Samsung eu75nu8000 no picture after tape method

[PNI E.]

Hi guys, I write here for help me. I have a Samsung eu75nu8000. The Tv start to turn off and on, and I understand it was a panel problem, because if I take out a ribbon the Tv stay on. I tried the tape method but I have no picture but the Tv now stay on. My question is I have to give up because it s the panel? I notice that the chip vpm2sm it s really really hot, I can’t stay with my finger on it. Do u think all the problem of my panel is due to this chip, or u think it s a death panel and I can’t do nothing?sorry for my English

[Diah]

vpm2sm are DC to DC converter.. mean the output circuit it feed had short.

[PNI E.]

So I can’t fix it if with the tape method doesn’t work and the screen is all black?

[Diah]

you need to find out the short, its about caps or essd diode on panel buffer boards if not at gate way transistor inside the screen glass, or also some one play with set before you and did damage the LVDS cable between MB and Panel.

[PNI E.]

So the chip is getting hot because a short after him, I have to find the short on the panel buffer. If there I can fix, but if the short is inside the screen glasses transistor I can’t fix right?

[Davi.p]

ue75nu8000... the right code
post a photo where it's visible where is that hot chip.. i guess it's not the panel..
post also a photo of the entire back view with the boards..
if there is a separate tcon, and the tcon "processor" is of BGA type, try by yourself or with someone help to keep pressed that BGA, then turn on TV and see if image appears.. better to do it after you freezed that chip / board..

[PNI E.]

Thanks for the answer, I’m from Rome, I see you are from Milan. The Tv model eu75nu8000txzt. The chip that become hot is vpmwsm, I show u the board, tell me what I need do and I do….i signed in yellow circle the chip that become hot. Tell me what I need to do. If u want I can write u in Italian

[Davi.p]

Hi, the model starts with UE, not EU.. well, the chip you marked is the PMIC that controls the various power rails to the panel, i'm surprised in a 75 inches there is no separated TCon, shame on Samsung, disgusting.. now the first thing you have to do is to remove the metal.plate bars on the bottom that hides the panel strip boards, on those boards you have to check every bigger capacitor for short circuit, there are also very small diodes or diode packs, if there is no short neighter on them, then locate an eventual U shaped junction flat cable, detache it one side, then plug the power cord and see if the boot loop stops and maybe searching between TV stations you hear the sounds..

[PNI E.]

I’m back guys, I know I’m your nightmare but I really want try to fix my Tv. So here my test. The Tv do NOT turn on with both the flat cable in. Do not turn on also if I plug off the U flat on the little boards on display. If I plug off one of the flat cable from the main board to the display, then the Tv turn on with sound backlight on but no images. The thing I don’t understand the Tv turn on if I plug off the right side panel flat, but works also if I do the opposite, if I plug off the left flat panel and plug on the right the Tv start on, so don’t care with flat cable I take off, the Tv with just one flat right or left plug in turn on with sound and back light on but no image. I notice if I plug the right flat panel the chip vpm2 is more hot.

davi.p I did what u asked me and I test all the capacitor on the little board on the bottom of display. I put the tester in beep mode and I had some capacitor that sign in short, I make the photo. The capacitor beep have a resistence of 2,5 ohm I don’t know if it s normal…If someone can help me it will make me really happy. I give u the photo of the test of capacitors so if someone tell me what to do I follow.

davi p are u Italian?

[Davi.p]

Those 0,9ohm caps sounds a bit strange, maybe is a misread.. have you tested with main board detached from panel? What could be do is to locate on the main board the two common test points that when connected together disables the protection, so you can test the voltage on the TCON part of the main board, but most of all on the panel caps... i think i know where we will end, i tell you what i think i discovered, the reason why no matter which ribbon you detach the tv stays on is that it is not the panel at fault but the main board.. by detaching half panel you unload a certain amount from the main processor (well.. the only processor) that is heavily oxydated.. so if you want to try this test., but i don't know if is effective, you can freeze the CPU or the entire board, then turn on the TV pressing the chip and asking someone to watch the screen...

PS: Sono italiano mi chiamo Davide..

[PNI E.]

The capacitor I tested with the flat plug in, if I unplug the flat cable I don’t have more beep from the tester on the capacitor. So u are saying me to try to freeze with the cold spry the cpu ( I call cpu the main processor ) then press on it and turn on the Tv. If I have for some second the video, it means the panel is ok and it s a main board problem. Am I saying all correct.

[PNI E.]

I freeze the cpu and press it and try if I see the video I give u the photo of the cpu, and where are the point I have to connect

ps ciao Davide sono Fabrizio grazie per l aiuto

[Davi.p]

I cannot locate the two test points, the board markings are not readable, do as follow, use multimeter in continuity, check between the 2 most inner pins of the connectors for the flat cables that goes to panel, if them are connected, check also between the outmost pins (with the panel inserted), if are connected, then you can try connecting a very slim wire between these last two, so you can check the panel tensions... ok but.. these tests are not mandatory, because you already confirmed you have no shorts in panel boards... the real test is the one on the cpu, i confirm you have understood it..

[PNI E.]

Come back after the test that suggest Davi.p. I freeze the processor, the Tv start but after 4 5 sec turn off. Always backlight on and sound, display without picture all black no strips nothing, just black. What I notice is if I put a finger on the cpu a part become very hot, hot that u can barely have finger on it, I don’t know if it s normal. I show up the part that become hot. Do you think it s a main board faulty? I have hot air gun can I try to remove the cpu, but I never done,,,,if I remove and try to resolding do I think I can fix or I have to try to buy a new one

[Diah]

FB_TRDY 1 and FB_TRDY 3 are feedback points... search after them on yours MB close to LVDS socket

[PNI E.]

FB_TRDY 1 and FB_TRDY 3 are feedback points... search after them on yours MB close to LVDS socket

Thanks for your help, when I find this point what I should do…sorry I’m not a professional, but if u say me what I have mesaure I can do it, thanks

[Diah]

Thanks for your help, when I find this point what I should do…sorry I’m not a professional, but if u say me what I have mesaure I can do it, thanks

normally we jumper this 2 points together.. so the MB will learn there are panel connected... so you can disconnect one LVDS at time or also one U ribbon.... to check picture how it look to know which side defect.... but i have doubt too you will see any picture because you have short make the IC very hot to touch. give try

[PNI E.]

normally we jumper this 2 points together.. so the MB will learn there are panel connected... so you can disconnect one LVDS at time or also one U ribbon.... to check picture how it look to know which side defect.... but i have doubt too you will see any picture because you have short make the IC very hot to touch. give try

Really thanks I give a try and let you know, but at this point I think it s the cpu in short not the panel, there is a way to test the cpu?

[Diah]

Really thanks I give a try and let you know, but at this point I think it s the cpu in short not the panel, there is a way to test the cpu?

dont touch the Soc right now,,,, to know if the short at the MB... disconnect the 2 LVDS from MB side and turn on... check the IC temperature

by the way why you removed the heat sink of it ?

[PNI E.]

dont touch the Soc right now,,,, to know if the short at the MB... disconnect the 2 LVDS from MB side and turn on... check the IC temperature

by the way why you removed the heat sink of it ?

I follow what Davi.p said me. He said me to freeze it with the ice spray, and press it and turn on and try if I had video, but unlucky I didn’t have nothing, I mean the Tv turn on 5 sec with audio, backlights on but screen all black. And I notice the cpu hot, and the freeze there gone very very fast. But I didn’t try without the lvds disconnected….i try and say u.