Question Screen LCD Flickered, now dead, Plz help troubleshoot

Thunder Bay

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Guys/Gals,
Screen flickered like crazy for a couple minutes, now LCD is dead. Computer starts up fine, power light, HD/fans, etc. HP Envy 15" (2015). I get nothing, not even an LCD blink on start-up. External HDMI doesn't work so I can't use that. This seemed to come on hours after a Win10 update when I was looking at some pictures on a website, then it started to flicker and act up. Can you help with next steps??

What I've done:
1) Tried another known good LCD screen that I had (old spare). It worked for a few minutes unscrewed from the case. I shut down, screwed it in the case, restarted and nothing since, even after multiple restarts and power drain. Tried wiggling the cable, doesn't seem to make a difference. Can't see an image using a flashlight either. I know this screen was working before.

2) Disassembled & Removed backup battery, reset DIMM, quadruple-checked cables and LCD cable. (fully seated). Everything looks normal inside.

3) Restarted with and w/o laptop battery multiple times

4) I just ordered a new cable to try when it arrives. But something tells me it's driver-related.

Any other thoughts, ideas? Things I can try? Is there another way to clear the bios? Or start in safe mode w/o going through the Win10 multi-step process? I'm running 'blind' here.

Thanks a million!!
 
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Thunder Bay

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Sorry, I wrote it, network dropped out, then I couldn't find the original post to finish. My apologies.

So ...anybody have ideas how to proceed next with this dead screen issue??

If I don't get even a flash of "HP" upon start-up after turning on, does that point to a hardware issue? (not driver)

Thaks
 
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Thunder Bay

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Ok, brand new HP LCD cable arrived, tried it with 3x LCD screens that were working before all this happened. No difference. Tried Win+B to reset bios (it sounded like it went through the steps). I also tried a different stick of RAM. Nothing. If I let it run for a couple hours, the chips in the circuit board along the bottom of the LCD don't get warm at all. During normal operation in the past they'd get warm. How would a guy determine if it were motherboard hardware problems?

Again, laptop seems to start as per normal. HD light flickers, I can hear it read. Sounds like it normally would. All lights come on, sounds like normal. Just no LCD display (ever!). Not even a blink or HP splash. HDMI hasn't worked in a while so can't use that (that was a driver issue I believe). The last driver was a microsoft driver which overwrote an intel driver. Any other troubleshooting steps you can think of to determine if it's hardware or not ...while running blind? Thanx
 
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Thunder Bay

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Update:
I made a Bios Recovery USB, it went through it's paces, restarted a couple times. Still not even a flicker or glimmer of backlight with either of the screens I believe to be 'good'. LCD cable is definitely fully-seated (new cable). Sounds like it's starting up fine. Restarted a few times, no difference. It was a good idea. Anything else you can think of?

LCD chips aren't getting warm either. I'm wondering if there is some inherent motherboard issue on this PC that finally just gave up? I've gone through a few screens with it in the last 8 months. Note: I almost never close the laptop ..sits at a desk 95% of time. I'm somewhat tempted to replace the MB, or maybe time for a different unit, huh?

Thank you
 
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lga1156_ftw

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So let me get this straight, the laptop has killed multiple LCD panels before this already?
Thats super rare and should not happen if there is no defect in the lcd circuit. What is the exact motherboard model its written on it somewhere.
 

Thunder Bay

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I can't say this laptop was burning out screens. I just happened to go through a few LCD's in the last 2 years. The original LCD flaked out after about 4 years. The problem on that one seemed to be the circuit board connection below the LCD (you push in a certain spot the LCD would work ok). That seemed to be a mechanical issue. I bought an ebay replacement (used), which after 4 months that one went bad. It displayed a lot of lines and then went out IIRC. It was used, I don't know the history of the LCD. I then bought a brand new LCD that has lasted a year until this problem recently.

As it is now I don't know if the current LCD is bad or not. It could be. I put in the original working LCD (ok I didn't tell you but I received a LCD from an ebay sell that had a bunch of spots so he sent another one out). That screen worked when I started it up. But after a few minutes it too started blinking and flashing, and I figured I would do a restart and the LCD (neither of them) ever lit up after that.

So, I don't believe it was the MB blowing out screens. I can't rule it out either. Maybe all the LCDs I have now Are in fact dead ..I can't say. Or they may work (??). How would a guy know if it were mb h-ware problems? What symptoms would a guy see if it was bad video hardware on the MB?

Here are some numbers I see on the MB:

763585-501
DC1520
Printed on motherboard: DAY33AMB6C0 Rev: C

Thanks
 
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zx128k

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If you get no power or picture to the laptops builtin monitor then its a troubleshoot you need access to the laptop to complete.

