Inspiron 15 5000 series - detects led panel only after BIOS reset

[Rigo]

G'day folks,
Got this one in to replace the panel.
First replacement panel didn't give a sign of life.
Bought a second one and was about to declare that one faulty as well then realised the screen actually flashed at start-up then went black like nothing there. So this one might something in it but maybe the problem is somewhere else.
When the LED is not detected the HDMI port works fine to an external monitor. OK.
Accidentally discovered that resetting the BIOS enables it to pick up the LED at start-up.
Some times on warm boot it might lose it (requiring BIOS reset again) or still handles the LED ok. Totally unstable, cannot trust it.
When it detects the LED the external monitor might come on as well or not, unpredictable.
When the LED is not detected the external monitor works without fail.
Customer wants to use it as portable to school so desktop replacement not an option.
Updated the BIOS to latest, no difference.
Actually difficult to reset the BIOS as a side note. Removing the batteries and holding the power button in for 60 sec not guaranteed to reset, try again.
Yes, I've reseated and checked the video cord - looking all ok.
Questions:
1) - Is it 2 panels out of 2 new ones faulty? (different vendors).
2) - Motherboard level problem?
Thank you folks for any input.
PS: Been dealing lately with some time consuming cheap jobs that were supposed to be straightforward swap and go How do price these when quoting?

 

[gadgetfixup]

Your post is all over the place but are you sure you don't have a bad cable?

 

[Rigo]

Your post is all over the place but are you sure you don't have a bad cable?

Yeah, I'm all over the place myself!
The cable looks ok, no sign of damage anywhere that I can see but I'll have to get one to swap and check. So don't know

 

[nlinecomputers]

Its the cable or the motherboard. What was the issue with the original panel?

 

[Rigo]

Its the cable or the motherboard. What was the issue with the original panel?

It was cracked she said.
Removed initially by some other tech who put on a 30-pin dead screen to it, this one takes a 40-pin with touch features.
When I opened it indeed the cable was simply stuck with sticky tape next to the screen connector socket.

 

[nlinecomputers]

So it’s possible that the dumbass tried to force a 30 pin into the socket and blew the cable and or mobo.

 

[Rigo]

So it’s possible that the dumbass tried to force a 30 pin into the socket and blew the cable and or mobo.

Quite possible.
Can't understand how you can open the thing to get there and not be able to source out the correct part to complete the job.
Well, I didn't ask her whether she rejected his quote for repairs which might explain this odd case

 

[Porthos]

Removed initially by some other tech

That is where I refuse to work on it.

 

[Rigo]

That is where I refuse to work on it.

Well, I didn't know until I opened it then asked questions.
Was only told on receipt that the other guy didn't have the correct part at hand. Thought odd that he couldn't try to get it but there again how would she be able to explain why I thought.
I said I didn't stock screens but just order them in as needed and she was ok with that.

 

[nlinecomputers]

It doesn't make much sense. If you did order the wrong part why would you not return it to your vendor? As the client, I would not pay for the wrong part. If Mr. Pizza Tech ate it then that is a painful mistake.

 

[Rigo]

It doesn't make much sense. If you did order the wrong part why would you not return it to your vendor? As the client, I would not pay for the wrong part. If Mr. Pizza Tech ate it then that is a painful mistake.

No, he didn't bother ordering one.
The original was cracked so he replaced it with a dead correct size one but the socket was not right, so he just sticky taped the video cable next to it. Don't know whether he did try plugging it in.

 

[nlinecomputers]

Why would you put a dead panel in the unit?

 

[gadgetfixup]

Ah now it's making more sense since we know someone plugged a 30 pin cable into a 40 pin screen. Sounds like what you're seeing is the blacklight being enabled on the proper screen but no image. My guess is he blew the filters on the motherboard for the screens data lines. Practically all data lines have small filters that will blow in a split second if any significant voltage is applied to them. Stabbing a 30 pin cable into a 40 pin screen would almost definitely put blacklight voltage down a data line. You only need to lose one data line to lose image.

 

[fincoder]

What I don't understand is why someone would try connecting a spare screen that had the wrong size connector. I mean it would obviously be wrong as soon as you put the plug near the socket. It's idiotic to continue plugging it in anyway expecting a miracle to happen!