T23 Backlight Problem, with most usual suspects eliminated

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Musti · #1 Post by **Musti** » Tue Jan 08, 2008 5:11 pm

Hello All

Back to this excellent forum, after working on several computers. As I am in between jobs (P.C. term for "unemployed at the moment"), I needed to revitalize my old T23...

So I decided to fix the backlight problem on my T23. Previously Ray gave some excellent pointers, and Ihave browsed through all posts that had "backlight" or "inverter" in it...I think most suspects have been eliminated.

When the problem started happening 03/2007, there was a sizzling sound around the inverter area and the backlight gradually failed. Resetting the display (via lid or Fn key) brought back the backlight, only for a very short time, with the sizzling beforehand. It was 5 mins, then off. Then it was 30 secs, off. Then 5 secs.

Now here's what has been done.

1. New Inverter ordered. Installed.
2. All cable connections cleaned, reseated. Including the display ribbon, as per Ray instructions

- ribbon cable where it plugs into the motherboard (below the keyboard)
- small rectangular connector in the middle of the inverter board (where the ribbon cable plugs into)
- connector going to the CCFL (at the end of the inverter board)

3. SuperSavage chip tapped. (turn on, take out the keyboard, tap)
4. Gently flexed the screen.
5. Lid switch tests done.
6. Completely strip the machine, including the LCD (yay! it is a Samsung)

And here's what happens.

1. Turn on T23.
2. I briefly (1sec) see the IBM logo, then backlight goes away. As I didn't install the backup battery, comp goes to BIOS (no OS loaded yet).
3. Hit Fn-F3 for display sleep. Sleeps.
4. Hit any key, wakes, shows the BIOS screen for one sec, then goes away.

In other words, I can only have backlight for one second.

Now with your permission, here are the issues over which I have been consuming ridiculous amounts of caffeine for two nights straight...

1. If the replacement (direct from IBM) inverter is faulty, there shouldn't be any backlight whatsoever? The symptoms are the same with the old and the new inverters.

2. I can turn on-off the ThinkLight, which is also fed by the display cable, which leads me believe the ribbon cable is OK. Can it be partly damaged?

3. If the board is faulty, can I still have a one second backlight?

Any other thoughts?

Oh, and a healthy, happy (and belated) New Year to fellow ThinkPadders.

MintyMadness · #2 Post by **MintyMadness** » Tue Jan 08, 2008 5:21 pm

It sounds like one of your bulbs inside the LCD is burned or shorting out. This happend on a Compaq LCD (19" - desktop) that I had. it has two bulbs, and the bottom bulb was burned. It would turn on and show a screen for all of 1-2 seconds and then go blank.

Here is a question,

When the LCD flickers off, if you hold a flashlight up to the screen (backside preferably) can you make out anything from the bios (or whatever else you may have on the display) For me it was the start button.

In any event, I Was able to replace both bulbs (may as well, when you are in there already..) and the screen now works flawlessly

-Jeremy

Musti · #3 Post by **Musti** » Tue Jan 08, 2008 5:35 pm

Hey Jeremy
Thanks and a quick answer: I can see (via flashlight) that there's video. So, yes.

Bulbs, eh? hmmm...will be a pain to find them here in Bodrum...

MintyMadness · #4 Post by **MintyMadness** » Tue Jan 08, 2008 5:52 pm

I have seen this link posted here before in another thread. This is the site I also get my bulbs from.

Link!

Keep in mind that replacing bulbs in a laptop LCD can be a grueling task, not for the faint of heart. I would consider myself fairly well rounded now that I have done it on a lot of varying sizes of LCDs, but I still cringe with laptop LCDs. Solder points need to be VERY clean... Dekstop LCDs have more room so to speak, in which to work with as well.

Only undertake this task if you are up for it! otherwise there are members here who will work out a deal with you probably on backlight replacement.

Hope it helped!

-Jeremy

EDIT: Also if you do this, don't break the bulb around your face!! Wear a facemask in any case, I always do. The gasses inside this CCFL's can be poisenous from what I heard, so I don't take any chances...
Also, your bulbs may be ok, check to see if maybe a solder-point has come loose or broken, this would also cause a short.

jamerslong · #5 Post by **jamerslong** » Tue Jan 08, 2008 6:46 pm

i would agree with madness and check ALL solder points, I personally don't find Disassembling an LCD to replace a backlight to be that bad of a chore, but it isn't easy either.

and easy way to test would be to find another display and plug it up to see if it works, if it does not then the problem lies within the Laptop, it it does work then the problem lies withing the LCD area. but try switching the inverters first.

