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Old 05-04-2019, 12:05 AM   #1
Brucetafer
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Default samsung un55f7100 clicking led flash

I can't seem to keep a tv running in this house to save my life..

tv will run if i leave it off overnight, turns on and stays on all day, unless I turn it off and try to turn it back on, it just clicks and clicks and the leds flash until i unplug it..

Checked all the voltages they are in spec when its clicked on, and then 0 when clicks off..

Checked the LEDs with my tested and they are all working and not drawing out of range.

When I unplugged the main board and turned it on it flashed even faster maybe 2x as fast if that means anything..

I have a 47 inch 7150 tv boards but I don't think they will work for this..

I checked all the caps and carefully looked over the board for burn marks and bulged caps but no luck at all..
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Last edited by Brucetafer; 05-04-2019 at 12:15 AM..
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Old 05-04-2019, 12:57 AM   #2
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Default Re: samsung un55f7100 clicking led flash

What kind of LED tester are you using? Most LED tester only puts out about 30mA, not enough to drive the LED hard enough to cause bad LED to show up.
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Old 05-04-2019, 12:40 PM   #3
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Default Re: samsung un55f7100 clicking led flash

I would check your ps voltages when the backlights are flashing to see if they are stable. Supply voltage cutting out to the LED controller could cause them flash.

https://www.badcaps.net/forum/showth...682#post871682

Last edited by neilc6; 05-04-2019 at 12:44 PM..
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Old 05-04-2019, 02:13 PM   #4
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Default Re: samsung un55f7100 clicking led flash

Im using a 300v 10 amp bench power supply to drive them, CC was the same on each led strip.

what's weird is it turned on this morning and works perfectly, turned the brightness all the way up and no dead spots or hot spots..

I have a 5 digit bench multimeter rms, and all voltages are stable, its either 0 or within spec.
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Old 05-04-2019, 02:16 PM   #5
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Default Re: samsung un55f7100 clicking led flash

Quote:
Originally Posted by neilc6 View Post
I just read through your post, did you ever figure out for sure what the problem was? the cheapest power supply I found wasn't cheap.
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Old 05-04-2019, 02:25 PM   #6
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Default Re: samsung un55f7100 clicking led flash

https://www.shopjimmy.com/samsung-bn...repair-kit.htm

would this be a start?
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Old 05-04-2019, 02:31 PM   #7
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Default Re: samsung un55f7100 clicking led flash

Oops, reply to the wrong thread.

Last edited by budm; 05-04-2019 at 02:33 PM..
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Old 05-04-2019, 02:31 PM   #8
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Default Re: samsung un55f7100 clicking led flash

I just bought a new board in my case. Tough to debug intermittent problems. Cold solder joints could cause intermittent failures so I would inspect/reheat the ones around the transformer and diodes.
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Old 05-04-2019, 02:37 PM   #9
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Default Re: samsung un55f7100 clicking led flash

Quote:
Originally Posted by neilc6 View Post
I just bought a new board in my case. Tough to debug intermittent problems. Cold solder joints could cause intermittent failures so I would inspect/reheat the ones around the transformer and diodes.
what did you pay? all i see is like 150-250
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Old 05-04-2019, 03:16 PM   #10
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Default Re: samsung un55f7100 clicking led flash

Here's a cheaper one. I have used a buyqual subsititute board before and had no problems.

https://www.buyqual.com/samsung-bn44...pply-unit.html

Looks like shopjimmy has a repair kit as well.
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Old 05-04-2019, 05:30 PM   #11
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Default Re: samsung un55f7100 clicking led flash

Quote:
Originally Posted by neilc6 View Post
Here's a cheaper one. I have used a buyqual subsititute board before and had no problems.

https://www.buyqual.com/samsung-bn44...pply-unit.html

Looks like shopjimmy has a repair kit as well.
thanks man, Ill do both just to see if i can repair mine and sell it..
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Old 05-04-2019, 07:08 PM   #12
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Default Re: samsung un55f7100 clicking led flash

ok, Its on now, checked the voltages and everything is in spec.. where should I start probing?
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Old 05-04-2019, 09:12 PM   #13
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Default Re: samsung un55f7100 clicking led flash

