Video Problems

Symptom

Probable Cause

Solution

No picture

Dip switches on the memory

Dip switches 1 and 2 must be 'ON',

board improperly set.

and 3 and 4 must be 'OFF

Bad connections or video

Make sure there are good

inputs are not hooked up

connections from the board's video

properly.

outputs to the monitor's video

inputs.

Monitor

Make sure the monitor is operating

correctly. (Check it with another

compatible logic board.)

JAM MA harness connected

Identify Pin 1 on the JAMMA

improperly

connector and on the PCB. If

installed incorrectly, damage to the

PCB may have occurred.

Scrambled Picture

Missing sync connection or

Check the sync connection - Adjust

misadjusted monitor

monitor.

Monitor out of sync and can not

Need a 75 ohm pull-up resistor

Solder a 75 ohm resistor across D9

be adjusted.

on the sync line.

located on the main board.

Missing colors or a washed out

Bad video connections

Check the video red, green, and

color

blue connections.

Bright, blurry, or rolling picture

Misadjusted monitor

Adjust the monitor, not the board.

(Refer to your monitor manual.)

Picture too large, too small, or

Misadjusted monitor

Adjust the monitor, not the board.

off center

(Refer to your monitor manual.)

Video image is flipped

Misadjusted Monitor

Change Dip Switch 3 on the Main

PC board or reverse the monitor's

convergence wires. (Refer to your

monitor manual.)

Bad images in picture

Bad GROM

Do GROM test. Check IC pins to

make sure none are bent over.

Diagonal white lines

GND problem

Earth and Logic GND's should be

connected at the power supply.

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