If the laptop boots like its working then I would try an extrenal monitor as that can sometimes work if the builtin screen has failed.

If the backlight is dead, you use a light like a small torch and shine it on the screen you can sometimes see a picture. Sometimes its no backlight voltage, light is dead or a cable issue.


If you can't see a picture, then you are troubleshooting a no picture issue.

 

lga1156_ftw

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Can you pls check that the external hdmi port is looking fine from the outside, look that the pins are straight?
Its not "driver" related hdmi failure you should get picture on external if lcd screen or cable is failing.
 

Thunder Bay

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Thanks guys.
I tried the flashlight (on the screen) trick several times before (I've done it on LCD TV's before). I was not able to see anything. The HDMI pins aren't bent. The issue I believe on that is the driver. When I did a bios reset (a month or two ago) it reset back to the bios which didn't support HDMI. Afterwards I was not able to find the updated driver on HPs site but the PC worked ok as it was. It was on my to-do list to find/update it but this screen issue beat me to it. I tried the HDMI again recently and it doesn't work. I've used the HDMI to troubleshoot screen issues in the past. Can't do it on this one unfortunately.

Thanks again. I appreciate you all taking time to walk me through various ideas.
 

lga1156_ftw

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Try to disassembly until ytou see cmos battery, look for this round battery : https://www.aliexpress.com/item/32841073098.html
Remove it and put it back after 10mins.

In HP laptops sometimes key combination is needed to switch between monitors its FN + F1-12 , one of the F keys has the symbol.

You can also try to ´boot the laptop "barebone" meaning remove cmos battery, wifi card etc , literally everything but the motherboard itself, put it in non conductive table and try to boot it with power cable ( no press of power button or the power button board is needed since cmos battery is removed )
 

Thunder Bay

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I tried the "remove the battery trick" a while ago, but I can try it again since I reinstalled the bios yesterday. And try the HDMI again after that.

Thanks
 

lga1156_ftw

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Some high resolution close up photos of the lcd connector (as well as other connectors) would be nice to see and also the motherboard from both sides without any tapes.

Since you updated bios also pretty close before this happened there might be still few things to try like reflashing the bios chip on the motherboard.

IF it is this model : https://www.aliexpress.com/item/32841073098.html

The chip is located between the round hole in the pcb and small heatsink, its 8 legged soic
 

Thunder Bay

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Ok guys Partial VICTORY!! We have disply (although washed out and interlaced). I did a combination of:
  1. Removed the CMOS battery for at least 1/2 hour (I did not do that after reinstalling the bios)
  2. Moved the RAM to a different slow
  3. Ensured proper LCD cable connections. Don't laugh, but I think on the previous 2 removals, installation of the motherboard I may have put the new video cable in upside down (Stupid me) ..because parts are out of the case. I don't know for sure, but I think I did.
The old video cable doesn't work. That must have been at least part of the problem. I tried swapping it back/fourth a couple times. HDMI is working again.

Now, the laptop LCD display is heavily washed out and interlaced. Any ideas what cause that? I tried a number of things, and reseating the cable a few times. The pins on the connectors look good, not damaged. It's Intel 4600. I went to Intel's site and it says I have the latest video driver. All other drivers/software seem to be up to date. Bios is latest. Image looks perfect via HDMI. I'm not sure if there's a setting I should toggle, or what? Both LCD panels I have appear washed out and interlaced. It's set to 1920x1080, 64hz refresh. You can see color settings below. Maybe you can see the vertical lines in the last (close-up) picture, and the text is heavily pixelated. I wonder if the new cable is faulty(??). It was brand new HP supposedly.

Thanks for getting me this far. Any ideas on the screen issues would be helpful. I'll post pictures. Thanks guys. You've all been a tremendous help and I truly appreciate it!!

[FIXED] https://flic.kr/p/2iVnwrD ]View: https://www.flickr.com/photos/153586552@N04/49830731647/in/album-72157714078470151/[/FIXED]

[FIXED] https://flic.kr/p/2iVkRSL ]View: https://www.flickr.com/photos/153586552@N04/49830406796/in/dateposted-public/[/FIXED]
 
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lga1156_ftw

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Like i said before there Is no driver issue with the hdmi and it should work like it did. Bad lcd cable might of killed the previous lcds. If you get those lines only on internal screen its still cable Or connector issue, do not buy new new lcd, you can try inspecting the connector More carefully and reseating it on lcd and mobo side
 

Thunder Bay

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Thanks. I appreciate the response. I think you're probably right that its between the m-board and the LCD. I will inspect the connector with a jewler's loop, but I have reseated several time and no difference. If after inspection, I'll get a different cable and see how that goes.

