Excess Luminance - DEC VR297 User Manual

12
Troubleshooting

1.2.6 Excess Luminance

START
DISPLAY THE CIRCLE
CROSSHATCH SCREEN
DOES
THE CONTRAST
CONTROL INCREASE AND
DESCREASE THE
IMAGE
DISCONNECT THE THREE VIDEO
INPUT CABLES FROM THE REAR
OF THE MONITOR
IS THE
BACKGROUND
RASTER STILL VISIBLE
ON THE
SCREEN
IS THE
S1 SWITCH
IN THE CENTER
(NORMAL)
POSITION
DOES
ADJUSTING
THE G2 CONTROL
TURN DOWN THE
RASTER
RECONNECT THE VIDEO CABLES
AND PERFORM THE A BOARD
ADJUSTMENTS (2.3)
SECTION NUMBERS ARE IN PARENTHESES.
ADJUST THE CONTRAST CONTROL
TO DETERMINE IF THE
CIRCLE CROSSHATCH IMAGE
VARIES IN BRIGHTNESS
NO CHECK THE +12, 12,
AND +60 VOLT POINTS
ON THE B BOARD
YES
ARE
THE THREE
VOLTAGES WITHIN
TOLERANCE
NO
THE PROBLEM IS NOT
IN THE MONITOR.
REFER TO THE SYSTEM
DOCUMENTATION AND RUN
THE GRAPHIC DIAGNOSTICS
YES
SET THE S1 SWITCH IN
NO THE CENTER POSITION.
SETTING S1 IN ANY OTHER
POSITION DISPLAYS
EXCESSIVE RASTER
YES
NO
REPLACE THE
A BOARD (3.7)
YES
IS THE
RASTER DISPLAY
NORMAL
STOP
NO REPLACE THE
POWER SUPPLY
BOARD (3.4)
YES REPLACE THE
H/J CONTROL
BLOCK (3.12)
NO REPLACE
THE WHOLE
MONITOR
YES