Units with incorrect polarity or unusual sync
connections will result in what appears to be
horizontal tearing or complete loss of sync.
2. Verify that the Video Monitor is operating correctly
by placing it in a known functional unit
•
VGM operates
normally.
•
Video wavers or
rolls, has dark bars,
uneven colors, etc.
Poor connection
1. Check connectors and cables for wiring continuity
from the CPU Board to the Video Monitor.
2. Ensure that all the cabinet ground wires are
connected, especially at the Video Monitor Chassis.
Interference
1. Move the cabinet away from machines, appliances,
other VGMs, etc. Some equipment normally emits
very strong electrical or magnetic fields.
2. Verify that the Video Monitor is operating correctly
by placing it in a known functional unit.
