Samsung UN55HU7200 not powering on, no blink code

[jason123]

Re: Samsung UN55HU7200 not powering on, no blink code

Looks like a replacement main board did the trick. Working fine now.

Wonder if it's an EEPROM thing. Here is what's odd, the board I received booted with Korean Language. Which is odd, since the supported languages are French, English and Spanish Only. Wonder if the seller installed a replacement EPROM from Korea / China?

I was able to revert back to English.. but I thought it was odd.

[nomoresonys]

Re: Samsung UN55HU7200 not powering on, no blink code

Check over the powerboard solder joints real closely.

[vinceroger69]

Re: Samsung UN55HU7200 not powering on, no blink code

have you got any freeze spray i wonder if its worth freezing the nand and see if the set starts up.

[jason123]

Re: Samsung UN55HU7200 not powering on, no blink code

I tried disconnecting the panel 1 ribbon at a time, I disconnect Main to TCON, one ribbon at a time.. no impact at all on the behavior. It's doing the same thing; no backlight, and just relay clicks every 15 or so seconds. Seems it's in a reboot sequence.

[neilc6]

Re: Samsung UN55HU7200 not powering on, no blink code

What happens if you disconnect one side of the tcon at a time? If backlights turn on with main board disconnected and no video with either side disconnected, I would suspect tcon.

[jason123]

Re: Samsung UN55HU7200 not powering on, no blink code

I disconnected wifi and bluetooth modules, no bootup. I pretty much repeated what was done, and all i get is a relay click every 15 seconds or so

[vinceroger69]

Re: Samsung UN55HU7200 not powering on, no blink code

Hi there.. did you ever figure out the issue? I am having the Exact problem with my set.

disconnect the wifi card and see if the set will start up then.

[withalligators]

Re: Samsung UN55HU7200 not powering on, no blink code

Hey Jason, never solved it. Pretty sure it wasn't the mainboard. I ended up with not enough time to do a full teardown to check the LEDs, but that would have been my next step.

Good luck, and if you do figure it out I'd love to know.

[jason123]

Re: Samsung UN55HU7200 not powering on, no blink code

Hi there.. did you ever figure out the issue? I am having the Exact problem with my set.

[dskall]

Re: Samsung UN55HU7200 not powering on, no blink code

I was only commenting on post 28 that a panel can have shorts that will keep tv from coming on.

[withalligators]

Re: Samsung UN55HU7200 not powering on, no blink code

Rats. So is that what I probably have? Never encountered it before. It's always been obviously the panel or fixable. Or a bad LED.

[dskall]

Re: Samsung UN55HU7200 not powering on, no blink code

Bad tab bonds are generally opens. By putting pressure on them you are reconnecting them. You can have shorts on panel boards etc. that can take out your t-con and shut tv down.

[withalligators]

Re: Samsung UN55HU7200 not powering on, no blink code

OK. With no blink code? Would there be any symptoms? Is there any way to test that? I ask because I've had many TVs with bad tab bonds that were either fixable with thermal pads or a totally lost cause. But they turned on and functioned, just with a bad picture.

[dskall]

Re: Samsung UN55HU7200 not powering on, no blink code

A panel can prevent turn-on if it is shorted which is usually tab driver or panel board. Cracked screens usually don't short they have opens.

[withalligators]

Re: Samsung UN55HU7200 not powering on, no blink code

Interestingly, while plugging in the old board, I noticed that if you press the little reset button on the main and the big relay on the power board clicks, the indicator LED also turns off as if the TV is powering on. Then a second later the light comes on and there is another relay click. If you hold the button the shut off action is delayed til you release it.

[withalligators]

Re: Samsung UN55HU7200 not powering on, no blink code

Right, I've already shipped the kit back. After that, I bought a different main board off ebay from a unit that was working but had a cracked screen (purportedly). It was for a different (but allegedly the same) model, the 55hu7250 (mine is the 7200). I gambled on it because it was much cheaper. Inspecting it, it's a little different. It's missing the little reset button (or whatever it does, I can't figure it out) and missing a little soldered on bumper. I thought that was enough to indicate that the board was indeed different, but now, after some close examinations of ebay boards, both variants appear to be both with and without the button and bumper. Now, I'm wondering if the board is incompatible, or if there is something insidious and hard to diagnose wrong with this TV. Like something simple like a bad cable somewhere.

If the backlights come on by disconnecting the main and power, that indicates they are fine, right? Could there be something wrong with the actual LCD panel? I don't see how that would prevent a turn on. I've had cracked tvs still turn on and work fine otherwise.

[dskall]

Re: Samsung UN55HU7200 not powering on, no blink code

Yes I would like to know how a Wi-Fi module will keep a tv from turning on. I know it happens. Iv's seen the posts. I wish someone could give technical explanation as to why.

[brucetv]

Re: Samsung UN55HU7200 not powering on, no blink code

I've gotten bad boards from SJ before and their return process is fast and easy. But since you bought the kit you will need to ship the whole kit back. It's possible you have a bad panel as well. I suspect you just got a bad main board with that kit. Your led's are fine if they are coming on when you have the cable disconnected from the main. These days sometimes it can be something stupid like a bad Bluetooth module or Wi-Fi module causing the Tv not to turn on.

[withalligators]

Re: Samsung UN55HU7200 not powering on, no blink code

Guys, there's no way it's an LED, right? I don't have to worry about taking apart the panel? The backlights couldn't come on, period, correct?

[withalligators]

Re: Samsung UN55HU7200 not powering on, no blink code

Welp, I gambled on the cheaper board, the BN94-07777A, from the 55hu7250 version. No dice. Same exact symptoms. So either they're not compatible, or something is wrong in the panel. Luckily I bought it in an auction for 34 with shipping. Sooo, should I just buy the right board and sell the other one, right?
Cheers