Haier HT-3718 Service Manual page 25

Table 4
No.
1 INT
2 GND
3 EXT
4 SW
5 VOL
6 FL1
7 NFB
8 GND
9 OUT
10 VCC
5). Analysis of horizontal sync and horizontal scan output circuits
As the horizontal oscillation circuit is installed inside N201 (TDA9361), . Some brightness
signals including compound sync signals are transmitted to the internal sync segregation
circuits, where horizontal sync and vertical sync pulses are segregated. C219(472) ,
R235(15K) C220(1u) are connected to N201 (17) are phase-lock loop filters. Horizontal
pumping signals are transmitted from (33) of N201 to horizontal promotion transistor V901
(2SD2383), and then drive the H-DRIVE transformer. After being amplified through it switches
power transistor to control the horizontal scan of the electronic-beam. C918 is a horizontal S
correction capacitor and L901 is for horizontal linear inductor. T902 is a horizontal output
transformer.VD908,R932,R267,R266,C229 are ABL circuits. R930,R931,VD910,C925 consist
of beam-current limit circuit. H-return-trace pulse from pin 4 and pin 3 of horizontal output
transformer T444 via rectification, filt and obtain DC voltage +16.5V and +46V and feedback
to pin 3 and pin6 of N801 for forward and return trace Vertical IC to supply power.
Pin 8 of N801 put out heater voltage 6.3V, pin 6 of N801 supply sync signal for N201 ; pin 9
of N801 put out Horizontal return trace pulse, via rectification, filt and obtain DC +180V for
video amplifying circuit supply power.
6). Analysis of video amplifying circuits
The video amplifying circuits are comprised of N701 (TDA6107Q) and peripheral components.
B, G and R signals output from N201 (51), (52) and (53) go into pin2, pin3, pin1 of N701,
TDA6107Q has 3 video power transistor are available for amplifying the input R, G, B and they
go into cathode of CRT. Pin 5 of N501 is used to check black balance output and checking
signal go into pin 50 of N201 and adjust picture black balance. White balance adjustment is
completed through control of an I
and testing data for TDA6107Q maintenance is listed in Table 6.
Function
2
C serial bus control system. Information introducing functions
25
Working Ground Resistance(R)
Voltage
Positive
V
6.27 54.4K
0 2.6
5.51 54.1K
1.21 86.2K
4.19 20K
9.21 13.5K
9.19 32.5K
0 3
9.25 44K
20 0.4M
Circuit Explanation
Negative
53.3K
0
53.1K
86.6K
20.5K
13.3K
32.3K
1.5
42K
0.4M