XOCECO LC27K6, Руководство по обслуживанию

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No sound Check if the “mute” audio frequency setting is selected.
Check if the sound volume is set to minimum.
Make sure the earphone is not connected.
Check if the cable connection is loose.
When playing VHS picture search tape,
there are lines at the top or bottom of
the picture. When being played or in pause VHS picture search tape sometimes
can’t provide stable picture, which may lead to incorrect display of the
liquid crystal TVIn this case please press “auto” key on the remote
control so as to enable the liquid crystal TV set to recheck the signal
and then to display correct picture signal
Principle analysis of LC-27K6
For the working principle of LC-27K6 please refer to LC-27K6 block diagram of the complete TV set.
Following is a short description of the signal flow:
RF signal through an integral tuner TUNER201 produces complete color TV signal which is input,
together with AV1/SVHS(SVHS in priority) and AV2 video signals, into U29 VPC3230D for conversion
selection and decoding. Except for being decoded the selected video signal is divided in two routes: one
is fed to AV output terminal and another route of signal to special 21 line decoder U32 Z86229 of
CCD/V-CHIP for decoding. After decoding by U32, the signal is sent back to U29 with R,G,B,FB format
and superimposed to the original picture decoded, then sent to U13 FLI2310 in ITU-R656 of 8B1T
format for progressive line processing.
YPbPr signal, after analog to digital conversion by U30 MST9883 into YUV with 24BIT is also sent
to FLI2310.
Above two routes of signal are processed by FLI2310 for matrix, color density and tint and then
output as RGB with 24 BIT into the main processor chip U12 JAG-ASM. There are other two routes of
signals: one route is RGB signal of VGA for computer, another route is DV1 into RGB signal with 24 bit to
U12 through interface of U15 TFP403/501. Three routes of signal are processed in U12 for picture
format. Among them, one route of VGA after A/D conversion for RGB is subject to selection for
conversion, together with other two routes, and then processed for digital display including OSD AND
GAMMA correction, and brightness and contrast processing and changed into 1024*768 format. The
RGB signal with 24BIT is output to the LVDS converter, U31 DS90C383A, for conversion into the
signal format which the screen can accept, that is, three pairs of low voltage differential signal and one
pair of time signal. And they are further sent to LCD screen for picture display. The PWM of U12 is also
used to control the brightness of the background light.
The second sound IF signal SIF output from tuner is sent to sound frequency processor N201
MSP3420; the sound frequency signal of YPRPB,and DVI is also sent to N201 after switching over and
selection by switch U34 HEF4052. The AV1/SVHS,AV2 and VGA audio signal are also sent to N201
respectively, where the second sound IF SIF is first demodulated to the audio signal which, together with
four way audio signal, is selected for conversion, and then further sound magnitude controlled and
sound effect treated. The output of left and right signal R/L is divided into two routes: one is sent to SRS
sound field processor N203 M62494 for SRS surrounding sound processing, and further used to drive
the speaker after the D-type sound power amplification N207 LX1722 and amplification of
N205,N206,N208,N210 SI4532DY; the other route is used to drive earphone after power amplification
N212 TLE2142.
Power is supplied from power adapter and then converted into the power required by various
channels and circuits.