G1 And Brightness Control Circuit - Kortek KTN-2001 Service Manual

KORTEK Corporation
KTN-2001/1401
When horizontal drive receives output pulse from TDA2595 PIN 4 and supplies it to Q605
base, Q605 repeats on/off motion by pulse and at this time pulse generated at T601
operates T601.
It is composed that if T601 operates, pulse abandoned from the secondary side of T601
can fully drive horizontal output TR. Then it is supplied to Q604 base and repeats on/off
motion by pulse. Thus FBT can be operated. Then pulse to be supplied to horizontal
deflection is generated at C616, C609 and C613 (When Q604 is on, C616, C609 and C613
are charged. When it is off, they are discharged.) for supply and Vcp voltage of
900~1000V is connected to T701 PIN1. This voltage varies according to the supplied
voltage and here supplied voltage is boosted into higher voltage at T701. Then it becomes
output as high voltage, screen voltage, focus voltage and etc.
6-8 G1 & BRIGHTENESS CONTROL CIRCUIT
G1 control connects CDT G1 deeply to blanking section and makes line not to appear on
screen by using the horizontal and vertical blanking pulse. And also this voltage receives
input voltage of FBT PIN 7 and it is composed to control brightness so that voltage is
controlled in the range of –0~-70V.
Q702 is a circuit composed so that line does not appear on screen by turning on of
blanking section only and making complete cut-off through connecting deeper minus
voltage to G1 than back raster level. It is composed of D201, R205, R206, R701, Q701,
Q702, D702, D703, C705 and etc..
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