No sound, LED blinking, standby ON/OFF, No signal. Service menu settings – Vestel 17IPS62, Vestel MB82S
AUDIO AMPLIFIER-TAS5721 (optional)
The TAS5721 is a 15-W stereo or 2x10 W + 1x15 W2.1 device, efficient, digital audio-power amplifier for driving stereo bridge-tied speakers. One serial data input allows processing of up to two discrete audio channels and seamless integration to most digital audio processors and MPEG decoders. The device accepts a wide range of input data and data rates. A fully programmable data path routes these channels to the internal speaker drivers. The TAS5721 is a slave-only device receiving all clocks from external sources. The TAS5721 operates with a PWM carrier between a 384-kHz switching rate and a 352-KHz switching rate, depending on the input sample rate. Oversampling combined with a fourth- order noise shaper provides a flat noise floor and excellent dynamic range from 20 Hz to 20 kHz.
Audio Input-Output
– 15Wx2 into 8Ω
– Supports Single Device 0.1, 2.0, 2.1 Modes
– Wide PVDD Range, From 4.5 V to 26 V Performance
– Efficient Class-D Operation Eliminates Need for Heatsinks
– Requires Only 3.3 V and PVDD
– One Serial Audio Input (Two Audio Channels)
– I2C Address Selection via PIN (Chip Select)
– Supports 8-kHz to 48-kHz Sample Rate (LJ/RJ/I2S)
– External Headphone-Amplifier Shutdown Signal
– Integrated CAP‐Free Headphone Amplifier
– Stereo Headphone (Stereo 2‐V RMS Line Driver) Outputs
• Audio/PWM Processing
– Independent Channel Volume Controls With The 24-dB to Mute
– Separate Dynamic Range Control for Satellite and Sub Channels
– 21 Programmable Biquads for Speaker EQ
– Programmable Coefficients for DRC Filters
– DC Blocking Filters
– Support for 3D Effects
• General Features
– Serial Control Interface Operational Without MCLK
– Factory-Trimmed Internal Oscillator for Automatic Rate Detection
– Surface Mount, 48-Pin, 7-mm × 7-mm HTQFP Package
– Thermal and Short-Circuit Protection
POWER STAGE
The DC voltages required at various parts of the chassis and panel are provided by a main power supply unit. MB82S chassis can operate with PW05, IPS60, IPS70, IPS16, IPS17, IPS19, PW25, PW26, PW82-3, PW03, PW04, PW06, PW07 as main power supply and also with 12V adaptor.
Which power board can be used for board to board or cable connection?
Board to board (BTB) : PW05, IPS60, IPS70, IPS16, IPS17, IPS19
Power Cable : PW25, PW26, PW82-3, PW03, PW04, PW06, PW07
The power supplies generate 24V, 12V, 5V, 3,3V and 12V, 5V, 3.3V stand by mode DC voltages. Power stage which is on-chassis generates 5V, 3V3 stand by voltage and 12V, 8V, 5V, 3V3, 2.5V, 1,8V and 1,2V supplies for other different parts of the chassis.
For PW26 and PW27 just common blocks are enough for proper operation.
Short CCT Protection Circuit
Short circuit protection is necessary for protecting chassis and main IC against damages when any Vcc supply shorts to ground. Protect pin should be logic high while normal operation. When there is a short circuit protect pin should be logic low. After any short detection, SW forces LEDs on LED card to blink.
Panel Supply Switch Circuit
This switch is used to open and close panel supply of TCON. It is controlled by port of main u-controller. Also with this circuit panel sequence could be adjusted correctly. 3 panel supplies are connected to this circuit. All of them are optional according to panels.
SERVICE MENU SETTINGS
In order to reach service menu, First Press “MENU” Then press the remote control code two times, which is “4725”.
In first screen following items can be seen (MB8x is same as MB6x service menu):
USB Operations
USB operations option can not be used directly. It can be used for updating panel tool, hw configuration etc.
SOFTWARE UPDATE
In MB82 project there is only one software. From following steps software update procedure
can be seen:
1. MB82.bin directly inside of a flash memory (not in a folder).
2. Put flash memory to the tv when tv is powered off.
3. Power on the and OK button on the remote control when the tv is opened.
4. If First Time Installation screen comes, it means software update procedure is successful.
TROUBLESHOOTING: No Backlight Problem
Problem: If TV is working, led is normal and there is no picture and backlight on the panel.
Possible causes: Backlight pin, dimming pin, backlight supply, stby on/off pin Backlight pin should be high in open position. If it is low, please check Q30 and panel cables.
Dimming pin should be high or square wave in open position. If it is low, please check S16 for Mstar side and panel or power cables, connectors.
Backlight power supply should be in panel specs. Please check CN4 for MB82, related connectors for power supply cards.
CI Module Problem
Problem: CI is not working when CI module inserted.
Possible causes: Supply, supply control pin, detect pins, mechanical positions of pins CI supply should be 5V when CI module inserted. If it is not 5V please check CI-POWER-CTRL, this pin should be low.
Please check mechanical positions of CI module.
Detect ports should be low. If it is not low please check CI connector pins, CI module pins and 3V3-VCC on MB82.
Led Blinking Problem
Problem: LED blinking, no other operation
This problem indicates a short on Vcc voltages. Protect pin should be logic high while normal operation. When there is a short circuit protect pin will be logic low. If you detect logic low on protect pin, unplug the TV set and control voltage points with a multimeter to find the shorted voltage to ground.
No Sound Problem
Problem: No audio at main TV speaker outputs.
Check supply voltages of VDD-AUDIO, 5V-VCC or 12V-VCC 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.
No Sound Problem at Headphone
Problem: No audio at headphone output.
Check HP detect pin, when headphone is. Check 5V-VCC and 3V3-VCC with a voltage meter.
Standby On/Off Problem
Device cannot boot, TV hangs in standby mode.
There may be a problem about power supply. Check 12V-VCC, 5V-VCC and 3V3_VCC 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 hyper-terminal (or Tera term). These printouts may give a clue about the problem.
No Signal Problem
Problem: No signal in TV mode.
Check tuner supply voltage; 3V3-TUN. Check tuner options are correctly set in Service menu. Check AGC voltage at IF-AGC pin of tuner.
Schematic diagram
