Midway 4-Player 25" Dedicated Video Game manual Video Troubleshooting Table

Video Troubleshooting Table

	SYMPTOM	CAUSE		REQUIRED ACTION
				Verify connection of AC Power to video monitor.
•	Monitor appears non-	Power problem		Inspect CRT neck in dim light. Glowing filament
	functional			near CRT base proves that some monitor
				circuits receive power. Still, voltages or signals
•	Audio is present			may not be normal.
			1.	Turn off VGM power. Verify that video signal and
• VGM (video game machine)		Faulty wiring		Remote Adjustment Board connectors seat
	controls operate normally			properly on Video Monitor Board.
			2.	Assure that video cables connect to circuit
				boards.
			3.	Assure that no wires are caught on chassis or
				mounting brackets.
		Improper monitor	1.	Check that BRIGHTNESS (intensity) and
		adjustments		CONTRAST are set above their minimum levels.
			2.	If necessary, adjust these settings.
			1.	Examine AC line fuse on Video Monitor Board. If
		Faulty monitor		fuse is faulty, replace it with identical fuse.
		circuitry	2.	If fuse is good: Verify that video monitor
				operates correctly by placing it in working VGM.
			3.	If monitor is bad: Check monitor power supply.
			4.	If power supply is good: Check monitor
				horizontal output transistor and related circuitry.

WARNING: HIGH VOLTAGE. VGM monitors generate and store potentially lethal high voltages. Avoid touching any part of the monitor until power has been off for some time. A picture tube can maintain a hazardous charge for up to several days. Only qualified technicians should service monitors. Turn off the power, unplug the VGM and discharge the CRT before attempting service. Even properly discharged tubes can revert to a highly charged state, without reapplication of power.

WARNING: In normal operation, the monitor doesn’t require isolation from AC line voltage. During bench servicing, you may need to operate the monitor outside the cabinet. If you do, isolate the monitor from line voltage with an isolation transformer.

CAUTION: Don’t operate the monitor without the Remote Adjustment Board.

Typical Cutaway Rear View

Troubleshooting 6-8