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Lcd power supply

I need a Potrans 19v power supply for my lcd tv. Where can I order one?

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This is a no-name set. You should go back to where you bought the set and find out who is doing their warranty service. They may not sell the parts directly, if parts are even available.

The power supply may be in protect mode or damaged because there is a fault somewhere else in the set. This should be verified.

Jerry G.

Posted on Jun 10, 2008

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The picture fades out and then I can!t turn it off, after 30 minutes or
longer it will go off. If I unplug the potrans and plug it back in it
usually comes back on for a few days and then we start over.

Posted on Mar 27, 2009

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My LG 42LH30 UA LCD TV WONT POWER ON WAHTA CAN I DO TO FIX IT


open it up check the power supply for busted/swollen or leaking caps if it has some change them out with new caps with same uf and voltages (although you cna up the voltage a little) - check the voltages coming from the power supply if the tv will stay on long enough to do so - if not order a power supply

thanks,
michael

Mar 21, 2011 | LG 42LH30 42 in. LCD TV

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Hi, great writeup! I'm using it to troubleshoot a philips 37MF331D lcd tv. I...


This is the basic guide that can be applied to most LCD flat panel TV.
By Bud Martin
First, try unplugging it from the outlet for about an hour to see if the TV will reset itself since the minute the TV is plugged into the wall, the power supply and processor will be running 24/7 and the EPROM can get corrupted by spikes and surges. Try using good quality surge suppressor to see if it will help if it happen often.
Look for burnt brown hot spots on the circuit boards, capacitors with leaking/bulging top or seals. Loose wires and connectors. Blown fuses.
Notes: We are dealing with high voltage that can kill you! so if you are not sure what you are doing, please have it fixed by the pro that has proper tools and safety equipment. Try to use GFI outlet and isolation transformer when work around the TV set and DO NOT DEFEAT THE GROUND PIN OF THE OUTLET/POWER CORD.

1) The power supply module (There are 4 regulated output voltages:- Standby 5vdc, switched 5vdc, 12~16vdc, and 24vdc).

The power supply converts the 120/230vac 50/60Hz into DC, then the high frequency (50~100kHz) switching circuits convert it back to AC but at high frequency which allows the power supply to use smaller and much lighter weight transformers (Ferrite core instead of heavy iron core), then this high frequency AC voltage is fed to the rectifier Diodes to get the DC output and filtered by DC filter capacitors that must have low ESR (Equivalent Series Resistance), if general purpose electrolytic caps are use, they will fail within a year or less due to high ESR.

The power supply has Standby 5vdc (5VSB, this is a MUST have before anything else will work, when this voltage is not present, there will be no any indicator light on the front panel) which is always on the minute the TV is plugged into the AC outlet, so it is on 24/7 and that is why the power supply will fail even though you may use the a TV not very often. It will see all the voltage spikes and surges 24/7.
This 5vdc is used to power the Processor and the Infrared remote receiver module which will be waiting for the command from the remote control or from the power switch, when the Power on command is received, the Processor will send the turn on signal (3.3~5vdc) to the power supply module (PSON pin) to the switch on the main 5vdc for the rest of the logic and Tuner circuits, 12~16vdc for the sound amplifiers (mostly Class D amplifier for efficiency and small size) and for the T-CON board (interface board between the LCD panel, some T-CON uses 5vdc, and the Logic board), and 24vdc for the Back lights inverter board (if there is no 24vdc then no back light).
Common failures:
Blown main AC fuse due to shorted out Diodes, transistors.
Bad capacitors leaking or bulging tops:
Shorted Diodes, transistors in the DC output side.

Testing the power supply output with dummy load:
24vdc testing: Disconnect the wires that go to the inverter board first. You can use two #1157 (using both Lo & Hi filaments by paralleling them at the base) car light bulbs connected in series so they can handle the 24vdc, this will put light load (about 70w) on the 24vdc output, the voltage out should be steady at 24vdc (+/-2v), if not, the power supply has regulation problem.
12vdc testing: disconnect the 12vdc TV load from the power supply board and attach one #1157 (using just the Hi filament), the 12vdc output should stay at 12v (+/-1v), if not, the power supply has regulation problem.

