XOCECO LC-37K7 SERVICE MODE AND BLOCK DIAGRAM

XOCECO LC-37K7 

SERVICE MODE AND BLOCK DIAGRAM 

Method for entering factory menu:
press “VOL+”, “MUTE” and “VIDEO” repeatedly to enter factory menu;
Press “ENTER” to select different items when the first line of each adjustment item just lights up; input VGA and DVI signal, then select the “mode” item; after that, you can press “enter” to select three kinds of color temperature namely 6500K, 9300K and 12000K
Press “MENU” to exit.
Note: the white balance adjustment should be done under “nature” picture mode.
EEPROM initialization
Enter the first page of factory menu, select “clear eeprom” and then press “enter”, shut down the unit after “ok” appears.
ADC adjustment of VGA channel
Adjust ADC-gain to 15.
White balance adjustment VGA/DVI channel

Input K-7253 8 level gray-scale signal of TIME311 and PATTERN474, enter white balance adjustment menu; adjust the third and seventh levels using white balance. Select 6500k of “mode”, adjustment offset_R, offset_G and offset_B, let the color coordinate of the third level be 308 and 316 and its brightness be 16nit more or less. Adjust gain_R, gain_G and gain_B, let the color coordinate of seventh level be 308 and 316. Adjustment offset_R, offset_G, offset_B, gain_R, gain_G and gain_B repeatedly until the value of the two levels gray-scale be 308 and 316.
Select 9300k of “mode”, adjustment offset_R,offset_G and offset_B,let the color coordinate of the third level be 285 and 290 and its brightness be 16nit more or less. Adjust gain_R,gain_G and gain_B, let the color coordinate of seventh level be 285 and 290.
Select 12000k of “mode”, adjustment offset_R, offset_G and offset_B, let the color coordinate of the third level be 270 and 283 and its brightness be 16nit more or less. Adjustment offset_R, offset_G, offset_B, gain_R, gain_G and gain_B repeatedly until the value of the two levels gray-scale be 270 and 283.
Note: gain_R, gain_G, gain_B is value not above 128 and let its value 128 at least.
Adjustment TV channel
1.Adjustment VCO, OPTION, sub-brightness and sub-contrast
Input AV color bar signal (PM5518 COLOR BAR 100%) to VIDEO 1 terminal, enter the first page of factory menu, press “enter” selecting “auto color”, display “OK” after 2 seconds; then you can finish the VCO adjustment; set the value of “option” to 10, “back light” to 0 and “s-bright” to 140 as well as S-contrast to 140. set the MaxVolume according to its product standard.
2. white balance adjustment of TV channel
Input AV signal (PM5518, NTSC system, 8 level gray-scale signal), enter adjustment menu of white balance, adjust the third level and seventh level using white balance. Adjust offset_R, offset_G and offset_B to let color coordinate of the third level be 270 and 275 and its brightness be about 21nit. fixate gain_B to 128, adjust gain_R, gain_G to color coordinate of the seventh level be 280 and 280. adjust offset_R, offset_G,offset_B, gain_R and gain_G, repeatedly using the same method until
white balance adjustment YPbPr channel
input YpbPr signal of K-7253 to YPbPr-1 terminal, input TIME380(480i) PATTERN471 8 level gray-scale signal, set the value of Hor-width to 23, Ver-width to 5, S-bright to 120 and S-contrast to 140.Enter adjustment menu of white balance, adjust the third level using white balancer. Adjust offset_R, offset_G and offset_B, to let color coordinate of the third level be 270 and 275 and its brightness be about 24nit. Input 8 level gray-scale signal of TIME392(480p), TIME394(720p) and TIME396(1080i) separately, repeat the above operations to let color coordinate of the third level be 270 and 275 and its brightness be about 24nit.
Performance check
TV function
Enter searching menu
auto search, connect RF-TV terminal with central signal source and check if there are channels be skipped
AV/S, YpbPr terminals
Input AV/S, HD signal, check if it is normal.
VGA terminal
Insert VGA terminal, input VGA format signal of 640 X 480@60 Hz, check if the display is normal. If interference exists, press the auto adjust button on remote control again and check if it is normal.
DVI terminal
Insert DVI terminal, input signal of 640 X 480@60 Hz signal and check if the display is normal.
check sound channel
Check the speaker and headphone of each channel.
Method of software upgrading
Steps of software upgrading are as follows:
1. Select a serial connection wire and a VGA connection wire and then connect them by means of a patch panel;
2. Use a serial wire to connect the PC to the patch panel and set TV set to off state; Open the software upgrade file holder and double click
Based on the computer features, set up the serial port (COM Port). Select corresponding serial port (if it’s unable to FLASH WRITE, change to another port). Baud is selected to be 115200. Then select Reset Target After Download. Click FLASH pushbutton, it’s ready to run. For other settings, please refer to the Fig. Above (already defaulted by the system, normally no need to change). Switch on TV set the FLASH write program begins to run;
After FLASH write is over, push button “cancel” will become flash. Then shut the main power supply and it’s OK just switch it on again.
Note: Do not shut the power off or turn the TV set on during the FLASH write. Otherwise it may lead to no way for flash to rewrite.
BLOCK DIAGRAM 
CLICK ON THE IMAGE TO ZOOM IN


LC-37K7 working principle analysis
RF signal produces composite color television signal through TUNER201, the signal together with AV1/SVHS(SVHS priority) and AV2 etc. are sent to U29 VPC3230D to decode and do switching selection. In addition to decode the selected video signal, part of the selected video signal is also sent to AV terminal and 21 line decoder U32 Z86229 which is exclusive to decode CCD/V-CHIP to decode. After decoded by U32, the signal will be sent back to U29 in the form of R G B and FB, then it will be added to the decoded picture and then it will be sent to U13 FL12310 in the form of ITU-R656 signal format of 8BIT to do line-by-line process. Send two ways YPRPB signal to U30 MST9883 through selection by N2 PI5V330 in order to do the A/D conversion. After this, the signal will be converted into YUV signal of 24BIT, send it to FLI2310 also.
After a series of procedure such as matrix, chroma and tint etc. by FL12310, the two ways signal will be converted into RGB of 24bit, then send it to the main processing chip U12 JAG-ASM. send RGB signal it to the main processing chip U12 at the same time. There has another signal which should be sent to U12 together with he above two kinds of signal that is: RGB signal of 24BIT produced by DV1 through U15 TFP403/501. Do the picture format processing for the three kinds of signal in U12. Firstly do the A/D conversion for RGB signal of VGA, then do the switching selection together with the other two kinds of signal. And then they will be converted into 1024*768 format through digital display processing such as OSD and GAMMA correction etc. output it in the form of 24BIT RGB signal. Send it to LVDS convertor U31 DS90C383A, then it will be converted into signal format which can be accepted by LCD screen namely 3 low-voltage differential signal and 1 clock signal, finally send it to LCD screen to do the picture display PWM of U12 can also be used to control the brightness of back light-source. Send SIF (the second IF) outputted by tuner to audio processor NA01 MSP3420; send YPRPB and audio signal of DVI to NA01 through switching selection by U34 HEF4052; Send AV1/SVHS, AV2 and audio signal of VGA to NA01 also. Firstly SIF will be done the switching selection together with another four ways of audio signal, finally volume control and sound effect processing will be done. Output left-right sound channel signal R/L. one will be sent to SRS sound field processor NA03 M62494 to do SRS processing and finally amplified by NA03 and NA04 TPA3008D2 to drive the speaker, one will be used to drive the headphone through NA02 TLE2142 and the last part will be outputted as R/L of AV OUT.