Distortion Compensation Circuit Failure; In/Out (Pincushion), Align (Trapezoidal) And Top/Bottom (Corner Correction) Failure; Left/Right (Pincushion Balance), Tilt (Parallelogram), And Top Balance/Bottom; Balance (Corner Correction) Failure - NEC DPro2070SB Service Manual

3.2.6 Distortion Compensation Circuit Failure

3.2.6.1 IN/OUT (pincushion), ALIGN (trapezoidal) and TOP/BOTTOM (corner correction) Failure
Check the voltage at Pin 12 of CN600.
NG
OK
Check the waveform at Pin 9 of IC5C0.
NG
OK
Check the waveform at the gate of Q5F1.
NG
OK
Expected failure point
T550 on the MAIN PWB or peripheral circuits for deflection output

3.2.6.2 LEFT/RIGHT (pincushion balance), TILT (parallelogram), and TOP BALANCE/BOTTOM

BALANCE (corner correction) Failure

Check the voltage at Pin 11 of CN601.
NG
OK
Q501, Q502, Q503, Q504 or T501 on the MAIN PWB, or peripheral circuits

3.2.6.3 ROTATE (raster rotation) Failure

Check voltage at Pin 45 of IC102 of the MAIN PWB.
NG
OK
Check voltage at Pin 1 of IC804.
NG
OK
Expected failure point
CN802 or rotation coil
Check the output waveform at Pin 12 of CN600 on the MAIN PWB.
Confirm that the waveform changes to parabola form when IN/OUT is selected by the OSM.
Confirm that the waveform changes to saw-tooth form when ALIGN is selected by the OSM.
Expected failure point
IC601 on the DEFL_SUB PWB or peripheral circuits
Check the output waveform at Pin 9 of IC5C0 on the MAIN PWB.
Expected failure point
IC5C0 on the MAIN PWB or peripheral circuits
Examine the duty factor of the voltage waveform observed at the gate of Q5F1 on
the MAIN PWB and confirm whether it is changed by the adjustment of OSM.
Q5F0, Q5F1 or Q550 on the MAIN PWB, or peripheral circuits
Examine the voltage waveform observed at Pin 11 of CN601 on the MAIN
PWB and confirm whether its phase is changed by the adjustment of OSM.
Expected failure point
IC601 on the DEFL-SUB PWB or peripheral circuits
Expected failure point
Control the ROTATE with OSM and confirm whether it changes within
the range of 0 to 5V DC at Pin 45 of IC102.
Expected failure point
IC102 or peripheral circuits
Control the ROTATE with OSM and confirm whether it changes
within the range of 0 to 15V DC at Pin 1 of IC804.
Expected failure point
IC804 or peripheral circuits
Expected failure point
3-11