Also as madness said, The bulbs have poison in them, to include Mercury http://en.wikipedia.org/wiki/Mercury_poisoning

I would also suggest wearing surgical gloves when handling the bulbs as
A: oil from your body can harm the bulb
B: mercury can be absorbed through the skin
a long sleeve shirt would be a good idea as well.

#6 Post by **RealBlackStuff** » Tue Jan 08, 2008 6:47 pm

jamiphar offers to replace those backlight tubes in the Marketplace forum.
http://forum.thinkpads.com/viewtopic.php?t=48458

Website · #7 Post by **tfflivemb2** » Tue Jan 08, 2008 7:50 pm

Pay VERY close attention to the wires that connect the inverter to the CCFL. I had a T30 that had these same symptoms, and it turned out that there was a slight slit in one of the cables that was shorting it out.

#8 Post by **rkawakami** » Tue Jan 08, 2008 7:59 pm

"Sizzling" from the inverter is very familiar...

http://forum.thinkpads.com/viewtopic.ph ... 603#333603

It seems to be that there's an automatic shutdown feature in the T2x inverter boards. With no load (backlight disconnected) the inverter will make some noise and MAY self-destruct. That you are getting some light from the CCFL and then nothing tells me that the problem is with the backlight or as Steve suggests, the wiring. If possible, substitute another LCD panel with the same inverter(s) and see if that helps.

edit: Corrected "no load" condition to explicitly mean that no backlight is connected to the output of the inverter.

Musti · #9 Post by **Musti** » Tue Jan 08, 2008 9:06 pm

Thank you all...although the problem remains, just the amount of response I get here is amazing...

I tried with both inverters again, checking for broken cabling. None found, the cables are good.

Display sleep, wake, 1-2 second backlight, the sizzling sound, then poff, gone. Repeat.

Interestingly, the sizzling sometimes comes from the left side of the inverter board, sometimes right. Or is it the panel's bottom edge that sizzles? Oh well.

4 AM local time...with itchy eyes and mouth sour from coffee & cigarettes (I know, I know), I'm starting to think I have a bad LCD...dead backlight.

Consensus?

Thank you, folks.

Website · #10 Post by **tfflivemb2** » Tue Jan 08, 2008 9:25 pm

Dumb question...are you sure that the cable is plugged in correctly to the inverter? It will unfortunately go in backwards and create a sizzling/popping noise.

Robbyrobot · #11 Post by **Robbyrobot** » Wed Jan 09, 2008 10:56 am

B: mercury can be absorbed through the skin

It can't and the danger is highly exaggerated. Incidentally, I'm a Ph.D. organic chemist and have worked in toxicology.

Mercury itself is harmless, you can swallow it and it'll pass through the intestine without any particular effect. Mercury compounds, if ingested over a period of time, can poison you - but we're not talking about replacing one or two CCFLs here, even if all the mercury in them were present as a water or fat soluble compound, which it isn't.

Mercury vapor from finely divided mercury is toxic, which is why people in the lab used to put down sulfur to react with the mercury anytime there was a spill.

My advice: work carefully, try not to break the tubes, wear unpowdered gloves to prevent skin oils from contaminating the tubes or reflectors - and relax. You're not going to die or go insane if you break a tube.

jamerslong · #12 Post by **jamerslong** » Wed Jan 09, 2008 11:15 am

The amount of mercury in 2 CCFL's wont hurt you enough to make you extreamly sick or die, but it might irritate you. the only reason I show so much caution towards mercury is because I don't know what kind of mercury is inside these tubes, but it is a vapor/gas form of some sort and not the kind you see in a thermostat for
your air conditioner.

I woud rather be over cautious then ignorant to the things Ive heard.

MintyMadness · #13 Post by **MintyMadness** » Wed Jan 09, 2008 11:38 am

jamerslong wrote:The amount of mercury in 2 CCFL's wont hurt you enough to make you extreamly sick or die, but it might irritate you. the only reason I show so much caution towards mercury is because I don't know what kind of mercury is inside these tubes, but it is a vapor/gas form of some sort and not the kind you see in a thermostat for
your air conditioner.

