ViewSonic E771-4 Service Manual page 17

ViewSonic Corporation E771-4
4. The RGB cathodes cut off are adjusted by VR961, VR901 and VR931.
5. Under override condition, "CHECK SIGNAL" will show on the screen.
4-6 OSD (On Screen Display) Circuit
1. The 1502 HTV021-02is OSD IC. The OSD signals are worked by positive vertical pulse from 1701 pin 32
that goes through R521 to 1502 pin 10, and positive horizontal pulse from HFLB1 through R513 to 1502
pin 5. CPU 1701 pin 27, 28 (РС bus) transfers information to 1502 pin 7, 8.
2. The OSD R. С. B signals and blanking signal are terminated at 1502 pin 15,4 14, 13, and 12 to 1501 pin 2,
3,4, and 1, then the OSD picture appears.
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