ViewSonic P90F Service Manual page 24

Brightness control: Pin 2 of IA01 provides Brightness control. It feed through P903 to base of
Q960 to vary R, G, B bias at cathodes simultaneously.
8-7 Convergence circuit
Pin1 of IA01 provides a voltage (0 to 5V) to Q426, Q427, and Q428, then drive the Horizon.
convergence coil of deflection yoke through P420..
Pin39 of IA01 provides a voltage (0 to 5V) to Q305, Q306, and Q307, then drive the vertical
convergence coil of deflection yoke.
8-8 Purity circuit
PWB-0417 provides purity control on four corners of CDT.
Through IIC bus (pin 27, 28 of IA01), IA01 communicate with I501 on purity board. I501 is a
digital to analog converter. There are four controls on corners of CDT. User can adjust the white
uniformity and color uniformity at four corners.
ViewSonic Corporation
20
Confidential – Do Not Copy
P90f-1