24
PUMP UP OUTPUT
3
Flyback generator
2.24
∞
GND
4
Ground or negative supply
0.003 0
V.Output 5
Output
13.66 70K
output stage supply
6
Output stage supply
26.7
∞
NOV INV.IN
7
Non-inverting input
2.46 3K
5.Analysis of horizontal sync and horizontal scan output circuits
As the horizontal oscillation circuit is installed inside N201 (TMPA8873PSCNG), .
Some brightness signals including compound sync signals are transmitted to the
internal sync segregation circuits, where horizontal sync and vertical sync pulses are
segregated. Horizontal pumping signals are transmitted from (13) of N201 to
horizontal promotion transistor V431 (2SC2383), and then drive the H-DRIVE
transformer. After being amplified through it switches power transistor V432 (2SC5885)
to control the horizontal scan of the electronic-beam.C412 is a horizontal S correction
capacitor and L407 is for horizontal linear inductor. T401 is a horizontal output
transformer. The horizontal return pulse output from (ABL) of T401 is transmitted to pin
(27) of N201 who controls ABL circuits. ABL avoid high-voltage over rated value that
will cause X-ray and affect your health.
6.Analysis of video amplifying circuits
The video amplifying circuits are comprised of V601, V611, V621 and peripheral
components. R, G and B signals output from N201 (50), (51) and (52), 3 video power
transistor are available for amplifying the input R, G, B. White balance adjustment is
completed through N202 under control of an I
2
C serial bus control system.
7. Maintenance Service and Trouble shooting
A. Principle integrated circuits
A1. 21 INCH color TV set composed of the following sections
(1)
Small signal processing: super monolithic integrated circuits
N201(
TMPA8873PSCNG
). and memory N202 (AT24C16).
(2) Sound power amplifying: integrated circuits N301 (
TDA1517NE
).
(3) Horizontal and Vertical scan output circuits: Vertical output integrated circuits
N401 (
LA78040
), Horizontal output transistor V432 (2SC5885), Horizontal
flying back transformer T401 (JF0501-32806).
(4)
Switch power supply: switch transformer T601 (BCK-08A6S), power IC N601
(FSCQ0765RT)
A2. Main integrated circuits:
(1)
TMPA8873PSCNG
Microprocessor
Picture IF/sound IF/video processing/H and V
Scan/color decoding
(2)
LA78040
Vertical output integrated circuits
(3)
TDA1517NE
Sound power amplifying integrated circuits
Содержание HTR20-A
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