Sanyo LCD-42XR8KH, Service Manual

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6
Working principle analysis of the unit
The RF signal received by antenna will be sent to tuner TUN601, then IF signal will be obtained
through high amplified and mixed frequency. After pre-intermediate amplified by V608, it will be sent
to acoustic surface-wave Z605 to do IF filter and get better IF characteristics, then it will be sent to
N602 (TDA4470) to do intermediate amplification, phase-lock loop VCO and synchronous wave
detection to get the video signal TV-V; after pre-intermediate amplification IF will also be sent to
acoustic surface-wave Z604 to do filter at the same time, the it will be sent to N404 to do
intermediate amplification and output the second sound intermediate frequency signal TV-SIF.
TV-V output from TDA4470 and TV-SIF will be sent to the main IC N304(MST9E89DL)
Video and audio signals of AV/S, VGA, YPbPr will be sent to MST9E89DL too.
3 groups HDMI after PS321 selecting, their video and audio signal will be sent to MST9E89DL.
RGB of SCART1, AV, S-Y and S-C of SCART2 will also be sent to MST9E89DL, their audio
signal and YPbPr, AV/S audio signal via audio switch HEF4052BT selection to MST9E89DL.
The main IC N304(MST9E89DL) is a high performance and fully integrated IC, which can
realize HDMI interface processing, video decoding, video switch selection, A/D and D/A conversion,
interlace/de-interlace 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 MST9E89DL processing, output 4 pairs differential signal and 1 pair clock
signal for LCD panel display. TV-V from TDA4470 after video double amplifying and sent to
SCART1 as AV-OUT. AV processed by MST9E89DL after quadruple amplifying and output as
AV-OUT and SCART2 AV-OUT.
The audio signal via MST9E89DL processing, it will be sent to N206 (BH3547F) amplifying to
earphone. The audio signal will also sent to sound amplifier N203 (TPA3120-D2) amplifying to
speaker. TV-L/R processed by MST9E89DL will be sent to SCART1 for AV-OUT, at the same time,
TV-L/R and AV-L/R will output together as the audio output of AV-OUT and SCART2 AV-OUT.
Wor W king pr ncip ple a a ysis of the unit
T e audio signa gnaal v l via MST T9E89 oo g to ing ify mpl am F) 47F 3354 (B 06 N2 o N t t en e s e s b will g, sing g