REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Saturday, 9 February 2019

CHINESE COLOR TV KIT _ USING LA-76931 IC _ SERVICE HELP GUIDE

CHINESE COLOR TV KIT _ USING LA-76931 IC _ SERVICE HELP





TO ENTER FACTORY MODE
  • Press MENU button on the remote control firstly, then the press RECALL button three times sequentially to enter FACTORY MENU.
  • Press P+ or P- button on the remote control to select test item.
  • Press V+ or V- button on the remote control to adjust the value of selected item.
  • Press RECALL button again to exit FACTORY MENU.
FACTORY - 00

H-PHASE 11
OSD-H-POSITION 25
V-SIZE 82
V-POSITION 1
V-LINEARRITY 22
V-SC 4
V-KILL 0
SUB-BRIGHT 85
RF-AGC AUTO 25

FACTORY - 01

H-BLK-L 1
H-BLK-R 2
TUNER 0-3 Q Q2 A A2 0
VOL LINEAR MEASURE 1
B-Y DC LEVEL 11
R-Y DC LEVEL 10
B-Y DC LEVEL-YUV 6
R-Y DC LEVEL-YUV 6

FACTORY - 02

RED-BIAS 117
GREEN-BIAS 134
BLUE-BIAS 153
RED-DRIVE 99
GREEN-DRIVE 10
BLUE-DRIVE 92

OPTION - 00

BACK COVER OPTION 0
Q-ASM OPTION 0
OPT-AV-SYSTEM 0
Y-IN 0:P48 1:P54 1
OPT-YUV 0
LANGUAGE SW CE 1
ENG 0 : CH 1 0
ONLY ENG AND TAI 0

OPTION - 01

LV1116 OPT 0
AUDIO SW 1
SIF6.5M 1
SIF6.0M 1
SIF5.5M 1
SIF4.5M 1

POWER SUPPLY VOLTAGE ADJUSTMENT

  • Check AC voltage is normal or not, AC220V 50Hz.
  • Receive Television broadcast signal, adjust Brightness and Contrast until the standard picture is obtained.
  • Adjust RP950 until voltage between cathode of VD950 and GND of chassis is 110V±0.5V.
WHITE BALANCE AND SUB BRIGHTNESS ADJUSTMENT

BLUE BACK must be turned off and factory menu must be ON before placing the set with aging test.
  • Set Unit to AV, and set the picture to standard mode.
  • Enter FACTORY MENU 00, press P+ or P- button to choose V-KILL, then press V+ button to display horizontal light line on the screen, adjust SCREEN potentiometer so that the horizontal light line just displays anyone color of R,G and B, press V- button to restore the screen.
  • Input left black and right white signal for white balance adjustment.
  • Insert I2C controller plug which is used for automatic adjustment system into XS600 socket on the main board.
  • Turn on color analyzer CA100 to make zero correction.
  • Run the program [WB76810.exe t213.wbd]
  • Press “SPACE” key or press switch on the controller socket, white balance adjustment will be operated automatically. If OK, “ Click” will be heard.
  • Pull out I2C controller plug from XS600, receive black-white PAL five circles pattern signal, and set the picture to standard mode. Enter FACTORY MENU 00, adjust sub-brightness until black-white gray scale is 7~7.5.
HF AGC ADJUSTMENT
  • Receive signal (VHF channel)
  • Set input field strength to 60dBμV
  • Enter into FACTORY MENU 00, select RF AGC item, press V+ button to adjust RF AGC automatically, and when the adjustment is finished, the screen will display RF AGC value.
OSD POSITION ADJUSTMENT
  • Receive PAL five circles pattern signal.
  • Enter into FACTORY MENU 00 and select OSD-H-POSITION, then press V+/V- button to adjust OSD to the proper position
TECHNICAL NOTE OF LA-76931


PIN 1 SIF OUTPUT 2.8V DC
PIN 2 IF AGC FILTER
PIN 3 SIF INPUT 3.3V DC
PIN 4 FM FILTER
PIN 5 FM OUTPUT 2.5V~3.5V
PIN 6 AUDIO OUTPUT DC
PIN 7 SND APC FILTER
PIN 8 IF VCC 5V DC
PIN 9 EXT AUDIO INPUT 2.9V DC
PIN 10 ABL AUTO BEAM LIMITER
PIN 11 RGB VCC 8V DC
PIN 12
PIN 13
PIN 14
R,G,,B OUTPUT
PIN 15 NC
PIN 16 V RAMP OSC.CAPACITOR Connect 0.47uF capacitor to GND
PIN 17 VERTICAL OUTPUT
PIN 18 VCO I REFERENCE Connect 4.7k resister to GND
PIN 19 HORIZONTAL/BUS VCC 9V DC
PIN 20 AFC FILTER
PIN 21 HORIZONTAL OUTPUT
PIN 22 VIDEO CHROMA DEFLECTION GND GND
PIN 23 NC
PIN 24 NC
PIN 25 SVHS CONTROL CONTROL S OSD
PIN 26 REM Remote control
PIN 27 AV2
PIN 28 AV1
Control av1/av2 input
PIN 29 NC
PIN 30 MUTE
PIN 31 SDA I2C control
PIN 32 SCK I2C control
PIN 33 XT1 32.768KHz
PIN 34 XT2 32.768KHz
PIN 35 CPU VCC 5V DC
PIN 36 POWER Control standby
PIN 37 NC
PIN 38 AGC
PIN 39 KEY KEY control
PIN 40 RESET
PIN 41 PLL
PIN 42 CPU GND
PIN 43 CDD VCC 5V DC
PIN 44 FBP INPUT
PIN 45 C INPUT FOR Y/C MODE
PIN 46 Y INPUT FOR Y/C MODE
PIN 47 DDS FILTER
PIN 48 Y INPUT FOR YcbCr MODE
PIN 49 Cb INPUT forYcbCr MODE
PIN 50 4.43MHz CRYSTAL
PIN 51 Cr INPUT FOR YcbCr MODE
PIN 52 SELECTED VIDEO OUTPUT OR FSC OUTPUT
PIN 53 CHROMA APC FILTER
PIN 54 EXT VIDEO INPUT
PIN 55 VIDEO CHROMA DEFLECTION VCC
PIN 56 INT VIDEO INPIT
PIN 57 BLACK STRETCH FILTER
PIN 58 PIF APC FILTER
PIN 59 AFT OUTPUT
PIN 60 VIDEO OUTPUT
PIN 61 RF AGC OUTPUT
PIN 62 IF GROUND
PIN 63 PIF AMP INPUT
PIN 64 PIF AMP INPUT

LA - 76931 BLOCK DIAGRAM


Posted By: FRANK at 01:34
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