Samsung LN40C500F3FXZA Will Not Turn On


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Samsung LN40C500F3FXZA Will Not Turn On

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jay78
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Sep 3, 2012, 4:19 AM

Post #1 of 14 (3969 views)
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Samsung LN40C500F3FXZA Will Not Turn On	Can't Post

Hi all,
Thanks for reading my post.
My Samsung LN40C500F3FXZA died this weekend. It is only 1.5 years old! It worked Friday, but Saturday would not turn on. The red status LED is on, solid. There is absolutely no response to pressing power on the remote or on the face of the TV. Samsung's website troubleshooter tells me that it "needs service." No kidding.
I did some reading online, then took the back off and looked at all the boards. I cannot find any visible damage, blown capacitors or fuses, etc. Can anyone offer help on how to diagnose / repair this unit?
Thanks again.

jay78
New User

Sep 3, 2012, 4:01 PM

Post #2 of 14 (3956 views)
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Re: [jay78] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

I bought a service manual and did some voltage meter checks this morning and I need some help interpreting the results. For instance, the manual says: Does proper Main DC B12V, B13V, B5V appear at TP - B12V, B13V, B5V?
There are no specification ranges in the manual, so how do I know what is "proper"? In this case, the 12V circuit tested out at 13V. Is that a failure or a pass? (I assume it fails but don't want to buy parts on that assumption!)
Also, the manual advises to "Check the output voltage of SMPS", but it doesn't have any specifications for the output voltage. Does anyone have these to share?
Thank you for your help.

(This post was edited by jay78 on Sep 3, 2012, 4:03 PM)

74f100
Enthusiast

Sep 5, 2012, 1:37 AM

Post #3 of 14 (3938 views)
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Re: [jay78] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

No, 13vdc on a 12vdc line is normal.
HDMI not working

74f100
Enthusiast

Sep 5, 2012, 1:57 AM

Post #4 of 14 (3937 views)
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Re: [jay78] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

You are right,,,,another case of a drunk monkey writing a manual.

Look for the a5v going from the power supply to the main. You should have this, you have a standby light. But confirm anyway.

Then go to pin 2 of FNC101, this is the on pulse. It should change when you press the power button (touch pad in your case). But take note of what it reads BEFORE trying to turn it on. If it reads 0 vdc when in standby, it should go up to at least 3.3 vdc when turned on. If it doesn't you need to check further on your main.

That should be enough to get you going, I'll be out of the loop for most of the rest of the week.

Good luck,
Jim
HDMI not working

jay78
New User

Sep 6, 2012, 2:48 AM

Post #5 of 14 (3920 views)
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Re: [74f100] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

Thanks for the reply.
I can confirm a5v is working.
Pin 2 of FNC101 is 0 V at all times. There is no change when the power touch pad button is pressed.
Based on some advice I got previous to to your post from a parts supplier, I have a main board in the mail. Should arrive tomorrow. I'll post, success or failure.

74f100
Enthusiast

Sep 6, 2012, 3:23 AM

Post #6 of 14 (3918 views)
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Re: [jay78] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

Yep, I agree on the main. That line should change (usually high) when power is pressed.

Good luck,
Jim

PS. I have gotten bad mains, if it doesn't work don't assume it is another problem. Just re-check the same voltages and check points.
HDMI not working

jay78
New User

Sep 7, 2012, 3:27 AM

Post #7 of 14 (3902 views)
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Re: [74f100] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

Success! Main board it was. When I swapped the boards, I noticed a small burned spot next to one of the tiny surface mount devices behind the HDMI jack on the old board. Many thanks to Jim, and also to Ben over at Retechtv.com, who helped diagnose the problem and got me a replacement main board for a great price.

Unfortunately, the HDMI output of my directv box is out. I checked it with a couple different cables and then connected other devices to the TV to prove the TV was ok. I'm assuming the TV failed and took out the box or vice versa. The box is fine otherwise, and I'm running on component cables for now.

Directv has a new box shipping out to me. Its a HD DVR model. Anybody know if you can just swap the hard drives? (so I don't lose all my recorded content)

Thanks again. I never would have guessed I'd get this thing working again for <$75! (Board and service manual)

(This post was edited by jay78 on Sep 7, 2012, 3:29 AM)

74f100
Enthusiast

Sep 7, 2012, 11:17 AM

Post #8 of 14 (3898 views)
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Re: [jay78] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

It was the box that took out the TV. I've seen many of these this year. So many I wrote an article on the subject.

Way to go!!!!
HDMI not working

jay78
New User

Sep 7, 2012, 1:00 PM

Post #9 of 14 (3896 views)
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Re: [74f100] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

Interesting! I'll search for that article later, but if you have a chance, can you send me a link? I'd like to find out if I can protect myself from this happening again.
Thanks!

74f100
Enthusiast

Sep 7, 2012, 1:45 PM

Post #10 of 14 (3894 views)
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Re: [jay78] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

The direct link is here: http://www.squidoo.com/hdmi-not-working

With a satellite you won't be able to isolate the co-ax cable. It will block the satellite signal from the box, but disconnecting the RF in cable to the box when storms are going on will provide some protection. That's all contained in the article.

BTW, don't try reconnecting that box HDMI. It may not have blown the main on the TV this time, but if left connected it will.

Good luck,
Jim
HDMI not working

jay78
New User

Sep 8, 2012, 1:24 AM

Post #11 of 14 (3887 views)
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Re: [74f100] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

Thanks for the info on the HDMI. I've left the HDMI disconnected for now, until the new box arrives.

jay78
New User

Sep 16, 2012, 3:55 AM

Post #12 of 14 (3832 views)
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Re: [jay78] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

Turns out that my HDMI cable got zapped too! Directv box, cable, and TV, all damaged at the same time!

74f100
Enthusiast

Sep 19, 2012, 4:19 AM

Post #13 of 14 (3818 views)
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Re: [jay78] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

Yeah, that's why I tell anyone that has that happen to replace the STB at a minimum.

Glad it all worked out!
HDMI not working

pmhstar
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Oct 6, 2013, 9:52 PM

Post #14 of 14 (3246 views)
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Re: [jay78] Samsung LN40C500F3FXZA Will Not Turn On [In reply to]	Can't Post

We have the same problem with this set - red light on but set not responding to remote or power button. Problem started yesterday & either red light would flicker when the remote was pressed or just stayed on. After numerous attempts set powered up and otherwise was fine. Today it will not come on. I opened box and checked PS caps that look OK & back side of board also OK. Backside of Main board had orange/white rosin corrosion marks all over - I cleaned and replaced board but same problem. We are in US Virgin Island & very humid all year.
Does someone have service manual so I can troubleshoot?
Any suggestions on where to get Main board if this is the problem? USVI serviced by USPS.
Thanks in advance for your help.

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