I woud rather be over cautious then ignorant to the things Ive heard.

Agreed.

I don't want to be the one that finds out that gasses from two CCFL tubes actually can make you cough blood, or whatever it may be..

"better safe than sorry."

-Jeremy

Robbyrobot · #14 Post by **Robbyrobot** » Wed Jan 09, 2008 12:21 pm

I don't know what kind of mercury is inside these tubes, but it is a vapor/gas form of some sort and not the kind you see in a thermostat for your air conditioner.

It's present as the metal, and ionizes when high voltage is applied. Actually, there's not enough there to see except as a gray haze on the walls of the tube.

I agree with your "better safe than sorry" attitude, and also wouldn't lick out broken tubes just for fun. But dangers can be exaggerated and as I noted, you won't suffer any harm from merely working on such tubes any more than you do when you work on a fluorescent light (which is just a larger version of the CCFL).

Musti · #15 Post by **Musti** » Wed Jan 09, 2008 2:19 pm

tfflivemb2 wrote:Dumb question...are you sure that the cable is plugged in correctly to the inverter? It will unfortunately go in backwards and create a sizzling/popping noise.

It occured to me as well. Most of the connectors have tiny grooves, that make them attach in one way.

Oh, for the ensuing health discussion, I am not going to open up the screen myself. Will be on the lookout for a donor machine around here, checking the used PC lots and such.

Musti · #16 Post by **Musti** » Thu Jan 10, 2008 11:23 pm

I think I have found a replacement LCD. Will let you guys know...

beeblebrox · #17 Post by **beeblebrox** » Fri Jan 11, 2008 9:51 am

rkawakami wrote:"Sizzling" from the inverter is very familiar...

http://forum.thinkpads.com/viewtopic.ph ... 603#333603

It seems to be that there's an automatic shutdown feature in the T2x inverter boards. With no load (backlight disconnected) the inverter will make some noise and MAY self-destruct. That you are getting some light from the CCFL and then nothing tells me that the problem is with the backlight or as Steve suggests, the wiring. If possible, substitute another LCD panel with the same inverter(s) and see if that helps.

edit: Corrected "no load" condition to explicitly mean that no backlight is connected to the output of the inverter.

The CCFL is dead. The emitter in the end is not able to emit electrons anymore , either if the radioactive probe is exploited to induce free electrons or the emitter in the CCFL itself is either cut or shortcut due to heat retransfer at the wires. This happens at the end of lifetime of the CCFL. The inverter board increases voltage to induce the free electrons to start ionize the mercury krypton gas, but it can't. The sizzling sound comes from the surface piezo crystal that is used to create the high voltage. Finally with around 1300V the CCFL happens to discharge and light up. But the current is way too high for the inverter and it shuts down for safety. Inverters drive usually 5-6mA and then shut down. If the CCFL is dead, the inverters does NOT die. Modern inverters have a lot of safety. However the T23 is from the year 2001, so I am not sure about these old ones. It could also be that the inverter itself is not able to maintain the 5mA current anymore and after discharge of the CCFL the voltage collapses due to a weak inverter. Systematically eliminate the source of problem, methinks, is the best way.

I have replaced a few CCFLs already. No big deal.
Next week I have two T23 from friends and family that need a new bulb (red teint and yellowish dim light).
CCFLs cost only $20. Replacement is 20 minutes. For those who know how to do it. I suggest to go for longlife 7400Kelvin (neutral white) CCFLs that emit 40.000cd/m2 which will propel your T23 to near VibrantView brightness!

Musti · #18 Post by **Musti** » Sat Jan 12, 2008 4:22 pm

Musti wrote:I think I have found a replacement LCD. Will let you guys know...

Sadly, the replacement LCD was just that: so good to be true, for 100 YTL, roughly USD 90. It was for 13.3...Though I can keep the inverter, I'd be needing a new ribbon cable, new top chassis, etc...so I will go with the CCFL route.

Now I am in the process of obtaining a CCFL from Istanbul (so God help me hehe). One question for you folks: how safe will it be to have it shipped from the States to Turkey? Even if it is securely packed and all, I know these are fragile tubes...is it too risky (for DOA) for overseas transport? I even wonder if it will be shipped properly (read: without breakage) from Istanbul to where I live now (one night's cargo).

Brad · #19 Post by **Brad** » Sat Jan 12, 2008 4:36 pm

Much great information here.