What is the board P/N? BN44-?????
I would check the output Voltage of all 5 boost converter to see if one or all are fluctuating or not.
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Old 05-04-2019, 09:28 PM   #14
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Default Re: samsung un55f7100 clicking led flash

Quote:
Originally Posted by budm View Post
What is the board P/N? BN44-?????
I would check the output Voltage of all 5 boost converter to see if one or all are fluctuating or not.
BN44-00629A

Ill check right now
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Old 05-04-2019, 09:38 PM   #15
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Default Re: samsung un55f7100 clicking led flash

ok, im retarded, what and where do I look? Im trying to check the voltages on everything and write them down
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Old 05-04-2019, 11:39 PM   #16
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Default Re: samsung un55f7100 clicking led flash

Quote:
Originally Posted by Brucetafer View Post
ok, Its on now, checked the voltages and everything is in spec.. where should I start probing?
Quote:
Originally Posted by Brucetafer View Post
ok, im retarded, what and where do I look? Im trying to check the voltages on everything and write them down
What do you mean "checked the voltages and everything is in spec.." but then you ask "what and where do I look?"
BTW, the LED connectors have label for each pins so just measure each pin (with connectors still in place) when TV is on.
NC = No Connection (or Not Connected).

Last edited by budm; 05-05-2019 at 12:18 AM..
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Old 05-05-2019, 04:01 PM   #17
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Default Re: samsung un55f7100 clicking led flash

Quote:
Originally Posted by budm View Post
What do you mean "checked the voltages and everything is in spec.." but then you ask "what and where do I look?"
BTW, the LED connectors have label for each pins so just measure each pin (with connectors still in place) when TV is on.
NC = No Connection (or Not Connected).
sorry, was trying to say, the posted voltages on the power supply are all correct when the tv is on, tried measuring each pin for the LED plugs,

LED plug 1

5 - 32v
7 - 1.56
9 1.06
10 - 65v
11 65v
13 66v
16 1.77
17 1.93
20 32.1
21 66v
24 1.02

LED plug 2
2 62v
3 63v
6 32v
7 130
10 130
14 66
15 63
18 130
19 32.8

24 pin

1 13v Actual 12.86
3 13v A 12.82
5 OD_LED 2.84
7 OD_ON 2.94
9 GND
11 13v Actual 12.86
13 13v Actual 12.84
15 Vamp 12.84
17 Vamp 12.84
19 GND
21 5v Actual 5.35
23 5v Actual 5.36

Whats driving me nuts is it turns on no problem after sitting a while, I can turn it off and on 3-4 times in a row and then it goes into the clicking cycle.
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Old 05-05-2019, 04:07 PM   #18
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Default Re: samsung un55f7100 clicking led flash

I think you have open and shorted LEDs on the Backlight strips.
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Old 05-05-2019, 04:37 PM   #19
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Default Re: samsung un55f7100 clicking led flash

Where are the pin names for the LED connectors? They do not mean much witout knowing the pin names to go with the readings.
You have the board in front of you but I do not.
BTW, if you tun down the backlights level (not brightness) to as low as you can on all inputs, will the TV come on and works fine every time?

Last edited by budm; 05-05-2019 at 04:42 PM..
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Old 05-05-2019, 07:07 PM   #20
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Default Re: samsung un55f7100 clicking led flash

Ive tried to get it back on with no luck.. I drove the LEDS line by line

L1 27.5v
l2 56.5
L3 56.5
L4 56.5
L5 27.5

R1 27.5
R2 56.5
R3 56.5
R4 56.5
R5 27.5

I have a basic LED tester from amazon/ebay, and tried my best to see if all the LEDS were firing, which they looked good with the screen not removed..

im sorry bud, I took the picture but i guess i didn't upload it! sorry!! ill post it now
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