high pressure, screen grid and focus voltages, the transformer provides 180V video amplifier voltage by
winding 2. VD411, C411, R412, VD412, R414 and C412 form the X ray protection circuit. R233, C231, R232,
R403 and C408 form the beam restriction circuit. The winding 9 of the transformer provides CRT filament
voltage.
(5) Field sync and output circuit
Field sync seperator produces field sync signals from compound sync signals and activates the field frequency
splitting system. When a certain number field sync pulse is detected, the field frequency spliting system will
start operation for frequency spliting of the muliple line frequency signals generated by the line frequency
oscilator. The field pulse gained from frequency spliting will be sent to field sawtooth generator for sawtooth
waves, and then transmitted by pin 23. The output circuit of this TV set is mainly comprised of LA7840 and
other components.
(6) CRT output circuit
The tricolor signals produced by LA76814 will be transmitted to CRT board and then to the cathode of the TV
tube after being amplified by videoamplifier which is comprised of V902, V912 and V922.
(7) CCD performance
The CVBS signals produced by LA76814 pin 40 will be amplified and sent to N701 pin 19 via V821 and then
processed by software and hardware inside CPU. The decoded CCD signales will be transmitted to LA76814
pin 14, 15 and 16 via CPU pin 22, 23 and 24.
(8) V-CHIP performance
Performance of V-CHIP is mainly completed by CPU. The CPU receives grade signals from the IC bus and
executes relative performances and shields those programs of relative grade.
4. Electric diagram (see attached page)
IV. Integrated circuit reference
1. All integrated circuit voltages
Following voltage data is achieved while the TV set is turned on, and the electric resistance is achieved when
the TV set is turned off. When the status changes, the data should also be changed. So these data are used as
references.
Circuit Explanation