CONTENTS 1 MAIN BOARD TROUBLE SHOOTING GUIDE 1.1 SHORT TEST 1.2 POWER 1.3 MAIN CLOCK 1.4 CVBS 1.5 RGB 1.6 AUDIO # ADDITIONAL TROUBLESOOTHING 2 SCHEMATIC.COMPONENT LAYOUT AND BOM OF POWER SUPPLY 2.1 SCHEMATIC OF POWER SUPPLY 2.2 COMPONENT LAYOUT OF POWER SUPPLY 3 SCHEMATIC.COMPONENT LAYOUT AND BOM OF MAIN BOARD 3.1 SCHEMATIC OF MAIN BOARD 3.2 COMPONENT LAYOUT OF MAIN BOARD...
Main Board Main Board Trouble Shooting Guide (DTT1609) Here are the procedures you can refer to whenever terrestrial receivers do not operate properly. You can check problems and repair the units on the basic level according to the following procedures...
1. SHORT TEST ☞Before turning on AC power, check POSITIVE VOLTAGE and also check whether SHORT between GROUND's and PIN SHORT for TUNER are detected or not. 2. Checking POWER. +12V(SCART),+5V(ANTENNA_POWER,IR,VIDEO BUFFER,HDMI,USB), +3.3V(TUNER, FLASH, ☞ CPU),+2.5V(DEMOD),+1.5V(DDR3,CPU),+1.3V(CPU DEMOD)
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+3V3 +3V3 For Cpu +1V3 For +1V5 For Cpu +1V5 For DDR3...
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+2V5 For DEMOD +1V3 For DEMOD +5V For +5V For Video Buffer +5V For Audio...
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3. Check MAIN CLOCK 24MHz and SYSTEM CLOCK (PLL) to operate normally after SYSTEM operates. For the first thing, check 24MHz from Y401 flows into [OSCI(PIN B18)] of MAIN ☞ If the 24MHz is unstable, Check Y401 is damaged or not. If you are firm belief of damage for the device, then replace the device.
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4. In case that MAIN CPU operates normally but there is no VIDEO display. In case of no OSD display. ▶ If OSD is not displayed, check first if VIDEO SIGNAL is detected from ☞ [R419(CVBS),R416(R),R417(G),R418(B)] of MAIN CPU. And then, check any part with no DATA after checking VIDEO SIGNAL from VIDEO ☞...
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VIDEO SIGNAL If wave-form is not like this picture, check that wave-form output is normal from each terminal...
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5. In case of no MPEG and no OSD at the same time. Check that 1Vp_p(0.7Vp_p for RGB) comes out normally from VIDEO PART(CVBS) of ☞ MAIN CPU. CVBS GREEN BLUE 7. In case of normal VIDEO SIGNAL flowing out but abnormal AUDIO SIGNAL. Check that ADAC_L(U201 PIN2),ADAC_R(U201 PIN9) signals have normal inputting and ☞...
# ADDITIONAL TROUBLESOOTHING 1) STAND-BY mode on Set. Ordinarily, STAND-BY mode results from SHORT on LNB. Check first if TR on LNB has stopped, and then in case that STAND-BY mode resulted from wrong software, down-load a proper software. POWER SWITCH There is a TR's as a switching role on the LNB bundle.
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2) Screen problem in color If you have Black-and-White screen. It mainly results from distorted 24MHz frequency. In case of no screen display or different color displayed, it also mainly results from the Y401 problem. Additionally, in case that the screen display works but is with one color only, for example blue, green, or red, it mainly results from software fault(possiblely detected only on RGB TV).
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signal input Blue signal input Green signal input...
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3) Weak TUNER signal Check first that the voltage is impressed to LNB. If there is nothing wrong in LNB Voltage, check if the voltage is impressed well into TUNER bundle and if data flow out properly. If every condition is satisfied, TUNER itself can be considered to be defective.
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4) Screen ratio problem If a strange ratio in 4:3 and 16:9 is detected, the voltage of TV scart pin number 8 is below 9V. In case of around 7V, screen will be shown with 16:9 ratio. In case of over 10V, the ratio will be 4:3.
2.2 COMPONENT LAYOUT OF POWER SUPPLY 3 SCHEMATIC.COMPONENT LAYOUT AND BOM OF MAIN BOARD 3.1 SCHEMATIC OF MAIN BOARD...
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HISTORY OF MODIFICATIONS REV. CHECK.BY APP.BY DATE Version History BLOCK DIAGRAM V1.0: 2011-07-24 Created LOW IF T2 DEMOD TUNER I2C,AGC (MSB1230) CVBS Y/PB/PR Video buffer DDR3 (128MB) SCART Audio OP Serial FLASH (4MB) MSD5043-V60 SPDIF Nand FLASH HDMI1.3 (128MB) EEPROM (2KB) RJ45 POWER...
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FOR D191 LED SUPPORT 12MM J501 USB-A-04,USB插座,侧弯90度 SW101 SWITCH PUSH 6X6X2DH5 H:1.5mm TUNER2 DVB-T2/T TUNER:FH-RT232A4 9+2PINS 立式 (FOR U401) Heat SINK(25*25*20 white )
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# OTHER TROUBLESOOTHING 1, Testing the chip and the DEMOD's crystal frequency(Y401 Y701) with a frequency spectrograph, to make sure it's within ±20PPM(±480HZ); 2, If there is a heavy mosaic when your STB works, or even NO SIGNAL, please change the crystal in the TUNER;...
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3, If the fuse blew out, please change the F902 and check the D910,D911,D912,D913,to see if they are burnout.
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