Parker TC1475, Service Manual

Page: 18 / 28

TC1475 / TC2175 / TF2139
17
Circuit Analysis
12.3. Sound processing
：
The SIF2, come from inner phase lock demodulate of TMPA8873-XXXX,
turned into audio signal after limiting amplifier and frequency discriminator.
Two audio signal, out of pin28 & pin29 of TMPA8873-XXXX, enter pin9 of
N681 & N691 separated and audio power amplified. They are used to driver
speakers separated after output from pin16 of N681 & N691.
12.4
.
Periphery AV input processing
：
Periphery AV1
（
V1
、
L1
、
R1
）
input from pin5
、
pin 12
、
pin 2 of N801
（
TC4053
）
separated. Periphery AV2
（
V2
、
L2
、
R2
）
input from pin3
、
pin
13
、
pin1 of N801
（
TC4053
）
separated. The level output from pin56 of
N103 control the switch of N801. The video signal, output from pin4 of
N801, transmitted to inner of TMPA8873-XXXX by pin24 of N103 after swit-
ched. The audio signal, output from pin14 & pin15 of N801, transmitted to
inner of TMPA8873-XXXX by pin24 of N103.
12. 5
.
Line scan
：
Inner synchronize separate included in TMPA8873-XXXX, build up by VCO
surge circuit, line frequency divider, AFC circuit, line output driver. Line
driver signal output from pin13 of TMPA8873-XXX, amplified by V431
(2SC2383) at line-excited level and then amplified by V432 at line output
level.
T471 is the FBT. Volts d.c. +110V
（
21”
）
+135V
（
29”
）
enter it through
pin4. Line flyback pulse divided into two routes: one for heater (virtual value
6.3V) and one for FBP of AFC after through R405 and stabilized voltage by
VD408 (9.1V). Pulse output from pin10 of T471 rectified by VD447 and filter
by C447 and we get +180V for Pre-Amp as power supply. Pin9 of FBT is
ABL , used as input of pin27 of TMPA8873-XXXX.
12.6. Field scan
：
Field output level buildup by CD78040/LA78041(N451) and its periphery
components.
Field synchronization signal enter into saw wave produce circuit after
synchronization separate. Pin16 of TMPA8873-XXXX output field saw wave
driver signal to pin1 of CD78040/LA78041by pass R451, and it is output
from pin5 after driver amplified and output power amplified at the inner of
CD78040/LA78041(N451). C450
、
R454
、
R453
、
R461A/B are field
feedback components for improving filed linearity and stabilizing the field