You should see the lamps go on when the TV power switch is ON and go OFF when the TV is powered OFF.

2) Main Logic board (It has Processor, Tuner, Sound Processor, Sources selector, Power amplifiers for speakers, interface port to the T-CON board for pictures).
This logic board sends out the turn on signals (3.3~5vdc) to turn on the rest of the Power supply module (Switched main 5vdc, 12~16vdc, and 24vdc), Inverter backlight ON (if no back light on command then there is no back lights),
Logic board supplies 5 or 12vdc to T-CON board B+ pin through switched transistor if T-CON board does not get the voltage from the logic board, you will get white/gray glowing screen without pictures.
Back lights Dimming (PWM) control signal.

3) Back lights Inverter board. Its job is to provide the drive voltage for the CCFL (Cold Cathode Fluorescent Lamp) to give white light for the screen.
This board is fed by the switched 24vdc (VBL) from the power supply module, it also get the Back lights on (BL on) control signal and the Dimming (Dim/PWM/) signal from the logic board. So for it to work, it needs 24vdc and the BL_ON signal.
Common failures:
Blown surface mounted fuses due to shorted transistors/ICs, Transformers.
Bad capacitors.

4) The T-CON (Timing Control or LCD controller) board (on the LCD panel assembly). It transfer the universal image signal of TTL and LVDS signal to specific TFT (Thin Film Transistor) LCD.
This is the interface board that talks to the Logic board and the LCD panel to produce pictures on the screen. White/gray glowing screen when it fails or not getting the voltage from the logic board (the 5 or 12vdc is supplied by switched transistor on the logic board). Notes: T-CON board is mounted under the metal cover shield.
Common failures:
Scrambled pictures, Lines, multiple pictures, color smears/blotches, rolling pictures after warm up.
Blown surface mounted fuse.
No pictures, very dark screen almost like there is no backlights.

5) LCD panel assembly to display pictures. The LCD pixels will block or unblock the back lights from the back of the panel to the front of the panel. This is the most expensive part of the TV, it will be more than the TV is worth.

As you can see, you must have all the above Voltages and signals for the TV to work properly. This may help you narrowing down the bad modules instead of buying the wrong module just to find out later that it did not solve the problem. Hope this will help you out.

Sound problem:
Let verify first to narrow down to where the problem can be. First, check the on screen sound set up menu to make sure the speakers are not set to OFF. If the setting is OK, then attach the powered PC speakers to the Audio Line out RCA jacks to see if you can get the sound there, if you do, then the problem can be in the power amp circuits, if you do not get the sound at RCA jacks, then the problem can be in the sound processor circuit. To get the sound repair, it can be from $150 and up, so if you can put up with using the good set of Powered PC speakers which actually give better sound than the tiny speakers inside the TV, I would keep using it that way, you may want to find out if the on screen sound setup will allow you to set the audio line out to be VARIABLE which means the sound output feeding the PC speakers can be varied using the TV remote control, then all you have to do is to set the PC volume to about half way up and set the TV volume to what ever you want.

Inverter board connector: you can also see the Fuse 4A/160V
http://i.fixya.nethttp://i.fixya.net13ca788.jpg
Power supply connector:
http://i.fixya.nethttp://i.fixya.net78e0d9a.jpg

http://i.fixya.nethttp://i.fixya.net2fc510f.jpg
T-CON board: (metal cover shielding is removed to show the bd.)
http://i.fixya.nethttp://i.fixya.net0b5367e.jpg
Inverter board:
http://i.fixya.nethttp://i.fixya.netaf0a695.jpg
Logic board:
http://i.fixya.nethttp://i.fixya.net4bd108e.jpg
T-CON board is dead, no power or blown fuse on the board, screen turns WHITE, must see it in darkened room, otherwise you may mistaken it for failed backlight.
http://i.fixya.nethttp://i.fixya.net3a91b68.jpg
Bad T-CON board after warm up, you get lines, multiple pictures, strange colors blotches, etc.
http://i.fixya.nethttp://i.fixya.netd3cf194.jpg
Bad caps (leaking/bulging tops). Make sure to replace bad cap with good cap such as PANASONIC FM or FC series , they are Low ESR (Equivalent Series Resistance) which is a must for switch mode power supply, and 105c rating. Do not use generic electrolytic caps.
http://en.wikipedia.org/wiki/Capacitor_plague

http://i.fixya.nethttp://i.fixya.netbe827ec.jpg
Bad T-CON board or power supply problem

http://i.fixya.nethttp://i.fixya.net034e1db.jpg

24vdc power supply output testing using two 12vdc car lamps in series.

