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
measure the 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
