Any luck replacing a CF-31 screen?

We’ve run into a weird issue with the CF-31 where the display stops working if the screen cable is disconnected and reconnected. We’re following all the proper procedures; disconnecting the AC adapter and removing the battery, removing the hard drive, holding the power switch to make sure there’s no power running through the laptop, making sure we’re static free, handling all the internals with great care and surgical precision. All that stuff, yet the problem is consistent. We ran into the issue when doing a screen replacement, but we’ve also duplicated the issue with working screens just by disconnecting and reconnecting them. Depending on which part is failing, this could be getting really expensive really fast. Has anyone else had this problem? Anyone have a solution?

 

I have not experienced that.
Other than getting one in that the previous owner replaced the lcd cable and inserted it backwards. LCD end...Shorted things out. Blown fuses....Sad as it was a 100 hour machine..I ended up getting it and reworked a mk2 board to fit in the housing. Blew out motherboard and lcd panel.

Mk1 and mk2 are not direct swappable.

Are these standard models or ATI graphics models?
What mk are they?

It is VERY easy to insert that LCD cable end in upside down.

 

I asked our lead tech, Marisa, if there was any chance she inserted the LCD cable upside down. No chance, and I believe her because she spent about 5 minutes explaining her procedure to me.

Got the model numbers of three units this happened on. All are MK2, one has ATI graphics but the others do not.

CF-31JLGAX1M: Win7, Intel Core i5-2540M 2.60GHz, vPro,13.1" XGA Touch, 320GB(7200rpm), 4GB, Intel WiFi a/b/g/n, TPM, Bluetooth, ATI Discrete Graphics, Single Pass (Selectable), No Drive, Toughbook Preferred

CF-31JEGAX1M: Win7, Intel Core i5-2520M 2.50GHz, vPro, 13.1" XGA Touch, 320GB(7200rpm), 4GB, Intel WiFi a/b/g/n, TPM, Bluetooth, Single Pass (Selectable), No Drive, Toughbook Preferred

CF-Q5AAX1M: Win7, Intel Core i3-2310M 2.10GHz, No vPro, 13.1" XGA Touch, 320GB(5400rpm), 2GB, Atheros WiFi b/g/n, No TPM, Bluetooth, Lightweight Battery, Single Pass (Selectable), No Drive, Toughbook Preferred

 

The 100 hour unit was a $1000 mistake to me,that hurt. The new cable was not labeled and I had a 50/50 chance, the dealer got blackjack and I got 23.

So are the units dead after that or just the screens?

 

Have you tried connecting to a second display?

I'm seeing some multiplexer issues...or something. Undefined as yet.

Trying to use Linux to diagnose.

Code:

xev

dmesg and etc.

I realize this is difficult if the screen is dead.

 

I thought I had changed the names to protect the innocent..

 

Guilty as charged......ouch

 

Are those LCD are brand new one or a used one. I've changed and swapping the lcd so many times but it never happen to me. On the LCD pcb part near the connector. Follow the circuit power line, check the fuse and may be blown out.

ohlip

 

That's what I'm thinking.

 

"but we’ve also duplicated the issue with working screens just by disconnecting and reconnecting them"

not clear on if you are replicating the problem with the same unit but with different screens ... or ...
different units with the same screen .

also ...
are the screens toast after the replacement attempt or does cycling the machine correct the problem ?

the cmos line drive buffers (say , enable and dim ... etc .) are awful fussy if they are floating .
even the B+ lines that are cmos driven (aka : switched on) can be popped if there is no termination/load on them ...
in some cases , these devices are problematic because they are not protected at the source driver but rather depend on a protection device (say a resistor to ground or clamping diodes) at the device being driven (not a great design) .

i have a couple of other ideas but will wait for the answers to my question(s) .
(one involves the integrity of the cables)

 

Here's what our technician Matt says:

we tried several screens on several units. We would take on from a working unit and put in on one that the screen was not working correctly and it wouldn't work and then when we try putting the screen back it wouldn't work in the original screen. We have tried restarting the machines, removing the battery and adapter and holding the power button for 30 seconds before plugging it back and and trying again and the units still will not display anything on the screen. Now the unit that was originally working will not work with the original screen or the screen from another computer that is working. The screen part numbers are all the same. The screens were swapped between the same MK units, MK2 to MK2, MK1 to MK1.

 

Does the 31 use the separate inverter (led driver) that is part of the touchscreen board, Or is that the CF53 I am thinking of? Probably the 53.

Fire up---NO NO NO I mean start one don't light it on fire.
If you DO light one on fire, please post the video.

Anyway, start one and grab a bright flashlight. Can you see the image with the flashlight shining at the screen?

Trying to narrow down if this is a signal problem or a backlight problem.

I still think this is a cable insertion problem..
Upside down or not far enough.

Do you have another one to test out?
Try swapping the entire top. or at least lcd and cable. Remove the cable from the motherboard end..

 

Matt: "We tried replacing the Touchscreen board as well but the screen does not directly plug into it at all. The 53 does though I believe you were thinking about the CF-53 like you said. Using a light does not have any effect at all."

Matt: "We tried replacing the cable, and it is not in upside down and is inserted all of the way. We tried moving LCD and cable with the same problem."

 

Ok.
Hope everyone understands I am not trying to insult anyones work. This is just so bizarre.
I can be just as absentminded as anyone. Once I wanted to replace the AC cord on something with a longer one. Too bad I forgot to unplug it first. Thank goodness for my Klein diagonals with the well insulated red grips.. Bzaaap..What happened to the lights?

Is there any static electricity? Carpeted floor?

Just trying a process of elimination.

Just had an idea. Plug in an external monitor and see if that works. If it does, get into the BIOS and see what the monitor is set at. Internal/external/both. I forget the exact terms. I had one that drove me crazy until I discovered the internal monitor got switched off.

 

yeah ... pretty hard to insert the connector upside down , especially if one leaves that kapton seal tape on the connector or uses a magic marker .
as shawn said , check the bios ...
it might be that for some reason (way above my pay grade) , once the display is removed/disconnected it is translating into a "nobody is home --- default to monitor on boot up" .
i do have a '31 that i can check this theory out with .

but this raises the question : if it defaults to the external monitor ... it won't show when you boot into bios .
perhaps that upon entering the bios the instruction set includes turning on the lcd and/or the monitor port .

 

We know you're not trying to insult anyone. I apologize if our tone came across as defensive. I can understand how this could be frustrating for you guys as well, and I want to assure you that we are reading and considering all your suggestions.

Matt: "The floor is concrete not carpet and we always make sure to discharge any static electricity before opening the computer. The computer will come up on an external monitor but it doesn't matter if it is set to internal or external it still will not come up on the screen, we tried that before but I tried again just to make sure and still no results."

 

odd ideas to ponder. Reaching I know...

Voltage of power supply.
BIOS version
ATI into non ATI unit.
A seemingly innocent movement is shorting out and causing stored current to blow a fuse. Metal tools? Jewelery
Maybe the actual swapping of the lcd is not the problem. Review every step of the shutdown//powerdrain procedure.

Michael Faraday's ghost is haunting your shop....

 

sooo ...
in theory ...
if i take the display/lid of my '31 apart and disconnect the connector from the lcd and reconnect it , i should wind up with a seemingly dead screen ?
or do i have to actually use another lcd/display ?
jussst making sure .

ps ... i am leaning toward mr. murphy .