http://i.fixya.nethttp://i.fixya.net4f2929c.jpg
Bad LCD panel, vertical 1~2 pixel wide lines
http://i.fixya.nethttp://i.fixya.net28e50c1.jpg
Failed TV and Monitors: http://s807.photobucket.com/albums/yy352/budm

Free service manuals: www.elektrotanya.com

on Nov 07, 2010 | Sony BRAVIA KDL-40S2010 40 in. LCD...

2 Answers

I bought this Thomson TV in the Netherlands and moved to the USA and now need a power cord for model nr 20LCDBO3B with serial number FRN104824 (19V DC) Thanks


I thought the power adapters were multi voltage. Have a close look as if it is a switch mode type, you may be lucky and just have to change the plug top over.
If not try ebay

Feb 12, 2011 | Thomson 20LCDB03B 20 in. Television

1 Answer

Need power supply for astar ltv-32asb tv


Click here to find the power supply for you LCD. I would suggest to check the power supply part number from your LCD before ordering.

Nov 03, 2010 | Astar LTV-3201 32 in. LCD Television

1 Answer

Power supply is shot ..need a new one and the repair place said they can't order one. Olevia Model LT30HV


Does it have a lot of bad capacitors (bulging top)? Do you have the picture of the power supply? Two most common parts that go bad in the LCD TV are the power supply and the Backlight Inverter board.

Oct 28, 2009 | Olevia LT32HVM 32 in. LCD Television

1 Answer

Tv shuts off after only a minute of play


Hi!

Sounds like you have a bad power supply board! This is not hard to do yourself, as long as you are somewhat handy! Take the case apart (back side), and look for some bad caps (capacitors) on the power supply board. They will look bulged on the top an may be a little leaky (brownish stain).

If you see this problem, you can buy a new power supply at www.shopjimmy.com or ebay. You will need the make and model, of your tv to order! Good luck, I hope this is helpful!!

Mar 24, 2009 | LG 42LG50 42 in. LCD HDTV

1 Answer

Lcd tv


Hi!

Sounds like you have a bad power supply board! This is not hard to do yourself, as long as you are somewhat handy! Take the case apart (back side), and look for some bad caps (capacitors) on the power supply board. They will look bulged on the top an may be a little leaky (brownish stain).

If you see this problem, you can buy a new power supply at www.shopjimmy.com or ebay. You will need the make and model, of your tv to order! Good luck, I hope this is helpful!!

Mar 08, 2009 | Sharp Aquos LC-46D62U 46 in. LCD HDTV

1 Answer

27'' LCD panel compatability


Both power supplies are supplying the same voltages to the circuits but in order to use the one from the NS-27LCD 27" you will need to change the wiring configurations to make it work for the LCT2715..
I could repair the power supply from the LCT2715 for under $90.00 including parts, labor and shipping it back to you.
Let me know if you require further assistance.

Mar 01, 2009 | Flat Panel Televisions

5 Answers

NEED A AC POWER ADAPTER


Had same problem. Found brand new power supply that is original part from website below:

http://www.encompassparts.com/products/?PWW302-AD13D-03

It was about $100 w/ shipping. Took about 4 days to receive. TV works again!!

May 28, 2008 | Audiovox FPE3000 30 in. HD-Ready LCD...

2 Answers

Akai TV with Megmeet power supply


Hi artoo
if you want you can fix the power supply. i know service tech who fixed my tv power supply. His email is jah2mil@hotmail.com.

Apr 10, 2008 | Akai LCT3201AD 32 in. LCD Television

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