How long before significant dimming of CCFL backlight?

[archer6]

I have a question regarding the average (if there is such a thing) life of a CCFL backlit display, before noticeable or significant dimming occurs.

Since I have several ThinkPads I've not used just one for long enough to notice much dimming of the display. However that said, I do have one exception and that is my T60 equipped with a 4:3 SXGA+ IPS display. I purchased it new in Feb of 2006, and now compared to my other non-IPS, CCFL backlit ThinkPads, it's about 40% dimmer.

I would estimate I have about 4,000 hours on it. The question that comes to mind is just how long does CCFL lighting go before it dims noticeably? Does it make a difference that it's behind an IPS vs Non-IPS panel? I've done a lot of searching and found quite a bit of info about CCFL, and that it _does_ dim as it ages, but no estimates or comments on how long it takes. I look forward to your take on this subject.

Cheers...

[GomJabbar]

I had a backlight dim and then fail on a 2 year old T42 XGA display, and on another 3 year old T42 SXGA+ display. My wife has been using her T42 XGA for about 3 years without a problem. Perhaps travel, vibration, or running it from power supplied by a 100KW generator shortens the CCFL life.

I took the backlight out of the first T42 and discovered that it is about the diameter of round toothpick and 11" long. It could be that backlights for other displays have a larger diameter. I would think that a larger diameter backlight may last longer - but this is just speculation.

http://forum.thinkpads.com/viewtopic.php?f=18&t=38664

[archer6]

Yikes....

What a story!
What a thread !
What a basket of snakes......me..... replace or repair it myself ? Noooooooo

Thanks for the slap of reality, I think...

Cheers...

[Tõnis]

I wonder if the level of brightness one normally uses has anything to do with the backlight's longevity. Does leaving it on full brightness versus dimmed make any difference in how long it will last?

[archer6]

Keep those replies coming people, I'm really eager to hear your experience. Tell us your story about how long your display's backlight lasted before becoming noticeably dim. Was yours a regular TN display or IPS / Flexview?

Thanks

[rkawakami]

Perhaps a related data point for LCD brightness change over time...

My favorite SXGA+ T23 arrived in my hands in Oct. 2006 (2647-HNU with a build date of 2002/02). It came with a pinkish hue on power up which goes away at full brightness (what I've always run it on) in about 20-30 seconds. Despite the common wisdom that such a tint is a sign that the CCFL is on its way out, that screen has continued to work almost daily for the past 2.5 years without any apparent change in intensity. In the last month or so it has seen limited use since it's still in the laptop bag that I used for work but I've just plugged it in again and it seems to be as bright as when I first started using it. It could be that it was significantly brighter in its younger days and that after a couple of years, reached a plateau.

[archer6]

Despite the common wisdom that such a tint is a sign that the CCFL is on its way out, that screen has continued to work almost daily for the past 2.5 years without any apparent change in intensity.

Out of all my ThinkPads, just this one T60 with it's 15" IPS Flexview display is the dim one. Very dim, when side by side with my CCFL Z60m 15.4" which I purchased new in the same month of 2006. The brightness of the Z60m seems to be as good as the day it was new, or very close to that.

It is because it's an IPS display ?

What is your personal viewpoint on CCFL vs LED? Considering all of your experience with displays I would enjoy hearing your take on the subject.

Cheers...

[rkawakami]

I actually haven't seen any LED panels in person yet so I can't comment on that. Have one working A31p and it seems a little bit dimmer than several of my XGA T23s. My newest system (in both build date and ownership) is an X41T with the FFS panel. It doesn't seem to be much brighter than any of my X2 systems. The only "new" Thinkpad that I've ever used is an R61. That display was a little bit brighter out of the box than most of the T23 (XGA and SXGA+) panels that have been through my hands but that's probably not a fair comparison since there's about a 5 year age difference. About the only system that I can say for sure has dimmed over the time that I've own it is a 600E. It's the first Thinkpad that I bought 7 years ago (used) and has probably decreased its light output by about 1/2 the amount provided by the sliding brightness control.

[ajkula66]

Given the technology (quite old but never the less brialliant) behind the IPS I'm going to say that these LCDs do strain the CCFL more. My personal experience also seems to prove that.

Running the screen at full brightness (which is what I always do) has to have some (negative) effect on the life of the bulb itself.

For some reason, I've seen quite a few SXGA+ panels on T60 machines that have lost their brightness quicker than expected. My assumption is that it was just a bad batch of CCFLs...

Now, on how to go about it, here's where I stand:

a) If the machine is covered under warranty, have Lenovo take care of it.

b) If it's not, the LCDs that come from James (jamiphar) with a replaced backlight look better than new, and I'm being perfectly serious about this. The only issue here is that any imperfections that the screen itself might have (pressure mark, dark spots, hair...) will become more evident (and annoying) with a new CCFL.

Hope this helps.

[archer6]

<snip>Running the screen at full brightness (which is what I always do) has to have some (negative) effect on the life of the bulb itself. For some reason, I've seen quite a few SXGA+ panels on T60 machines that have lost their brightness quicker than expected. My assumption is that it was just a bad batch of CCFLs...

the LCDs that come from James (jamiphar) with a replaced backlight look better than new, and I'm being perfectly serious about this. The only issue here is that any imperfections that the screen itself might have (pressure mark, dark spots, hair...) will become more evident (and annoying) with a new CCFL.

