Question about Thomson 30LCDB03B 30 in. HDTV

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Thomson TV I have replaced a defective Vrt. Amp TDA8178F I.C. All in put Voltages are O.K. But there is only a Hor. Line. At pin no.1 I get about 500mV pp, saw tooth wave. Can some one be kind to advice me. ThanksNb:Model Thomson TVĀ  55DF71 EX Suraweera

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Lg 50LN400-ua is the led driver on the power board

The power supply has the LED driver circuitry built in. I would suggest to measure the voltages without the LEDs connected to the power supply, if the voltages are present without the LEDs connected then you have a defective LEDs strips inside the panel. If the voltage is low or absent, the power supply should be replaced.

Oct 18, 2015 | LG Flat Panel Televisions

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Vizio logo does not light up amber when plugged in but turns white when power button is pressed. no picture or sound. Big Transformer on power board makes a light buz sound when plugged in also.

1. When the TV powered up, please measure the 24V, 12V & 5V are there, if one voltage is missing, you may have a defective power supply.

2. If the power supply lost the 24V source, you may unplug the power supply connector on both the inverter board, then power it up, if you got the 24V back, you do have a defective inverter board, you may unplug them one at a time to locate the bad one.

3. If the power supply & inverters are good, you may have a defective main board. The common problem on the main board is that a voltage regulator is bad, you may use your millimeter to measure them 1 x 1. The out put voltage (on the heat sync) should be 1.25V + the control voltage (Pin 1), for example: if the control pin voltage is 0, the output voltage should be 1.25V, if the control voltage is 2.05V, the output voltage should be 3.3V, if one of them is out of range, replace it, you may find the part from Digikey Co. The part number printed on the regulator is AMC1117.

Good luck!

Apr 08, 2015 | Vizio VX42L 42 in. LCD TV

1 Answer

What can I check to determine if my TV's Power Supply is bad?

Iv the voltages are low, pull the power line from each of the other boards to see which one is dragging the voltages down. If none ovf the voltages return to the correct value, then the power supply board is gone. You can get all the repair parts you need from here:

Feb 19, 2015 | Flat Panel Televisions

1 Answer

Samsung Plasma won't power on

this is not a capacitor problem. set is only 18 months old - has something to do with x y sustain boards not allowing smps to power on the high voltages.

May 27, 2013 | Samsung Flat Panel Televisions

1 Answer

Power supply problem no switching

( "Power Supply Problem Not Switching "???? )

How do you know it's Not Switching? Do you mean the TV wont turn on when you push the power button on and off on the TV and also with the remote control unit? Is that what you mean? If YES! Then, If your Vizio TV wont turn on and has NO-PICTURE, NO-SOUND and a BLACK SCREEN, Then the TV has an AC or a DC Voltage Problem.

1 - First, check the wall outlet socket by pluging in a lamp to see if you have 110 AC-volts there. If the lamp works, the wall outlet is OK! That means the problem is inside the TV.

2 - Before, you remove the back off the TV. I want to *(CAUTION - YOU)* The Power Voltages inside your TV are Very, DANGEROUS!!! There is 110 AC Volts at a 20-AMP-Rating ***CAN BE A LETHEL DEADLY SHOCK HAZARD to HUMANS!!!*** Also there are DC Voltages ranging from 3.3 to 24 volts. And R-F- VERY-HIGH-VOLTAGE of 20,000 Volts or More.

3 - You will need hand tools and a Digitle Volt Ohm Meter to check AC & DC Voltages and the OHMS Meter section to check resistors, capacitors, coils, grounds and contacts.

4 - With the Back removed, and no-power to the set. Inspect the power board for any signs of BURNED, LOOSE or BROCKEN parts like resistors, capacitors, coils, fuses on all boards. If you discover damaged parts, make a list of them. Then you must deside if you are qualified to do the on board repair or just order a new replacment board.

5 - If on the other hand you didn't discover any damaged parts by your inspection, It's time to put the Meter to good use. Plug the TV power cord to the wall outlet. Set the Meter for AC - voltage range of 200 or more. check for 110 AC volts going to the power supply board fused inputs.
If NO replace the cord. If YES, look on the board for voltage test points marked on the board. (SAMPLE!) 3.3 vdc, 5 vdc, 12 vdc, 24 vdc, and so on. Set Meter for DC Volts now, range 50 to 100. Put the black lead to ground and the RED lead to each test point marked on the board while repetetedly pressing the TV power on & off button..

6 - If ANY of the DC voltages were LOW, WRONG or MISSING, The Main power board is defective and needs to be removed and replaced with a new one. Write down the board number that is on the board and use that number to order the new one. You can order it on the Net!

*****(NOTE)***** If you are not an electronics tech. don't try to fix the old defective board... but, keep it handy, you might need it for parts later. :-)

Hope This helped... GOOD LUCK! NOW, GO FIX YOUR TV!

Oct 08, 2012 | Vizio L32 32 in. LCD HDTV

1 Answer

Red light blinking

blinking of red light indicates that fault in main board or related boards. you need to open back cover remove each cable connected with main board one by one & put on tv after each cable is disconnected. if red light stops blinking on disconnecting any of the cables, that means related board is defective, if it does not stops blinking, check the power supply is generating proper voltages. if it is ok that means the main board is defective.

Sep 26, 2011 | Panasonic TC-32LX24 32 in. LCD TV

2 Answers

Sir, hamari tv ka name thomson hai hamari tv

there is problem with your power supply.Must be fuse,capacitor,Str or FET are short or open.But care fully there is live voltages if you know that how to replaced then ok.

Oct 18, 2010 | Thomson LCDB 03B 27 in. Television

1 Answer

42 in magnavox plasma tv has sound with no picture I unplugged tv and waited 10 minutes with no luck

Hi my name is Roety,
I can help you with your issue ,
If you have no TV menu either check for any swollen capacitors on the power supply.
If none are found measuring voltages will localize the defective board or boards the voltage test points are marked VA and VS on the panel and boards.
If disconnecting boards restores these voltages the suspected boards must be replaced .
Tech labor is about $250 plus parts.
Suspected boards
power supply
Y sus main & Y buffers  
Logic board
If I have helped you with your issue
If you have more questions you can still respond
I will reply asap

Dec 30, 2009 | HP PL4245N 42 in. HD-Ready Plasma...

1 Answer

LG 50" plasma

Do you get sound on Audio Line-Out pins of LG TV?
You can check sound at Audio Line Out pins by connecting any Amplifier / Home Theater system. If TV has sound out at Line Out terminals, then Output Amp is defective in your TV.
If there is no sound on above said pins, then its some thing complicated and needs service manual to rectify.
Good Luck.

Nov 06, 2008 | LG 50PC5DC 50 in. Plasma HDTV

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