Installation guide

Aftermarket LCD Upgrade Manual
8 P/N 400-283-301 Rev A
3) Problems you might ignore on the old CRT like a minor flicker in the display will
become quite annoying with the LCD. The barely noticeable twitch becomes a two-
second blink if you don’t clean up the signal.
Putting a new windshield in your car gives you a clearer view but it doesn’t stop the wheel
shimmy or the engine from burning oil. Be prepared to diagnose and repair the problems
that become magnified by the new display.
Some things to check:
Number one on the list is GROUND connections. Connecting the monitor overhead to the
building frame or the electrical conduit isn’t acceptable. It will probably make things worse.
The same goes for the scoring chassis/computer on the curtain wall. Both pieces of the
system, overhead and curtain-wall, must be at the SAME GROUND POTENTIAL! Just running
a protective earth ground to both pieces of equipment doesn’t work, unless they tie
together in the same panel. The display and scoring computer must be physically
connected to the same ground with direct wires from the same ground terminal in the same
panel. Any voltage difference between the overhead ground and the curtain-wall ground
will cause current to flow in the video cabling. This is the number one source of display
problems.
If the two systems are wired from separate panel boxes (or not supplied with the required
isolated ground), run a heavy, #12 AWG minimum wire from the overhead frame directly to
the scoring chassis. Make sure the connection isn’t insulated by paint.
Check the routing of the video cable that runs from the curtain-wall to the overhead. While
these are shielded cables, the shielding is only about 80% effective. Make sure the cables
are routed far away from fluorescent lights, motors and solenoids at the machines and any
other source of electrical noise. When these cables pick up electrical interference, CRT
displays just show some noise in the picture while LCD monitors will probably blink off and
back on.
Check the AC wiring to the overhead assembly. Neutral (the white or blue wire) is NOT THE
SAME as the protective earth ground (the green or green/yellow wire). They are not
interchangeable; they should NEVER CONNECT TOGETHER except at the first power entry
panel. For North American plugs or receptacles, the neutral wire goes to the wide slot or
prong and the protective earth goes to the long, rounded pin. Don’t get them reversed.
Lamps and fans may work but the scoring will have problems.
Older electrical systems often used the conduit or building frame for the protective ground.
This isn’t acceptable for scoring systems. Properly installed scoring power will have a green
(or green/yellow) wire from the isolated ground screw on the outlet that powers the
overhead (you do have IG outlets don’t you?) to the isolated ground bus in the scoring