I also have run mine at full brightness, and I do agree with you, it could be nothing more than a bad batch of CCFL's. Since I am not under warranty, would you be so kind as to provide further explanation on James, as I'm not quite sure what you meant. Does he repair them? Since you provided "jamiphar" is that his user id here? If not how would I contact him. Unfortunately I allowed my warranty to elapse not realizing they would cover something like this.

Your help is greatly appreciated. Since this is my number one most favorite ThinkPad of them all, I would like to prolong it's useful lifespan. Other than the dim display it's a 9.5 in terms of condition and performance.

Cheers...

[archer6]

The links I ferreted out below support that statement.

Wow... Thanks for your efforts to find this.

Wow... I hit the wrong button.. Edit instead of quote... now I blew out all your good work...Sheesh

Bad Mod <---------------

I sure made a mess out of this one...Yikes!
I even mistakenly deleted your post.... Sorry!
I keep digging this hole deeper.....

[GomJabbar]

Wouldn't you know it, I just closed those tabs before coming back to this thread.

Running the screen at full brightness (which is what I always do) has to have some (negative) effect on the life of the bulb itself.

The links below support the above statement.
http://www.maxim-ic.com/appnotes.cfm/an_pk/3528

http://www2.electronicproducts.com/Sele ... -html.aspx

http://www.sanken-ele.co.jp/en/prod/sem ... fl_07e.pdf

http://www.mpi.ch/files/File/Integrated ... /CCFL_.pdf

http://www.holtek.com.tw/english/tech/a ... a0102e.pdf

EDIT: Added quote and text that was in my original post.

[ajkula66]

@archer6:

You can familiarize yourself with James' work in this thread:

http://forum.thinkpads.com/viewtopic.php?f=11&t=48458

He has replaced several backlights for me on different IPS-equipped ThinkPads and these LCDs were so wonderfully bright it wasn't even funny. Mind you, I've owned new IPS units, as well as ones with "fresh replacements" from IBM done on my watch, but LCDs returning from James have been the best one I've ever seen.

Hope this helps.

[jdhurst]

I used my T41 for five years daily and replaced the screen (including backlight) once. It didn't seem to dim that much. I have been using my T61 as a daily driver since September 1 last year and it has not noticeably dimmed.

One thing I read a while back and adhere to is that my power saver for both my T61 and my IBM Desktop with LCD monitor is to turn the screen off entirely. I have not used a screen saver for many years. When the monitor goes off, the backlight turns off as well. That seems to help. I purchased the LCD monitor for my desktop about 5 years ago and it has not dimmed at all (although it is not lit up as much either)

In terms of replacement, it was quite easy to get a replacement lid (screen, backlight, antenna wires, hinges et al) from eBay at a low cost, and fairly easy to replace it. I have not removed the lid from my T61 but it doesn't look to be difficult. I would not try to replace the backlight on my own and in any event, the complete lid was a bargain.
... JDH

[TTY]

...how long does CCFL lighting go before it dims noticeably?

The product specification for a 15" BOE Hydis UXGA FFS notebook panel (HV150UX1-101) specifies lamp life to 12,000 h minimum and 15,000 h typical. Lamp life is defined as the time it takes until backlight brightness has reached 50% of the initial value.

An Engineering Specification for a 15" IDTech UXGA notebook panel (N150U3-L06) mentions a lamp life of 10,000 h. I guess that it's an IPS panel, as horizontal viewing angles are specified as 85° for left and 85° for right.

I don't have specs for 15" SXGA+ panels but suppose that lamp life for those will be similar to lamp life of UXGA panels.

[rkawakami]

Reviving an old thread with new information....

Well, the day has apparently arrived . My daily driver T23 turned on today with a much dimmer display. It is noticeably grayer than the Dell Latitude that sits on my desk here at work; they were the same yesterday. The screen flashes every now and then to the brightness that it had before. I don't believe that it's the inverter or the LCD cable that's causing the problem. Over the last few months the lower corners have developed dark shadows. So after about 3.25 years of daily use, figuring in the couple of months that I was between jobs, there's my data point on how long it took for a pinkish display to become significantly dimmer. I would guess that I've put on at least 3,000 hours since getting the system back in late '06 (3 years x 200 working days per year x 5 hours per day; conservative estimate).

So I guess it's now time to either do a lid transplant, CCFL replacement or simply move the hard drive to another SXGA+ wireless T23.

edit: Three hours after I posted this, the backlight finally went out. No real warning other than the occasional flash that I've been seeing this afternoon; it just simply turned off.

[rkawakami]

Follow-up:

Well, I took the path of least resistance. I simply moved all of the hardware (HD, battery, memory, Ultrabay, wireless card, Ultraport interposer) into a 2647-9NU I keep at work. It too has a slightly reddish screen at power up but the brightness is about 25% better than the HNU that just died. The keyboard is much nicer too (no greasy fingerprints or cat hair!). This was a dead parts/repair only system off of eBay almost exactly two years ago today (5/3/08). Had a fried motherboard so my notes said I popped in a spare one and replaced the broken keyboard bezel.

I'm starting the "how long will a reddish tint backlight last?" timer on this one . If all goes well, I guess this will be my "new" system.

note: Seagate drive 5PL4EPYY has 1200 POH as of today. Estimating around 50 hours on the 9NU running various PC Doctor, memtest86+ and SeaTools diagnostics since 5/08.

[hts]

I have used a T21 virtually everyday 8+ hours a day since 2001. After about 7 years the CCFL dimmed to the point where it needed replacement. I bought a replacement CCFL for less than $10. I chickened out on the installation and got the shop that sold the CCFL to do the labor for @ $60. The screen has been brighter than ever.