Sharp LC-50LE771E Service Manual ▷ View online
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H. Standby On/Off Problem
Problem: Device can not boot, TV hangs in standby mode.
There may be a problem about power supply. Check main supplies with a voltage-meter. Also
there may be a problem about SW. Try to update TV with latest SW. Additionally it is good
to check SW printouts via Teraterm. These printouts may give a clue about the problem. You
can use Scart-1 for terraterm connection.
I. No Signal Problem
Problem: No signal in TV mode.
Check tuner supply voltage; 5V_VCC, 3V3_TUNER and 1V8_TUNER. Check tuner options
are correctly set in Service menu. Check AGC voltage at IF_AGC pin of tuner.
9. No Signal Problem
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CHAPTER 7.MAJOR IC INFORMATIONS
[1] INTRODUCTION
3
1. INTRODUCTION
17MB90-2 main board is driven by MStar SOC. This IC is a single chip iDTV solution
that supports channel decoding, MPEG decoding, and media-center functionality enabled by a
high performance AV CODEC and CPU.
Key features includes,
Combo Front-End Demodulator
A multi standart A/V format decoder
The MACEpro video processor
Home theatre sound processor
Internet and Variety of Connectivity Support
Dual-stream decoder for 3D contents
Mılti-purpose CPU for OS and multimedia
Peripheral and power management
Supported peripherals are:
1 RF input VHF I, VHF III, UHF
1 Satellite input
1 Side AV (CVBS, R/L_Audio)
2 SCART socket(Common)
1 YPbPr (Common)
1 Side S-Video(Common)
1 PC input(Common)
4 HDMI input(Common)
1 Common interface(Common)
1 Optic S/PDIF output(Common)
1 Stereo audio input for PC(Common)
1 Subwoofer output(Common)
1 Headphone(Common)
2 USB(Common) and 2 Optional for Air mause and Wi-Fi dongle
1 Ethernet-RJ45 (Common)
1 External Touchpad(Common)
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2. TUNER
A. SI2156 Terrestrial and Cable TV Tuner:
A.1. Description:
The Si2156 integrates a complete hybrid TV tuner supporting all worldwide terrestrial and
cable TV standards. Leveraging Silicon Labs’ field proven digital low-IF architecture, the
Si2156 maintains the unmatched performance and design simplicity of the Si2153 while
further reducing footprint size and bill of materials cost. No external LNAs, tracking filters,
wirewound inductors, or SAW filters are used.
Compared with competing silicon tuners and discrete MOPLL-based tuners, the Si2156
delivers superior picture quality and a higher number of received stations in crowded and
near/far real-world reception conditions. The high linearity and low noise RF front-end
delivers superior blocking performance and higher sensitivity in the presence of strong
undesired channels and interference.
The Si2156 integrates the complete signal path from antenna input to IF outputs for both
analog and digital transmission standards. Compared to traditional discrete MOPLL-based
tuners, the Si2156 eliminates hundreds of external components including external LNAs,
tracking filter varactors and inductors (unlike competing silicon tuners), and SAW filters,
resulting in the simplest, lowest-cost BOM for a hybrid TV tuner.
Interfacing the Si2156 seamlessly with the Si2165 DVB-T/C demodulator creates a
complete terrestrial and cable DVB-T/C receiver plus PAL/SECAM tuner.
A.2. Features:
- Worldwide hybrid TV tuner
- Analog TV: NTSC, PAL/SECAM
- Digital TV: ATSC/QAM, DVB-T/T2/C, ISDB-T/C, DTMB
- 42-1002 MHz frequency range
- Compliance to A/74, NorDig, D-Book, C-Book, ARIB, EN55020, OpenCable™
specifications
- Best-in-class real-world reception
- Exceeds discrete MOPLL-based tuners
- Highly integrated, lowest BOM
- No SAW filters or wirewound inductors required
- Integrated LNAs and complete tracking filters
- No alignment, tuning or calibration required
- Digital low-IF architecture
- Integrated channel select filters
- Flexible output interface
- ALIF to analog TV demodulator or SoC
- DLIF to digital TV demodulator or SoC
- 3.3 and 1.8 V power supplies
- Standard CMOS process technology
- 5 x 5 mm, 32-pin QFN package
- RoHS compliant
1 .TUNER
[2] MAJOR IC INFORMATIONS
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