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LCD Power Problem - Not Capacitors

by 4993toeternity / February 26, 2010 4:49 AM PST

I have a Samsung LN40A500 purchased about 14 months ago. My problem appears very similar to many others but is just a little different. While watching it the other night it powered down by itself and the red light on the power button started blinking steady. Attempts to turn it back on didn't do anything - no noise, no change, no picture, no sound. The light continued blinking steady until we went to bed. In the middle of the night we heard the power-up tone and it appeared to be working fine. Shut it off and went to bed. The next morning it turned on fine, no noise, no delay. After about 20 minutes it started screeching and the picture became green "noise." We powered it off, gave it a few minutes and tried again. This time it worked fine for about 30 seconds and did the same screech and green screen. Powered it off and let it rest and it would not power back up and the red light resumed blinking steadily.

I checked the capicitors as recommended and they all looked fine. I went ahead and changed out the 2 25V 470uF caps with 35V 470uF caps since I had already bought them. Plugged it back in and same thing - no noise, no clicks, no picture, no sound, just a steady blinking red light.

Can someone please offer suggestions on what to try next? I have NO electronics experience but can figure most things out if explained well (like the capacitor replacement was on this forum).

Thanks for any help you can offer!

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LCD Power Problem - Not Capacitors
by Samsung_HD_Tech Samsung staff / February 26, 2010 8:27 AM PST


If you register online and you're a U.S. customer, you can get an additional 3 months of warranty coverage on your product.

You can do that here:

I don't know if your unit will be covered since opening the unit usually voids the warranty, but see if they will help repair your unit after you register online by calling 800-SAMSUNG.


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3 month ext warranty
by werthr / February 26, 2010 7:17 PM PST

Thank You! this is exactly what I needed. You saved me from badmouthing Samsung. Now I can get my 'turn on' problem fixed on my LN40A550P3F LCD HDTV. One question though. I have already made arrangements with Samsung to repair my TV. I am 140 miles from the nearest repair place (Rapid City SD) They were reluctant to come to me because they mentioned Samsung may not pay them mileage. I agreed I would deliver the TV myself to be repaired. Will Samsung at least pay me the actual cost of my gas to get my TV there? Thanks

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3 month ext warranty
by Samsung_HD_Tech Samsung staff / March 11, 2010 6:41 AM PST
In reply to: 3 month ext warranty


You can ask service, but that would ultimately be between you and them. Good to hear that you're able to get your set fixed.


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Still could be the caps/eeprom may need to be reboooted.
by robotecg / February 26, 2010 11:11 PM PST

I saw an article on a site that said just because the caps look good doesnt mean they arent bad. Also, it is necessary to boot the eeprom on some sets by shorting pins 5 and 6 in order to get it to turn back on after replacing the caps.

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shorting pins 5 and 6
by 4993toeternity / February 27, 2010 3:18 AM PST

Thanks a bunch for the reply and link. Since this is my first trip inside a circuit board, could you please be more specific on how to find eeprom pins 5 and 6 and how to short them?

Thanks Again!

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eeprom-pins 5 and 6
by robotecg / February 28, 2010 12:06 AM PST
In reply to: shorting pins 5 and 6

Follow the link I posted. The thread has detailed info as to where to find the pins and how to short them. There are a series of buttons to push on the remote after plugging in the TV. Good luck.

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Samsung is repairing certain out-of-warranty LCD tvs.
by dholmes10 / March 25, 2010 1:00 PM PDT

My Samsung 40" was occasionally turning off and back on by itself and I knew about the bad caps issue. I decided to call Samsung and they said if it was a bad capacitor problem, they would repair for free. Well, the service people they sent out brought a power supply that didn't even work when it was installed in my TV. They then said they would have to take the TV in for testing. I got suspicious when they said that. Anyway, service manager called later and said the panel was going bad. Now, I'm no TV expert, but would the occasional turning off and back be caused by a bad panel? I thought a bad panel exhibits lines on the screen. I suspect the service shop was trying to change out a good part.

The service guy told me to call Samsung executive services and plead my case and get them to extend the warranty as a gesture of goodwill. I was able to get them to extend my warranty for six month and they then replaced the panel for free.

I still wonder if they were just feeding me some bs with replacing the panel so they could recoup their labor charges for the on-site visits.

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Power issue could've caused other damage.
by robotecg / March 25, 2010 2:37 PM PDT

I've heard where the power problem caused damage to other components.

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Found My Problem
by 4993toeternity / March 25, 2010 10:46 PM PDT

I ended up taking my set in to a shop. Turns out the problem was a bad inverter that subsequently fried the video board (card?). I'm not sure exactly what that means but that is what I was told and it's working fine now.

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Glad you got it fixed
by DeXXX27 / June 19, 2010 12:09 AM PDT
In reply to: Found My Problem

My tv is displaying the same exact symptoms that you described. so i'm sure i can same services done but not quite clear about the problem parts. so they had to replace two parts(new inverter;new board)according to them at least? cuz i haven't bothered looking inside my tv but since you described my problem to the dot more than anything i really just wanted to know how much the these guys ended up charging you. your posts alone is relieving since now i have hope for my tv yet.


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What seems to be the problem?
by Muroso / January 15, 2011 6:25 PM PST

We have the same exact model and have the same problem. it turns on and off and sometimes when i plug it in there is a loud screeching noise coming from the back of the tv. exactly what you just said, sometimes in wont do this but it keeps powering on and off until the right display comes on till i turn it off again. did samsung manage to fix the problem? so is it bad capacitors also? i open the back of my tv and the capacitors doesn't look like there bad. so im wondering what seems to be the issue with your tv? thank you so much!

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What is the Capacitor number and wats for Samsung LN40C630K
by medikonduri / August 11, 2011 11:40 AM PDT

Hi All,

My tv is not responding suddenly when i'm watching it. the red light on the power is on and it is not turning off also. So I had gone through the forums and want to so soldring work as i just passed warranty period. does any body knows what is the capacitor number and wats information on LN40C630K tv.

Btw I called samsung customer care for the first time and they told they can repair it for free. but later when I send the reciept and recalled them they told it is not possible to offer free service. shame on samsung for putting junk parts and cheating customer.

If any body knows what is the capacitor number and wats information for LN40C630K.

Thanks in advance.

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If you google (research) more.
by R. Proffitt Forum moderator / August 11, 2011 11:59 AM PDT

The markings are on the CAPS.

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CAPS are good
by medikonduri / August 11, 2011 2:26 PM PDT

Hi Bob,

I just opened my LCD back dome to make sure CAPS are good. and they all are good. so don't know what may be the issue. Need to check what samsung team will tell regarding my service request they need 24-48 hrs to review a ticket.


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Same Issue
by StuckFloJo / September 20, 2013 9:43 PM PDT
In reply to: CAPS are good

Hey Mohan,

what was the outcome?
I am having the exact same symptoms...and all caps seem to be ok.


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