My TV will power itself off after 2 seconds. I opened it up and tested all of the fuses on the power supply board, and they were all good. I visually inspected all of the capacitors and none appeared swollen or leaky at all, except the three very large ones all have white around the base. One of the white puddles has covered a couple resistors' legs. What can i check now to narrow down the problem? How can i test the backlight inverter board?

1. Measure the stand-By voltage if is there on the power supply, if not replace the power supply.
2. If the stand-by voltage is OK, change the main board.

Unfortunately plasma tvs are a lot more complex to service, instead of 2 or 3 boards there are a half dozen at least. I would guess when the main PS board went out it took some other boards with it. I don't have a manual for your set but I would look at the power supply sub boards, there generally are 2 of them, or on some models that is parts of the other boards. Generally there is a legend to see what voltages are supposed to be present at what places, samsung is good about making the test points on the boards. Also there are fuses on most the other boards and its possible one of those has blow, it won't be a typical fuse like your used to seeing, some are a small green component and some are white mini fuses...Good luck!

Replace the inverter, the capacitors on it are bad.

This indicates that the power board, in the TV, is not powering up at all. The quick fix is that it could be simply that the fuse is blown. To access the fuse, you will need to remove the screws on the rear of the TV and remove the entire rear panel. The fuses will be located on the board where the power cord connects. Please do not visually inspect these, but rather use a DMM (multi-meter) to test across the fuse for continuity. If one or more is found blown, then replace with one of the same type and rating from your local Hardware store.

If the new fuse does not cure the problem then, there is a failure on the power supply board inside the TV. Commonly the capacitors on this board will receive a surge and then fail. They can sometimes be visually verified by removing the rear of the set and inspecting them for bulges or leaking fluid at the top or the base of the caps. This is the most common mode of failure for these sets. The problem could also be a cracked solder joint, or failed IC regulator, in which case it would be more cost effective to replace the board itself. The Power Supply Board for your TV is "Modular" meaning that you can replace it yourself without any tools besides a screwdriver.

see this pic this pic is from samsung TV see all the caps that are going to blow just change the caps your tv will be fine

hope that it helped

Power supply board would be first suspect to look at.

some general info:

ISSUES:

1. IF sound main fuse/s are good.
2. If no power or standby check main fuse, standby power supply and any signsof damage you can see---burnt parts etc.
3. almost all these sets the troubleshooting involves checking voltages on the main power board to narrow down theproblem.
4. Be safe and if you do not know what you are doing don't open the set.

Answers to issues:

1. RE:fuses---if a blown fuse is found get a good replacement(not the genericones like Radio Shack). Many fuses are special even aside from amperage--Don'tput a higher rated amperage fuse in the set for any reason.

2. RE: power supply in set: if total dead aside from main fuse the set uses astandby power supply that runs 7/24 and a main supply (some are combined andsome not.

Here aside from checking fuses you want to examine all the filter caps on thepower/standby to see if any are puffed up or buldged up in some fashion--Iattach a photo of a good one---top should be silver metal and PERFECTLY flatand have no brown material coming out on top or bottom.

What happens in the standby area is they use caps with too low a voltage rating(saves money) which causes them to fail in a year or two---the standby runs7/24 and the heat dries out the caps and they fail.

3. Trouble shooting consists of the above and then at some point you have to buyand try a board to see if it fixes it or not.

4. Safety first--no TV set is worth getting injured or even killed over.If set is opened at least look for puffed up and bad caps like in thisphoto.

hi, the first step that you need to do is to check the power supply board this will require opening the back cover of your TV set.once the cover is remove you can immediately see the power supply board this is where the power cord is connected.visually check the components on it remove any bulge deformed capacitors,check the fuses replace the fuse if it is burned.test the power board after replacing the parts.use your multimeter to measure the power output there must be a 12v,5v 24volts present on the output terminal....If this voltages are present then your TV should be working again.....

Please try to open the back cover and look for the power supply board..(it is usually found directly connected to the power cord)..

Then check the condition of capacitors on the power supply visually..
If it is look like leak or bulged try to replace it to fix your TV..

Normally this is indicative of a faulty power supply circuit inside your TV.

The easiest way to test this is to remove the rear access panel on the TV and replace the power supply circuit board with a new one.

You can find a replacement circuit board on Ebay by searching for your TV's model number.

Here is a link to one currently available for about $100 plus shipping:

http://cgi.ebay.com/DPS-178APA-Power-Board-Power-Supply-Sharp-LC-37D43U-/260814504762?pt=LH_DefaultDomain_2&hash=item3cb9c1833a

Just use your mouse to click on the link, which is the underlined and highlighted text just above. This will open a new web browser page automatically for you and allow you to view the information and items at the website indicated.

The repair / replacement procedure is not extremely difficult if you have some basic electrical safety knowledge and some basic electronics / mechanical repair skills.

You will need to unplug the power cord from the unit, lay the TV screen side down on something soft and flat like a bed, and then remove the rear access panel or the entire rear cover as required in order to access the circuit boards inside.

When you remove the rear cover and access the circuit boards inside, just check the part number that is printed right on your power supply circuit board itself and confirm that it exactly matches the one provided in the Ebay listing.

Then unclip and remove the various electrical wire connectors leading to the power supply circuit board. Then remove the screws securing the circuit board to the TV frame and then remove the power supply circuit board. Be sure to avoid touching any large capacitors on the circuit board which can retain a nasty charge even after the unit is unplugged.

Then just screw in the new circuit board and connect all the wire bundles to their appropriate connectors on the new circuit board and then replace the rear cover. Then plug in the power cord and test.

One other thing you can check is to see if there is a fuse fitted on your set.

Some models will have a fuse holder compartment accessible from the rear of the set right where the power cord enters the enclosure. If your set does not have one of these, then the fuse may be located directly on the power supply circuit board itself.

Try testing that fuse for continuity with a voltmeter (with the set unplugged of course). If that fuse has failed, then it will test OPEN. If you are lucky, you may then just need to buy an exact replacement fuse and then install / solder that into place to correct the problem

I hope that was helpful to you, good luck.

Joe.

Ok.. What is the status of the power LED at the front. Does it blink, change color a few seconds after its turned on? Do you notice any clicking noise from the set?

Please provide this info so that we can continue with the diagnosis.
Sai.

Hi,
Please unplug TV from wall socket for couple of minutes, replug back in and turn ON.
If still does not power up, try it in another wall socket.
Also check standby/ power light flashing or its solid at TV.
If standby light is flashing or its not lit then TV got power supply problem and requires qualified TV tech. I hope TV is still under warranty so ask for warranty cover to store.
Thanks.