Thanks for all the replies. I don't have a problem (yet?) but if I did I know there is a lot of great information available.

Thanks again,

Brad

#20 Post by **Harryc** » Sat Jan 12, 2008 4:49 pm

I just ordered a CCFL from LCDPART.com and it arrived in a very sturdy long box. I don't think a trip to Turkey would hurt it ... and they do ship international.

Musti · #21 Post by **Musti** » Mon Jan 14, 2008 5:01 pm

Thank you all for your responses. You guys are just great.

I think I've fixed the problem.
Bit the bullet and tore the machine apart after finding a LCD CCFL from Istanbul (haven't ordered yet). To my surprise one of the cables were broken at just the connection to the CCFL tube (came loose from the silicone cap). I could only see this after I'd taken the CCFL out completely. I fixed it, rerouted the cables, and voila...it is working now. I must have done this in haste as the light dispersion at the bottom of the LCD is not uniform, but I am not going back there...I can live with this.

Now in the lookout for a hinge cover, as my friend who previously attempted repair broke the original.

One word of warning for future repairers who happen to read this thread: the hinge cover is an essential piece, it binds together the top case, the middle metal casing that also attaches to the hinges, and the bottom casing. Looking from top, the right-most screw does this. The screw casing/tube is broken in mine (argh, friend!!!) so the screw does not hold, thus I cannot open/close the lid as this puts extra strain on the inside metal and also the right hinge is not covered properly...

The hinge cover comes in "System Misc Parts", P/N: 12P4229, a collection of bits and pieces...essential piece let me tell you

Again, thanks all.

#22 Post by **Harryc** » Mon Jan 14, 2008 5:27 pm

Post a thread in the Marketplace forum asking for the hinge cover. A member here might have one.

#23 Post by **RealBlackStuff** » Mon Jan 14, 2008 5:57 pm

If all else fails, try and apply some 'Gorilla' glue http://www.gorillaglue.com/
or whatever equivalent is available in Turkey.
Another strong glue is Cyanolit which is probably available there.

Robbyrobot · #24 Post by **Robbyrobot** » Tue Jan 15, 2008 2:40 am

The screw casing/tube is broken in mine (argh, friend!!!) so the screw does not hold, thus I cannot open/close the lid as this puts extra strain on the inside metal and also the right hinge is not covered properly...

I noticed the same thing in the A2x series and repaired the site with two-component epoxy, taking the brass nuts/casings from a broken base I had. Maybe you can do the same.

Musti · #25 Post by **Musti** » Fri Jan 18, 2008 7:36 pm

Robbyrobot wrote:I noticed the same thing in the A2x series and repaired the site with two-component epoxy, taking the brass nuts/casings from a broken base I had. Maybe you can do the same.

If only I had the broken pieces (I noticed only one screw holds the hinge cover, the others' housings are borked). This puts extra strain on hinges when hinge cover plastic is not secured.

I checked the Marketplace and bought a hinge cover and an LCD to be shipped here. Never hurts to have a spare LCD, especially when they are hard to find and mine is iffy.

Thank you all for all the responses, it was a fun learning experience.

lucky_ufo · #26 Post by **lucky_ufo** » Tue Feb 19, 2008 9:37 pm

Dear All,

I need help. I sent a T23 to my buddy to Hungary. He was using it for few months. Once while he was using it the laptop froze so he turned it off. When he turned it back on a window popped up and he automatically pressed enter without paying attention to it. Since that moment on the backlight is off. I am just wondering if there is any way that he might turned off the backlight by pressing the enter button. If yes can the backlight turned back on again?
Thank you kindly for your advice in advance.

Lucky
Toronto

twiceferrel · #27 Post by **twiceferrel** » Tue Apr 08, 2008 4:04 am

fn + home turns the backlight up and fn + end turns the blacklight down. Also, fn + f7 cycles through different inputs (monitor, external something pluged in, something else), I think three (so you might have to press it a couple of times.) fn + f3 also turns off the backlight, I think.

You can go to lenovo's webiste here and download the maintainance manual. I think all that info is in there. If not there are other manuals for the T23:

http://www-307.ibm.com/pc/support/site. ... UYM3F.html

T23 Backlight Problem, with most usual suspects eliminated

T23 Backlight Problem, with most usual suspects eliminated

back light turned off?

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