T42 LCD display goes out comes on after close open lid

[2think]

T42 LCD display goes out within seconds and only comes back on after closing and opening lid. External display stays on ok if set as primary monitor and lid is closed. Just started happening today. Replaced two 512MB memory sticks with 2X1GB sticks a week ago. Pressing along the handrest next to the untraNav does not turn lcd back on so it woulod suggest that it is not a GPU problem. I read somewhere that the GPU problems does not occur with T42 series.

T42-2374JU4 1.7GHz 2G 40G XP-SP2 ATI RADEON 7500 32MB

any clues what is the cause and how to fix?

Andrea

[sjthinkpader]

Could be the inverter or the backlight CCF.

[Harryc]

Could be the lid open/close switch is stuck or defective also.

[2think]

Thanks for the clues. one thing I discovered, pressing the little button next to the left hinge has the same effect as opening and closing the lid. Symptoms presist, lcd goes out within seconds.

I looked for the below parts on system parts and service manual. I found the inverter card shown in the service manual but where are backlight CCF and open/close lid switch? Also what other diagnostics can I perform to verify cause and correct repair?

-inverter
-backlight CCF
-open/close lid switch

Replacing inverter seems to be a serious repair.

[jamerslong]

heres where the real question starts.

when the LCD stops can you see an image on the LCD? you could try shining a light on it to see if you could see anything.

the the answer is yes then it is a backlight issue, this rules out the switch.

if no then it may be the switch or another problem

[2think]

when the LCD stops, I can see an outline of the image on the LCD. Now what?

[SlamX]

Defective backlight.

[2think]

Is LCD backlight same as CCF? I searched for the word CCF in the 260 page Service Manual(SM) and there was not a single instance. I found on P. 70 of SM under system error the term LCD backlight not working. SM states to reseat LCD connector as a first step. Where is the instructions to reseat LCD connector in the SM? Another post pointed to laptoprepair101 suggesting that replacing inverter card fixes this LCD going out problem. I hope inserting this external link is allowed. So does replacing CCF mean replacing inverter card? It is too coincidental that I just replaced memory a week ago- is it possible that I screwed something up to create this problem?

[jamerslong]

I think the CCF is the cable to the backlight. CCF is a type of cable.

I would try reseating everything (it's not difficult, it just involves alot of screws)
if the problem persists replace Inverter.
working on laptop are not to difficult, you just have to be patient and have a large work area with some screw buckets. the HMM has all the information you need.

[2think]

ok, I will open it back up and reseat what I opened. Do I need to reseat this CCF cable for the LCD backlight? Is the CCF cable item # 4 on page 157 - FRU 2030 Replace inverter card on 14.1 in LCD? or Do I perform what is shown on the laptoprepair101 link? By the way, Why does the Service Manual say not to reuse these plastic screws? I do not have another set of screws, will it be ok to reuse these screws?

Thank You all for the guidance.

[jamerslong]

the idea behind not using the plastic screws is because the threads will weaken from installation.

if your carefull you should be able to reuse them, dont over tighten

[2think]

Problem Solved.

While keeping the laptop running with the external display running, I took off the keyboard and verified secure the keyboard connector and memory card (I added two weeks ago). Then I took off the LCD front bezel and checked that the inverter card is secure. LCD was still out. I removed the inverter card and found FRU P/N:26P8464. Same FRU as in my T40. I replaced inverter card with that from T40. LCD is now back on. I did all of this while laptop was running and using my external monitor.

I could not have fixed this problem without your guidance and encouragement. Thank You. The latoprepair101 replace screen inverter was quite helpful too.

Just so I can make sure understand: the reason you excluded the open/close lid switch is the fact that the external monitor stays on, right?

Cheers,
Andrea

[jamerslong]

the switch was excluded because you could still see a display on the LCD, if the switch was the problem the LCD would have turned off with the backlight.
It is common for the external display to stay on when you have the laptop closed. Especially if you have a port replicator on it.

[2think]

How Frustrating. Problem not solved, LCD goes out again after replacing the inverter card. LCD comes back on after close open lid. What next?

