Corner Purity Compensation Circuit Failure - NEC DPro2070SB Service Manual

3.4.7 Corner Purity Compensation Circuit Failure

Adjust the corner purity by OSM control.
NG
Confirm that the voltage at Pins 49 (TR), 50 (TL), 51 (BR) and 52 (BL)
of IC102 on the MAIN PWB are variable by OSM control.
NG
OK
(TR): Confirm that the output voltage at Pin 8 of IC803 is variable by OSM control.
(TL): Confirm that the output voltage at Pin 2 of IC803 is variable by OSM control.
(BR): Confirm that the output voltage at Pin 8 of IC801 is variable by OSM control.
(TL): Confirm that the output voltage at Pin 2 of IC801 is variable by OSM control.
NG
OK
1) (TR): The corner purity coil of Pin 2 of CN801
2) (TL): The corner purity coil of Pin 4 of CN801
3) (BR): The corner purity coil of Pin 6 of CN801
4) (BL): The corner purity coil of Pin 8 of CN801
Expected failure point
IC102
Expected failure point
IC801 or IC803
Expected failure point
OK
Good
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