Screen Size And Screen Position Failure; Horizontal Size Failure - NEC DPro2070SB Service Manual

3.2

.4 Screen Size and Screen Position Failure

3.2.4.1 Horizontal Size Failure

Check the voltage at Pin 9 of IC5C0.
NG
OK
Check the waveform at the gate of Q5F1.
NG
OK
T550 or the horizontal deflection circuit (See Item 3.4.2)
Examine the duty factor of the voltage waveform observed at Pin 9 of IC5C0 on the
MAIN PWB and confirm whether it is changed by the adjustment of horizontal size.
IC5C0 on the MAIN PWB or peripheral circuits
Measure the waveform at the gate of Q5F1 on the MAIN PWB.
(Approx. 10Vp-p)
Q5F0, Q5F1 or Q550 on the MAIN PWB, or peripheral circuits
Expected failure point
Expected failure point
Expected failure point
3-7
Horizontal
period