[sjthinkpader]

Could be the CCF (cold cathode fluorescine) tube is going out in the LCD. Quick way to check is with another LCD as replacing the CCF in the LCD is a PITA job.

[2think]

Questions, Questions: R u suggesting to take the LCD out of the T40 and swap it with the one in this T42 to verify if it is the CCFL bulb? If it is the CCFL bulb, why does it come on after closing and opening lid? would it not just stay out if it is bad? The lid hooks at the top of the LCD cover are sticking after I reinstalled the front bezel, could these be causing a problem? Moving them left to right does not make LCD come back on.

Does this laptop repair replace CCF accurately describe steps necessary to replace CCF on a T42? Are there better guides or videos?

How common is it for the CCFL to go out in this T4X series?

[sjthinkpader]

Yes, your URL is pretty accurate for replacing CCF.

They have a life of about 3000-5000 hours. Unfortunately most users leave them on or use "screen saver". Nevertheless the backlight was left on which means using up the CCF's limited life.

Using another screen to test it first is the quickest way to make sure it is the CCF going out.

[2think]

Thanks. How about the other two questions:

-If the CCFL bulb is bad, why does it come on after closing and opening lid? would it not just stay out if it is bad?

-The lid hooks at the top of the LCD cover are sticking after I reinstalled the front bezel, could these be causing a problem? Moving them left to right does not make LCD come back on.

[sjthinkpader]

Thanks. How about the other two questions:

-If the CCFL bulb is bad, why does it come on after closing and opening lid? would it not just stay out if it is bad?

-The lid hooks at the top of the LCD cover are sticking after I reinstalled the front bezel, could these be causing a problem? Moving them left to right does not make LCD come back on.

Not quite sure, that's why it is best to try another panel instead of replacing the CCF immediately. The CCF could over current and the inverter shuts down.

No, the hooks just need to be reseated in their slots. The B/L is at the bottom.

[2think]

The T40 LCD is in pieces, I will attempt to put it together to test it in this T42. If unsuccessful, I will need to obtain another. How much should I pay for T42 14.1" XGA 1024x768 LCD?

[2think]

Well. I have yet to fix this T42 LCD that is suspected of a failed CCFL . I have been following the discussion on Guide: How to Replace the backlight in a T4x LCD (soon)

I have a 14.1" XGA LCD P/N 11P8351 FRU 11P8352 with the LCD cable assembly FRU 91P6786 tape attached. Are any other parts off T40 necessary to replace T42 LCD? I came across this replace DIY Notebook Screen Replacement. The article mentions needing glue for the bezel. Is glue necessary? what other cautions should I look out for?

Thanks

[sjthinkpader]

Due to GPU failures, there are many complete T4x 14 inch display assemblies available for $50 or so. This is the easiest way to fix it.

Unlike most TPs, the T4x 14 inch display bezel does not clip in on the sides, they are held in by the side screws. There are two side tap around the LCD metal frame holding the bezel. These should be replaced but I never do. There are no glue used in the assembly.

[invisibleogre]

Yes, your URL is pretty accurate for replacing CCF.

They have a life of about 3000-5000 hours. Unfortunately most users leave them on or use "screen saver". Nevertheless the backlight was left on which means using up the CCF's limited life.

Using another screen to test it first is the quickest way to make sure it is the CCF going out.

So, this is pretty much my issue, i think.. I was leaving it on while my downloads were going, but left the screensaver up because i didn't think to put the display to rest. I use a port replicator, with an external LCD connected (which i now use as the primary display).

So, my question, as a relative novice when it comes to computer repair, would it be in my best interest to make a go of replacing the display myself? I really want to keep my thinkpad, because I love it and would only give it up if i could afford an X series, which won't be happening anytime soon.. I'm not a total idiot, and I've fixed other things around my home equipped with my tools and the interwebs (xbox 360, simple home repairs), I just don't want to make the problem worse by tinkering, unless i can find a simple step-by-step way to do this... Any advice?