Before removing the rear cover from the TV for servicing, make
sure that no cables are fixated to the cover. Release the cables from their
clamps and disconnect (if any). Failure to do so may damage the wires and other components of the TV.
17MB171 main board is driven by MTK SOC. This IC is a single chip iDTV solution that supports channel decoding, MPEG decoding, and media-centre functionality enabled by a high performance AV CODEC and CPU.
T-T2-C-A TUNER (U118)
The Si2151 is Silicon Labs' sixth-generation hybrid TV tuner supporting all worldwide terrestrial and cable TV standards. Requiring no external balun, SAW filters, wire wound inductors or LNAs, the Si2151 offers the lowest-cost BOM for a hybrid TV tuner. Also included are an integrated power-on reset circuit and an option for single power supply operation. As with prior-generation Silicon Labs TV tuners, the Si2151 maintains very high linearity and low noise to deliver superior picture quality and a higher number of received stations when compared to other silicon tuners. The Si2151 offers increased immunity to WiFi and LTE interference, eliminating the need for external filtering. For the best performance with next-generation digital TV standards, such as DVB-T2/C2, the Si2151 delivers industry-leading phase noise performance.
MAIN AMPLIFIER (U123) (8W-10W-12W OPTIONS)
AD82587D is a digital audio amplifier capable of driving a pair of 8 ohm, 20W or a single 4 ohm, 40W speaker, both which operate with play music at a 24V supply without external heat-sink or fan requirement. Using I2C digital control interface, the user can control AD82587D’s input format selection, DRC (dynamic range control), mute and volume control functions. AD82587D has many built-in protection circuits to safeguard AD82587D from connection errors.
Power Socket and Power Options
Power socket is used for taking 12V_STBY voltage which is produced in power card. Also socket is used for giving dimming, backlight and standby signals with power card. Power socket pinning is shown in figure.
12V_STBY is converted to several different voltages on the mainboard which are shown in below figure.
SAMSUNG EMMC 8GB KLM8G1GETF-B041 BGA153 (U128)
SAMSUNG eMMC is an embedded MMC solution designed in a BGA package form. eMMC operation is identical to a MMC device and therefore is a simple read and write to memory using MMC protocol v5.1 which is a industry standard. eMMC consists of NAND flash and a MMC controller. 3V supply voltage is required for the NAND area (VDDF or VCC) whereas 1.8V or 3V dual supply voltage (VDD or VCCQ) is supported for the MMC controller. SAMSUNG eMMC supports HS400 in order to improve sequential bandwidth, especially sequential read performance. There are several advantages of using eMMC. It is easy to use as the MMC interface allows easy integration with any microprocessor with MMC host. Any revision or amendment of NAND is invisible to the host as the embedded MMC controller insulates NAND technology from the host. This leads to faster product development as well as faster times to market. The embedded flash management software or FTL(Flash Transition Layer) of eMMC manages Wear Levelling, Bad Block Management and ECC. The FTL supports all features of the Samsung NAND flash and achieves optimal performance.
MAIN SOFTWARE UPDATE
Method-1
1. Copy MstarUpgrade.bin to USB stick (root directory, FAT32)
2. Enter M-Boot console first (Long press "ENTER" key on Tera Term Console when your device reboot then do AC On)
3. Plug the USB stick to your target board
4. Execute "custar" in M-Boot console to perform upgrading
Method-2
1. Copy upgrade_loader.pkg to root folder of USB stick (or copy upgrade_loader_no_tvcertificate.pkg if you don't want to erase keys, credentials, etc.)
2. Insert USB disk to one of the USB ports on your TV
3. Power on TV and wait until you see the bootlogo
4. You should see logs like below.
NO BACKLIGHT PROBLEM
Backlight pin, dimming pin, backlight supply, stby on/off pin
BACKLIGHT_ON/OFF pin should be high when the backlight is ON. Collector pin of Q113 must be low when the backlight is OFF. If it is a problem, please check Q181. Also it can be tested in TP500 or Pin5 of CN2 in main board. Please also check panel cables.
Dimming pin should be high or square wave in open position. If it is low, please check S294 for MTK side. It also can be checked at TP499. Please also check panel or power cables and connectors.
CI is not working when CI module inserted.
CI supply should be 5V when CI module inserted. If it is not 5V please check CI_PWR_CTRL, this pin should be low.
Check mechanical position of CI module. Is it inserted properly or not?
Detect ports should be low. If it is not low please check CI connector pins, CI module pins.
NO SOUND PROBLEM
Check supply voltages of 24V_VCC, VDD_AUDIO and 3V3_AMP with a voltage-meter. There may be a problem in headphone connector or headphone detect circuit (when headphone is connected, speakers are automatically muted). Measure voltage at HP_DETECT pin, it should be 3.3V.
STANDBY ON-OFF PROBLEM
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 program. These printouts may give a clue about the problem. You can use VGA for Teraterm program connection.
SERVICE MENU
In order to reach service menu, first chose Channel, then press “MENU” buton, press “Advanced Options” then write “4725” by using remote controller.
You can see the service menu main screen below. You can check SW releases by using this menu under Diagnostic title. In addition, you can make changes on video settings, audio settings, DAP Parameters etc. using regarding titles. You may also use USB Operations for SW update and update Unique Keys and Configuration files.