Samsung LN40A530P1F - Shuts off from time to time

[Dgtech]

This set had already been recapped but the failure continues. I was told that it would shut down from time to time.

Checking this power board, there are two components that I'm not sure of. These two green components are hotter than crap and may be close to a thermal breaking point. There is no significant voltage drop across it AC or DC, so I'm guessing it's a current component. These heatsinks get pretty warm as well. Like remove finger after five seconds warm. I need to know how to proceed. You can see also that the two green components have gotten hot enough to change the board color a little in that region. They have resistor markings on the board in their position.

[PlainBill]

Re: Samsung LN40A530P1F - Shuts off from time to time

Thermistors. They normally run hot.

PlainBill

[billansor]

Re: Samsung LN40A530P1F - Shuts off from time to time

I could not see if there was a cap in the board that has shrink tubing around it. I have had a few of these come in with the tubing and the caps were bad from excessive heat build up.. The caps that had the shrink tubing insulation were small values.

Check the inverter transformer with a flyback checker to see if any are breaking down. An old flyback checker like sencore 48 would work.

Just a couple of ideas

[Dgtech]

Re: Samsung LN40A530P1F - Shuts off from time to time

Thanks for the help guys.

The heat shrunk components are inductors.

I still have a bad feeling I'm chasing down a temperature related problem. The heatsinks are warmer than I'd like them to be. This set has not shut down since I got it from the person that complained about the problem. The difference is that I have the back off and it's in my garage/shop, which is cooler than normal. Maybe it's getting the ventalation to barely keep it going without a problem. This sucks!

I'm thinking about ordering a replacement board just to see if these are normal temps. Intermittent problems are the worse. I take that back, samsung is the worse.

[billansor]

Re: Samsung LN40A530P1F - Shuts off from time to time

A thought to consider;

Do not use a hair dryer as it will not sufficiently mimic self contained heat... If you have a harbor freight tool place near by, get the 1000 / 1500 watt heat gun / stripper.

This heat gun stripper will literally heat components in a way that will cause an intermittent shut down to occur rather quickly. This heat gun does not have a high velocity blower on it but it is steady and brings heat up very nicely in a specific area. It will maintain the heat for a longer period than a hair dryer does.

You do have to be careful but everytime I have used this heat gun, I have been able to get to the problem.

Just an idea

Bill

[Dgtech]

Re: Samsung LN40A530P1F - Shuts off from time to time

I took a break from fixing tv's and got some house projects done this winter. I now only have this one TV left.

I changed the power board and got the same result. I can turn it on and watch it for a long while, about an hour, then it will turn off by itself. Sometimes it will stay off and other times it will just reset and come back.

I have no clue how to proceed.

[Scenic]

Re: Samsung LN40A530P1F - Shuts off from time to time

This sounds kinda like the problem I had with my LE40A536.

Even the series are similar
L = LCD
E/N = Europe / North America
40 = size in inches
A = year 2008
5 = series
30/36 = submodel


My guess is that the mainboard failure starts out like what you're currently seeing, and it continues to worsen up to the point where it behaves like the trashed mainboard I had, which would restart the TV every 10-15 seconds no matter what.

http://www.youtube.com/watch?v=xlfDREBcevs

I'd say unless you can grab a used working mainboard cheap (like I managed to, even though it wasn't exactly cheap), that thing is pretty much gone.
Selling the PSU board(s?) and the LCD panel or looking for a 40" TV with a cracked one (preferably a similar samsung) is about the only thing you can do.

[Mike95inNJ]

Re: Samsung LN40A530P1F - Shuts off from time to time

I garbage picked this same tv last summer and had a similiar problem. Mine would run for 10-15 minutes then I'd lose the video on it. I recapped the PS with slightly higher voltage on the caps and it "appeared" to be working. A few weeks went by with it working fine and all of a sudden the problem was back. No video but sound was fine. Power it off and back on and it would continue to work. It appears to be a heat issue in my case. I'm going to save up for a refurbed PS. For now I modded a fan into it to blow on the area that gets the hottest and it works fine. Mine does'nt power off it when this happens. I did'nt mind cutting a hole in it since I'm going to keep it for personal use in one of our bedrooms. They even threw out the remote with it.
Good luck with yours.

[Scenic]

Re: Samsung LN40A530P1F - Shuts off from time to time

^ I did a similar fan mod on mine, but mainly because the PSU runs so ridiculously hot you can easily burn your fingers on the heatsinks (don't try that while it's running.. they're live)

Mine now has an 80mm fan running at ~3.5V at the back where the VESA holes are.
It's fed from an adjustable voltage regulator on a piece of scrap PCB, which in turn is fed by a switched 13V output of the PSU.

The tiny bit of airflow that thing produces already made one heck of a difference. The PSU is now running about hand-warm

[tibimakai]

Re: Samsung LN40A530P1F - Shuts off from time to time

I have purchased a LN32B530xxx and it worked for a month and a half without an issue, then restarted two times.
At this point I have recapped the PS and I still have to see if the issue it's still there or it will come back.
This was the issue stated by the seller when she sold the TV to me.

[senndogg]

Re: Samsung LN40A530P1F - Shuts off from time to time

there are several restart issues. but the best theory i want most to believe is that the bad caps corrupt the flash/eeprom in the main board. somewhere replacing the caps work, somewher no. i am in a situation like this where the tv doesnt restart in 15secs or minutes but in 2seconds. i am blaming the flash in the main board.

[senndogg]

Re: Samsung LN40A530P1F - Shuts off from time to time

can you try something for me? what happens when LVDS is disconnected?

[Mike95inNJ]

Re: Samsung LN40A530P1F - Shuts off from time to time

^ I did a similar fan mod on mine, but mainly because the PSU runs so ridiculously hot you can easily burn your fingers on the heatsinks (don't try that while it's running.. they're live)

Mine now has an 80mm fan running at ~3.5V at the back where the VESA holes are.
It's fed from an adjustable voltage regulator on a piece of scrap PCB, which in turn is fed by a switched 13V output of the PSU.

The tiny bit of airflow that thing produces already made one heck of a difference. The PSU is now running about hand-warm

That sounds pretty cool. Mine is a usb fan that has to be plugged in on a separate power source because the only usb port on the tv is the service port and I was afraid to try it out plugged in there. Don't want to chance ruining a board. If you get a chance sometime do you think you could post some sort of instructions how I could wire mine up like you did? For me pictures work the best. I'm pretty limited on my knowledge of this stuff.
Thanks and good luck.