XOCECO LC-42T17, Service Manual

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table 2, check the picture and sound.
Table 2 Component format signal
No. H-frequency(kHz) V-frequency(Hz) signal
1 15.735 60 SDTV 480i
2 15.625 50 SDTV 576i
3 31.47 60 SDTV 483p
4 45.00 60 HDTV 720p
5 33.75 60 HDTV 1080i
6 28.13 50 HDTV 1080i
7 67.50 60 HDTV 1080p
8 56.25 50 HDTV 1080p
4.5 HDMI terminal
Input the DHMI signal source (VG849 signal generator), separate input format signal in table of
table 3, check the picture and sound.
Table 3 HDMI format signal
No. H-frequency(kHz) V-frequency(Hz) signal
1 15.735 60 SDTV 480i
2 15.625 50 SDTV 576i
3 31.47 60 SDTV 483p
4 45.00 60 HDTV 720p
5 33.75 60 HDTV 1080i
6 28.13 50 HDTV 1080i
HDMI format signal of audio
channel 2
sampling rate support 32Kbit/s 44.1Kbit/s 48Kbit/s
bit wide support 16bit,20bit,24bit
Working principle analysis of the unit
The unit has two MCU, the main MCU is PW218 (N601): it is used to control all the chips’ working
status on the main board (including image processing, channel switch, sound processing, image
display etc.), sub CPU, OSD, searching channels, image effect adjustment, buttons control, infrared
remote control etc.; the sub CPU is ATMEGA8L (N606): it is used to control power supply, including
standby and turning on the unit by using remote control etc.. The two MCU correlates with each
other through pin 14 INT (interruption) of ATMEGA8L, pin 28 and 29 SDA, SCL.
The unit has one integrative tuner (including HF and IF amp. circuits). The signal received by
antenna is sent to tuner, under the control of MCU PW218 (N601) SDA and SCL, proper channel
selection and right system switching will be done by the tuner, then video signal and audio signal
will be output by the tuner through decoding and by high and intermediate amplification. Video
signal of the tuner will then be sent to Decoder PW2300 (N201). Audio signal of the tuner will then
be sent to AV switch box M52797 (N400), the audio signal of AV1, AV2 and HD2 of the main board
will also be sent to M52797 (N400) at the same time. The selected audio signal after switching will
be sent to R2S15900 (N301), and then switching selection will be done towards the above audio
signal together with the audio signal of VGA, HDMI and HD1. The two chips are controlled by