Trident IS-TVHD30, Service Manual

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10
Working principle analysis of the unit
The unit is digital frequency conversion processing of 16bit bus control color television, it adopt high
integrity digital processing chip EX-11 of TRIDENT, this chip has a A/D conversion, decoder and
scaler. The MCU is 16bit parallel processor M16C of RENESAS.
The unit adopt frequency composition tuner, it can direct display frequency point of every channel.
The decoder chip have digital comb filter, Y/C processing clean separation, chroma signal and
non-crosstalk brightness signal. It adopts three 10bit A/D and D/A conversion to reality of the picture.
The unit working a singles horizontal frequency, it has two YPBPR terminal inputs and support
multi-high definition format (1080i60, 720p, 1080p and so on), it have picture freeze, dynamic digital
code noise reduction, picture edge enhance, PULL-DOWN, 16:9 mode, timing turn off, rotate, CCD
and V-CHIP functions and so on,
The audio processing adopt application specific IC M61519 of MITSUBISHI, it supports stereo,
treble-bass volume control, volume balance, surround sound and over-bass sound functions and so
on. The unit has two AV inputs, an S terminal input, two YCRCB/YPBPR terminal inputs and a video
output.
The RF signal send to compose tuner TUNER101, its pin11 output 38M of IF signal. After the signal
via pre-intermediate frequency amplifier circuit V101, it sends to the picture SAWF Z102 and sound
SAWF Z101, their are contain two filter of single PAL and NTSC, it be controlled high-low level of the
pin 75 of MCU output (the pin59 of main board X701). The Z101 output sends to the pin8 of
N101(LA7566) and Z102 output sends to the pin5 and pin6 of N101. The N101 supports PAL and
NTSC system, it be controlled high-low level of MCU (N707, M16C/30620SPGP) output. The level
define as follow:
System X701-pin55 X701-pin53 X701-pin51 X701-pin49
DK (6.5M) 0 1 1 0
I (6M) 1 0 0 1
BG (5.5M) 1 1 0 1
M(4.5M) 0 0 0 0
Note: 1-high level, 0-low level
The pin13 of tuner output video, the video send to the digital chip N700(EX-11). It have VIDEO, two
AV input, S terminal input and two YCRCB/YPBPR input, it through matching circuit to N700. After it
via bus control and digital processing to pin37, pin39 and pin41 of X701 socket output R, G and B
signal (peak value to 0.8V) and the pin 48 and pin48 output V-SYNC and H-SYNC. The V-SYNC
and H-SYNC send to deflection chip N302(STV9118), the pin26 of N302 output H-signal drive the
V301(2SC5422) and H-deflection coil of picture tube. The pin24 of N302 output EW signal for raster
geometry adjustment. After the R, G and B signal of digital board send to the pin1, pin3 and pin5 of
pre-video amplifier N801(STV9211) form pin14, pin16 and pin18 output to CRT board. The N401 of
CRT board to R,G,B signal amplify to peak value(about 100V), it send to cathode of the picture tube.
The SIF of the SAWF output send to stereo decoder NS01(LA72700), then it output L/R of audio.
The L/R audio of TV, AV/S input and YCRCB/YPBPR input send to sound processor N601(M61519).
Through BUS control of N707 to select processing of N601 signal channel, the pin25 and pin18 of
N601 output L/R audio send to N602 (TA8256BH), the pin8 and pin12 of N602 output L/R audio
drive speaker. In the mute state, the N707 send high level to the pin5 of N602, but the power
amplifier without signal.