Re: Westinghouse WD55UDR101 4k LED TV Control Board Failure
Any change if you disconnect the backlights?
Kilroy2k1
Senior Member
Last Activity: 11-04-2023, 09:04 AM
Joined: 08-16-2009
Location: Ontario Canada
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Re: Samsung UA55EH6030MXSQ Bad LCD Display
Could be a bad cap or resistor on the panel driver boards.Leave a comment:
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Re: Samsung UN65JS8500FXZA - Screen goes black when smarthub is plugged into TV
Could be in the TV or a short in the cable itself....Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
Glad you have it sorted now. I posted the datasheet of the diode array so you could replace it if you want.
Little tip on these sets, turn the back light down about 15-20%,reduce the brightness and contrast down a few percent. Those 2 resistors that showed the pulsing will thank you.
Enjoy.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
You can take a pair of side cutters, warm the chip up with your soldering iron and try to snip the top off it as if you were trying to decap the chip (removeing the top layer)
Then with the plastic package mostly broken you should be able to get to and heat the rest of the bits to desolder them.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
The flux would help but you can do without.
Theres a flex cable 1/2" away from the diode, just dont flick the hot diode on to it.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
Wide tip is better for removal, make sure the tip is clean and use a fair bit of flux, get it in there on one side of the chip, preferably away from the flex cable, cover as many of those visible solder pads (the 5 connections on one side of the chip i called pins before) as you can and then feed it extra solder and flux, when its to temp it'll just slide off like nothing. Dont rush it, dont push hard, let the heat do its thing.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
And if you really want to change it, here is some info on the diode array....Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
Ignore the resistors for the moment, they are likely getting hot due to the diode.
yes you should be able to remove that diode safely and test the tv.
With your pencil iron get an overabundance of solder on it and it'll come off with the added thermal mass of the extra solder.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
Burn that bridge when you get to it. No point in asking whats after the next step when you havent done the next step.
Dab the fluid on the components a small section at a time and watch the area closely while it power cycles.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
Any update on the status?Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
If you have some very high percentage rubbing alcohol you can use that in place of the lighter fluid. It has to be 95% or better because water will conduct and fry bits. Only draw back is it evaporates faster.
I prefer lighter fluid, its safer due to the lower evaporation rate and it is non conductive.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
Any corner store should have small bottles of the lighter fluid for zippos.
I dont recall if they were in parallel but its entirely possible. At the time I didnt know what the component was so I had no idea if the shorted pins were just shared pins or if it was actually shorted. The Lighter fluid put that guess to rest and pointed out the exact component to pop off..
Oh, and I think someone pointed out, yes you can run without the diode and even without some of the caps. but...Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
I pointed to the diodes as a potential point of fault, I do not recommend just removing them willy nilly without finding the 1 thats faulty.
You can narrow down what side the fault is on by reattaching the flex one side at a time.
Once thats sorted, you can try the lighter fluid method or sharpen your probes and test them, If they test ok then it could be a capacitor. test for a shorted cap as well.
I wish i would have taken video of the one I located the faulty diode on,...Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
Resistors look ok,
On the very outer ends of the boards you see those little black bits that look like 10 pin devices.
Those are Diode array devices. the center pad on both sides is your common, i think cathode (someone please correct me if i am wrong)
Test with a meter set to continuity between the center pad and the other 4 pads. If any show continuity then you have your problem device.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
Just for giggles and squirts, lay it down and pop the speaker off, pop the legs and brackets off then remove the metal strip along the bottom that covers the driver boards and take and post a high res pic of both outboard driver boards please.
And while your there try Nicks suggestion to remove the left and right flex cables....Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
I have to agree here, I have done two of these in the past couple of months. One was the diode and the second one was the resistors ( just repaired it this morning).
I was fairly certain the unit rebooted with the LVDS cables disconnected but I am not 100% sure it was the case so I didnt push the issue.
The second one I worked on only had vertical banding which was the result of failed resistors.
Personally I think it fails because in both cases the tvs were set to Backlights...Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
If you are confident its the main and can make it power cycle, i would switch to the lighter fluid testing. Its non conductive and has a slower evaporation rate then alcohol.
Dribble a bit and use a q tip to spread it around the t con dc/dc converter area and watch for any motion in the liquid as the set cycles. I'f theres any shorted components the fluid will run away from the hot spot.
Continue around all the diff power rail sections till you find the culprit.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
I'm inclined to agree with Davi.p that it is likely a short somewhere on the main board.
Plug everything back in how it should be then let it cycle a few times then feel around the main board for warm areas.
Only feel around the Main Board, Not the power supply board.
***DO NOT FEEL AROUND THE POWER SUPPLY BOARD WITH BARE SKIN OR AT ALL***
I felt it needed to be said.Leave a comment:
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Re: Samsung UN55KS800DFXZA Ver. AA02 with the seemingly common power cycling problem
I have this exact model and had the power cycling issue. Turned out to be a diode on the driver board.
With the TV laying on the bench with the back facing you you'll see theres 4 driver boards along the bottom.
The main board connects directly to the 2 center ones and there are small flex cables attaching the outer boards to the inner ones.
On the left hand one disconnect the flex between boards and then plug it in, see if it power cycles..
if it still cycles, reconnect...Leave a comment:
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