XOCECO LC-19HU56S, Руководство по обслуживанию

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Working principle analysis of the unit
The RF signal received by antenna will be sent to tuner TUN1, then IF signal will be obtained
through high amplifier and mixed frequency, through pre-intermediate amplified by V15, then it will
be sent to SAW filter Z17 to do IF filter and get better IF characteristics, then it will be sent to N3
(TDA4470) to do intermediate amplification, phase-locked loop VCO and synchronous wave
detection to get video signal TV-V; after pre-intermediate amplification IF will also be sent to SAW
filter Z16 to do filter at the same time, then it will be sent to TDA4470 to do intermediate
amplification and output the second sound intermediate frequency signal (TV-SIF).
The TV-V signal output from TDA4470 together with TV-SIF will be sent to main chip
NS2(MST9E19B).
Video signals of AV, VGA and HDMI will be sent to MST9E19B, too.
Video signal of YPbPr and Video RGB of SCART1 via video switch N5 (PI5V330) will be sent to
MST9E19B.
Video signal V (CVBS) of SCART1, YPbPr L/R and SCART1 L/R will be sent to MST9E19B.
The main chip NS2(MST9E19B) is a high performance and fully integrated IC, which can
realize video demodulating, video switch selection, A/D and D/A conversion, interlace/progressive
processing, modes conversion, OSD and low-voltage differential output, etc. And it also has
functions of audio selection, processing and MCU.
The video signal via MST9E19B processing, sends out 4 pairs of differential signal and 1 pair of
clock signal for LCD panel display. TV-V output fromTDA4470 via double video amplifying, it will be
sent to SCART1 for AV-OUT.
Audio signal via MST9E19B processing will be sent to sound amplifier NV12 (TDA7266SA)
amplifying to speaker. TV-SIF via MST9E19B demodulating and sound processing then output to
NV11(LM358D) amplifying, the signal will be sent to SCART1 as AV-OUT.