T41 Screen problem

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mamp · #1 Post by **mamp** » Wed Oct 08, 2008 1:20 pm

I have a 4 years old Thinkpad T41, 14.1" laptop.

Suddenly, this morning, when I turned it on, the screen remained blank!
Since that time, I have a have a dimmed screen, meaning that the screen displays the items, colours, etc, but it is very faint! ( I can hardly see the items on the screen, only if light reflects on the screen )

The funny thing is that when I log into Windows XP, nothing, and I mean nothing, appears on the screen!
However, when I boot, or log into linux, the screen displayes the items, but very faint, as I described above.

Apart from that, the whole computer is running normally, hard disk, processor, etc and also the external monitor port is working normally as well.

Is this an inverter failure, a blacklight lamp failure, or an an entire LCD Screen failure??

How should I proceed from now on?

Thanks in advance,

Marios.

#2 Post by **jdhurst** » Wed Oct 08, 2008 2:47 pm

Probably the easiest thing to try is a whole new lid. You can sometimes get them on eBay or here in the forum fairly economically. ... JDH

Pingwin Wielki · #3 Post by **Pingwin Wielki** » Thu Oct 09, 2008 2:06 am

Well, when the backlight lamp gets old, you can notice an excess of a red colour on the screen... It is due to fluorescent lamp spectrum characteristics. Therefore backlight problems are easy to notice: you can just compare your screen with another LCD screen and if you can notice it is "reddish", that means that the backlight lamp will need to be replaced soon.

Your problem was sudden and unexpected. That's more alike to inverter malfunction. It seems to have no enough power to turn on the backlight lamp.

Is your ThinkPad under warranty? This problem should be repaired easily, but let professionals do it, if possible

Oh, one more thing... what about the status LEDs on the bottom edge of the screen frame? Are they turned off all the time? (status leds are integrated with inverter, so if all leds are gone, it means that inverter gets no power from the motherboard) Otherwise it may be the inverter high-voltage transformer circuit failure.

If I had such problem, I would try the cabling of inverter: take off screen front frame, check if both cables (one to the fluorescent lamp, the other to the motherboard) are attached firmly. If this doesn't help, you may need to replace the inverter.

And one more thing... Don't forget to visit this thread (F7 fuse issue?):

http://forum.thinkpads.com/viewtopic.ph ... t=fuse+map

mamp · #4 Post by **mamp** » Thu Oct 09, 2008 4:06 am

Thank you very much for your answers guys!

Well, the green indicators of the screen are still working properly.
I didn't experience any "reddish" effects or anything like that the days before. It all happened suddenly!
Is this an inverter issue after all, even if the green indicators are on?

Unfortunately, the warranty has expired...

What about the fuse issue? How am i supposed to reach and replace that issue? By accessing the mainboard.

Many thanks!

Marios.

ajkula66 · #5 Post by **ajkula66** » Thu Oct 09, 2008 4:43 am

Does the machine display withan external monitor?

mamp · #6 Post by **mamp** » Thu Oct 09, 2008 4:55 am

Yes, it works normally and perfectly with an external monitor!

sparta.rising · #7 Post by **sparta.rising** » Thu Oct 09, 2008 8:44 am

This seems like one of the most asked questions...

Four things could be wrong
1) Bad CCFL tube
2) Bad inverter
3) Bad LCD cable
4) Bad fuse on the motherboard

1) In my somewhat limited experience, this is the most common cause of a "dim screen". Usually the wire will become disconnected from the tube or the CCFL tube itself will crack or "pop". Its relatively easy (emphasis on relatively) to see if this is the problem by removing the tube from the LCD panel and seeing if the cable has disconnected or if the tube is broken. If the cable has disconnected often the rubber and plastic around it will be charred/melted. This is because the current will try and jump the gap. This may result in your LCD momentarily turning on and then shutting off. You can test the backlight assembly without removing it from the LCD panel by removing the LCD panel and plugging the wire harness into the inverter of a known working LCD assembly. If the tube comes on, it is one of the other listed problems.

2) Bad inverter. Even if the LED indicator lights are functioning, the inverter may still be broken. The easiest way to test if this is the problem is by replacing the inverter with a working one. Either buy a new one or temporarily borrow one from a known working LCD assembly.

3) Even if the LCD is displaying a picture, the LCD cable may still be at fault. This is most common on older machines where the cable has worn out. The backlight power is often carried on the wire the farthest to the edge of the cable. The wire fails from mechanical wear - as the monitor is open and closed, the cable is bent, the wire inside the cable is metal, and like all metal, it will eventually wear and fail. Like the inverter, the best way to test this is to test your cable with a known working LCD assembly and motherboard or to buy a replacement part.

4) Before you begin testing the fuses, if you have another machine available, remove the entire LCD assembly and test it on that machine to determine if the base is at fault. Fuses on the motherboard can be checked with a multimeter. Diagrams of the location of the fuses can be found by searching the appropriate forum. You can find them yourself as they are labeled "FXX" (where XX are numbers) on the motherboard. Set your multimeter to a high Ohm setting. Take your multimeter probes and place them across the fuse. If the multimeter reads zero 0, the fuse is good (the fuse is showing zero resistance, ie a short, which means the fuse is not broken). If the multimeter reads another number, usually very high, the fuse is bad (the fuse is showing infinite resistance, ie a disconnect, which means the fuse is broken). You will need to find an appropriate replacement fuse and solder it to the board.

mamp · #8 Post by **mamp** » Thu Oct 09, 2008 9:24 am

Thank you very much for your answers!

You are all very helpful indeed!

Well, I just started with the "easy" part. I ordered a new inverter, and I will replace the old one with that.
I hope that it will work... otherwise... I will try the problem with the fuses.
As a last hope, I am thinking of buying a
whole lcd screen, with the plastics, cables, antennas, etc, and to replace my old one with that.
I hope that the inverter replacement solution will be successful one!

In any case, I 'll let you know about it. If you can give me more guidance or advice relating to my problem, I 'll be glad to receive it!

Many thanks again!

Marios.

fozzy40 · #9 Post by **fozzy40** » Thu Oct 09, 2008 11:50 pm

Mamp, please let us know how this works out. I have a T43 and developed almost the same problem. My laptop was working perfectly fine and then all of a sudden the screen will become dim as you said. If I restart the computer though the screen is working again.

Keep us posted!

sparta.rising · #10 Post by **sparta.rising** » Fri Oct 10, 2008 12:19 am

Lets make sure we understand "dim". By dim, there is no light coming out of the LCD panel, without direct light you can't see anything. If its just not as bright as usual, check your power settings.

If its going dark randomly, then its a backlight problem, not inverter. If its going dim when you move the screen, then your LCD cable is probably just loose where it connects to the panel.

fozzy40 · #11 Post by **fozzy40** » Fri Oct 10, 2008 1:49 am

The screen is going dark randomly more frequently now. From what everyone is saying, it sounds like a backlight problem now. What can/should I do?

T41 Screen problem

T41 Screen problem

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