Samsung UN55D6450 turns itself off and on endlessly, no blinks

[withalligators]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

@ Johnboy1313 Yeah, if you decide to go into the panel and let me know how you did it, that would be awesome. I'm still very reticent to damage this thing accidentally. If it turns out I need them, I'd love to buy your backlight strips!

@mmartell, thanks for that link, I'm going to go test them as soon as I can, I'll get back to you about the LVDS cable, but as far as I remember, you just squeezed the sides to release it.

@splitcrete: I agree, I paid way too much, but it was bought from a friend who was sort of desperately down on his luck. I would never have bought it off craigslist for that much. It was more a little bit of charity in disguise.

[johnboy1313]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

@ Johnboy1313 Yeah, if you decide to go into the panel and let me know how you did it, that would be awesome. I'm still very reticent to damage this thing accidentally. If it turns out I need them, I'd love to buy your backlight strips!

I was going to cut the tape with a razor. The screen is already fubar'd. If it helps any, I'll try to see if I can carefully peel the tape back to save the adhesive. Maybe it can be resealed.

[withalligators]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

@johnboy: That would be fantastically helpful!

@mmartell: My LVDS connectors are much simpler than the one in your thread. It's 2 pushtabs on the side and that's it. Sorry.

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

My lvds cable mystery is solved. There is a tab that must be flipped up first (exactly like the one's on the other side of the tcon) before you can squeeze and extract.

[withalligators]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Good, luckily you didn't break it trying to figure it out. I've been there.

I also tried to jump the LED backlights using the guide posted by Tom. I couldn't get anything to light at all, which worries me that it's not simply an LED strip failure. I suppose I could try replacing the power board first, but it's hard to get readings on this thing because it turns itself on and off all the time as soon as you plug it in.

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Ya small victory on the lvds cable, lol.

Refresh my memory, does your PS cycle even with everything disconnected from it ?

[withalligators]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

no, with the main board unplugged, it doesn't cycle.

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

How about an audible "click" on power up ? I don't even see a relay on my PS and don't remember if it made any clicking sound when it was working properly.

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

NM I see in your earlier posts you make reference to the clicks. AFAIK with these power supplies the relay should click when plugged in with no load. Mine does not. Hmmm..

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

I also tried to jump the LED backlights using the guide posted by Tom. I couldn't get anything to light at all, which worries me that it's not simply an LED strip failure. I suppose I could try replacing the power board first, but it's hard to get readings on this thing because it turns itself on and off all the time as soon as you plug it in.

I just realized I haven't measured the voltages that lead to the led strips with the inference that if the voltages are there and there is no light then I myself will be looking at prying the panel apart to get to the strips.

I'm guessing you tried simply removing the PS <--> MAIN cable and pkugging the set in to see if that fires your backlight ? (If the .pdf didn't apply to you, too)

[tibimakai]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Ones I had a similar issue. I have removed the PS_ON wire from it's connector and I have measured it and it was cycling. I ended up replacing the mainbord.

[withalligators]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

If I plug it in to AC with the power to main cable disconnected, there is a slight relay click. Then there is another about 5-10seconds after I unplug it. If I plug it in to AC with everything connected, the same relay click is audible, but then there is a much louder one everytime the backlights cycle on and off. Then, after I unplug it, there are continual relay clicks that lessen in intensity and increase in interval as the PS discharges over the course of maybe 20-30 seconds.

If I disconnect the main, the unit does nothing when I plug it in. I can get power throughout the board on different points, but I have no idea what I should be getting without the main connected. I do get the same readings across every transformer and cap on the inverter section of the board though, whatever that means.

[johnboy1313]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

withalligators and mmartell, I will be opening this set back up tonight and stripping it for parts. Let me know what measurements you need and I'll get the readings for you.

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

I have the D6000 variant with a single 4-wire connector leading to the led's. I'm not sure how these are constructed so I wouldn't even know what measurements to ask for. But I am curious as to what this looks like inside

The four wires seem to be broken down into 2 pairs. One pair of wires measures a short. Not sure if that's normal or not.

[mmartell]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

withalligators and mmartell, I will be opening this set back up tonight and stripping it for parts. Let me know what measurements you need and I'll get the readings for you.

Oh and take pics !!!

[johnboy1313]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

I've got it on my "bench" dining room table right now. There is no careful removal of the tape. It is stuck down firmly. I had to slice the tape with a razor. Before I strip this. I'm going to see what can be done to reassemble it and power it on.

[tom66]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

6000 and 6450 should be similar in construction, maybe one has different smart features or main board.

[johnboy1313]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

The tape surrounding the perimeter of the bezel needs to be peeled from all four sides to expose more screws.

[withalligators]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

Again, after you get it open, and I can repeat the process, I'd like the backlight strips from you. I don't know how else I'd ever get any, so getting them from you would be amazingly fortuitous.

Edit: I typed this before a ton of replies but didn't press post. This is awesome! I'm glad there are some screws holding it together under that tape. So, the tape might be a little structural, but it's probably to prevent light leakage, eh?

[johnboy1313]

Re: Samsung UN55D6450 turns itself off and on endlessly, no blinks

In some spots it's way easier to just remove the tape where it covers the screw head.