Cheers...
 

Thunder Bay

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Ok new info:

Not sure what happened but after I inspected the connector pins with a jeweler's loop (they look fine), and reinstalled the keyboard, one of the chips on the mobo started to smoke. I know which one. Dang! I could probably solder in a replacement, but at this point I'm probably going to buy a new PC or replace the mobo. Man, I (we) were SO close. On this computer HP Envy 15T-K100 i7 (4710HQ) quad core, is there a better/faster chip/mobo that will fit in this (if I decide to replace the motherboard)?

Thank you very much!
 

lga1156_ftw

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Did you remove battery and power cable before disconnecting Or connecting anything? If you did and nothing was shorted when you powered it on this was defect on the mobo. Can you sen pic from the affected area?
 

Thunder Bay

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I did, but it occurred 30 seconds or so after being hooked up to power/battery. Not sure what caused it, I wasn't monkeying around with it at the time it fried. No sweat, water, or objects were on the circuit board. Wasn't touching it. It was fully mounted in the chassis with all cables connected. I've had the board in/out a dozen times. Actually never had a laptop board fry out. Lucky day I guess ..and it's MINE ..ha ha. Obviously something was amiss that fried it, but it wasn't like it was a response to something I was doing at the moment. I do some work on radio and TVs, I've caused the smoke to come out of a few components over the years.

I don't have a picture of a circuit board, but it melted the top of chip 011 (or Q11?) about an inch from the speaker plug (topside of the board), near the fan hole. Looks like some sort of power transistor(??). The pc won't turn on now. With the battery attached that chip gets hot. If I was going to repair, I'd just buy a used mobo for $130. Haven't decided what to do. PC is 2014 so not that new. But been a good machine overall.

But I might just buy another PC (probably used ...a couple yrs old).
 
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lga1156_ftw

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Burning components means that there is probably short somewhere, so replacing only that chip wont probably solve the issue. Thats why it would be really nice to know what is it, this would point to probably cause of it.
Either read with a magifying glass what is the model of it from top of the chip, if it looks burned out drop some isoprophyl alcohol on it, that makes it sometimes easier to see small text, If the modelnumber is burned off look near chip there will be something like PQ62 or R68 , i can check with that code what chip is it from schematic.

This might of been pure coincidence also its a 6 year old laptop motherboard, anything can happen to these things.
 

lga1156_ftw

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Before getting new motherboard you have to be sure it was THAT causing the issue, i have seen shorted components kill motherboards before. I mean keyboards, usb hubs, lcd panels etc, im still wondering was some of the problems caused by the motherboard or example broken connector on the mobo.

Used motherboards for this model look fairly cheap around 100$ cheapest ones, this might actually be good idea if we get to the bottom of it.
 

Thunder Bay

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Thank you guys, I really appreciate your help and dedication to this project. Anything we can tease out would be helpful. I'm still toying with buying a replacement mobo. Even though the PC is a bit on the older side, it ran great on Win10 and was more or less rock-solid and worked great for my needs.

I should mention that I believe the first LCD panel may have failed due to mechanical causes: One of the screws on the cover had broken away at the hinge b/c I believe HP had the hinge adjusted too tight (IMO) -- that little undetectable flexing on the bottom of the LCD circuit board I believe damaged the initial LCD panel. This was a 'refurbished' computer to me. Once I noticed it, I loosened the hinge tension and repaired the damaged lid mounting screw. I believe that flexing may have caused the original screen to fail as pinching the circuit board in the corner by the hinge would make the screen operate properly. Just what I noticed, I didn't investigate the original LCD board.

Here are the pictures (last one is video connector). The chip in question is marked: A9YA 4X. Any thoughts you can provide would be helpful. Thanks again!!

[fixed] https://flic.kr/p/2iVGcQC ]View: https://www.flickr.com/photos/153586552@N04/49834376192/in/dateposted-public/[/fixed]

[fixed] https://flic.kr/p/2iVEDv8 ]View: https://www.flickr.com/photos/153586552@N04/49834072301/in/dateposted-public/[/fixed]

[fixed] https://flic.kr/p/2iVGdX7 ]View: https://www.flickr.com/photos/153586552@N04/49834379932/in/dateposted-public/[/fixed]
 
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lga1156_ftw

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PQ = power transistor, and Q11 means its transistor. You could try remove LCD connector, keyboard connector, USB hub connector, speaker connector and then boot up to see if it boots. First try without HDMI if you get power light and HDD activity, then shuttdown, connect HDMI and try with that.

DO not plugin the LCD cable at all.
 
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