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

3.2.4.2 Horizontal Position Failure

(1)Video
Check the H_POSI line.
OK
NG
IC601 on the DEFL-SUB PWB or peripheral circuits
(2) Horizontal raster centering (VR5A1) failure
Check the power source voltage for centering.
OK
NG
Expected failure point
T550, D5A1 or D5A2

3.2.4.3 Vertical Size and Position Failure

Check the +15 and -15V lines.
NG
OK
Check the voltage at Pin 15 of CN600.
Check the voltage at Pin 16 of CN600.
OK
NG
IC601 on the DEFL-SUB PWB or peripheral circuits
Confirm that the phase of the voltage waveform at Pin 11 of CN601 on the MAIN PWB
changes when the horizontal position is adjusted with OSM.
Q501, Q502 or Q503 on the MAIN PWB, or peripheral circuits
Expected failure point
Check voltage between C5A1 and C5A2 on the MAIN PWB. Usually, this
voltage is maintained at 5±1V.
L5A1, VR5A1, Q5A1 or Q5A2 on the MAIN PWB, or peripheral circuits
Measure voltage at Pin 1 (-15V) and Pin 6 (+15V) of IC401 on the MAIN PWB.
1) IC401
2) The power circuit, D964 or D965 on the power circuit block
Confirm that the voltage amplitude changes within the range of approx. 2.0 to 3.0 Vp-p
at Pin 15 of CN600 on the MAIN PWB when the vertical size is control with OSM.
Confirm that the voltage amplitude changes within the range of approx. 3.3 to 3.7V at
Pin 16 of CN600 on the MAIN PWB when the vertical position control with OSM.
IC401 on the MAIN PWB or peripheral circuits
Expected failure point
Expected failure point
Expected failure point
Expected failure point
Expected failure point
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