Abnormal Picture; Raster Brightness Failure; Image Color Failure Or Contrast Failure - NEC DPro2070SB Service Manual

3.2 Abnormal Picture

3.2.1 Raster Brightness Failure

Check the screen voltage
NG
OK
Expected failure point
The video circuit is failure. (See Item 3.4.5)

3.2.2. Image Color Failure or Contrast Failure

Check the video signal input.
NG
OK
Expected failure point
The video circuit (See Item 3.4.5)
Measure the voltage at CN201 on the CRT PWB.
.
Usually the screen voltage is 600 to 800V
T701 (FBT), CRT socket or screen leads
Measure the voltage at Pins 1(R), 2(G) and 3(B) of CN215 and CN216 on the VIDEO
PWB.
Usually, the video input signal is maintained at 0.7Vp-p.
Expected failure point
Signal cable
Expected failure point
3-4