Prima PH50D8, Руководство по обслуживанию

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Among which:video decoder:VPC3230 Non-interlace conversion:PW1230
Ad conversion and DVI interface :AD9887 Audio treatment:MSP3440
Sound power amplification:D type power amplification of TI : Tpa3001
3D Y/C separation:uPD64083
CCD/V-CHIPdecoder:Z86229
（ For North America only ）
Below is a short introduction to the basic work process flow of model PS-42D8series:
This TV model is based on dual MCU control of which the main MCU is PW181
（
N501, taking care
of the operation of various chips (including image treatment, channel switching, image display etc.), infra
red remote control receiving, the standby control, the control of auxiliary CPU, menu display, debugging
of picture effects and other major functions. The auxiliary CPU is SDA555X
（ NM5, which is responsible
for sound treatment (including volume adjustment, control of alt and base sound, stereo decode), station
searching control, push button, separation of 3D Y/C (valid only for system N) as well as the
CCD/V-CHIP decoding for the text for oversea sale TV sets etc. Connection between two MCU is made
by means of three pins of X708, i.e., INT (interruption), S1(RXD), S2
（
TXD
）
2.Volume of sound
This model employs double integrated tuner (including high frequency and medium amplification
circuits). The signal received by antenna is fed to the main tuner, TUNER1, which contains a high
frequency distributor, from which RF signal is shunt to supply to TUNER3 for use. Pin 14 of TUNER1
is for the power supply of high frequency distributor (+5v). Tuners are controlled by auxiliary MCU
NM5
（
SDA
、
SCL
）
to select proper channel and carry out correct switching of systems. After high
amplification and medium amplification decoding, video signal and audio signal are output. The
output signal of TUNER1 is fed into decoder N102 as the display of main picture whereas the output
signal of TUNER3 is fed into decoder N302 as the display of the auxiliary picture for dual picture.
Audio signal is directly fed into audio frequency processor NM2 MSP3440. At the same time dual
way tuners all send their medium frequency signal of the second sound to NM2 for treatment (used
for decoding of stereo or automatic sound volume control). NM2 is provided with the switching over
device for audio frequency channels. Audio input of VGA/DVI/YprPb of the main board, after the
switching-over as selected by N3, is fed together with the audio signal of TV and AV into NM2, where
switching over is selected. The selected audio frequency signal is made use of in the following three
ways. One way is, after being subjected to the control of volume and alt and base sound, fed
separately through left and right sound channels into sound power amplifier TPA3001 for
amplification. Then it is fed into the loudspeaker for sound reproduction. Another way is also fed
separately through left and right sound channels into earphone power amplifier NM9 TDA7053 for
amplification before being output to earphone socket for listening, of which the volume is controlled
by PWM signal produced by pin 50 of NM5.
The remaining way is output through video board as AV out..
The block diagram of MSP3440 is as follows: