T41 Inverter or lcd cable? problem with lcd

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radiator
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T41 Inverter or lcd cable? problem with lcd

#1 Post by radiator » Sat Jan 31, 2009 2:36 pm

Hi there
I am the owner of T41. When I touch left or right bottom part of ma LCD the bulbs go blind and I barely can sse the windows desktop. I can see what is going on. When i touch the upper part of my lcd and move it up and down nothing bad happens. When I touch near the inwerter and start moving the lid I hear buzzing sounds from the inverter place and then the lcd becomes dark, bust still it is possible to see the desktop. My friend says it the lcd cable but from the above posts it seems to me it is the inverter. What do you think?
And one more thing. I could work without any interference yesterday when moving the lcd lid. It only happens when I move the lid.
thx

poshgeordie
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Re: T41 Inverter or lcd cable? problem with lcd

#2 Post by poshgeordie » Sat Jan 31, 2009 3:30 pm

Hi Radiator and welcome to the forums.

The first thing is to check that you do not have a graphics chip problem by connecting your TP to an external monitor if you have one.

if that's OK then the problems on the TP.

Have a look at the screw removal pdf in my sig for how to strip down the TP; also the IBM hardware manual is listed for stripping down the display.

Areas to check:

1. Remove the keyboard bezel and make sure the tiny lid closing switch at the top left hand side on top of the lcd cable connector is not sticking and making the display switch on and off.
I've often seen the mechanism which fits under the keyboard bezel actually snapped off and resting on the tiny switch and making it switch on and off.
It then needs to be glued back onto the keyboard bezel.

2. If that's OK, make sure the lcd cable at the top left hand side of the motherboard assembly is properly plugged in and held in place with the screw as in my pdf.

3. Onto the display and the lid.
It's not in my pdf, but remove the lcd bezel as in the hardware manual and make sure the inverter part of the lcd cable is plugged in fully into the inverter.
You need to remove the one screw holding the inverter in place and check the multiway connector on the left hand side of the inverter is fully pushed in.

4. Whilst you are looking at the inverter, make sure the connector with the two thicker wires from the lcd is properly connected to the inverter.

5. From what you're describing I don't think it's the main lcd cable connection into the lcd display, but whilst you have the bezel removed remove the 4 (?) screws holding the lcd panel in place and check the lcd cable's properly pushed into the lcd connector.
Be very careful when handling the lcd.

6. If you're still not finding the problem, whilst you have the inverter and lcd panel out of the screen lid, see if you can now find where you need to touch the panel.
WARNING - don't touch the inverter when the TP's switched on since it has very high voltages which will give you a shock. You could try tapping it with a plastic object to see if there's a bad joint on it.

Some ideas to start with...

<EDIT> Corrected the display microswitch position.
Last edited by poshgeordie on Sun Feb 01, 2009 3:49 am, edited 1 time in total.

Rick Aguinaldo
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Re: T41 Inverter or lcd cable? problem with lcd

#3 Post by Rick Aguinaldo » Sat Jan 31, 2009 3:32 pm

The inverter board and the cold cathode fluorescent back light are located at the bottom of the lcd assembly so the poking and response give away the likely culprit. There is a loose connection(s) between your inverter and the CCFL. People have reported broken solder connections at the back light terminals but circuit discontinuities can occur anywhere in between, for example cold solder connections and/or broken circuit traces on the inverter board, etc.

radiator
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Re: T41 Inverter or lcd cable? problem with lcd

#4 Post by radiator » Sat Jan 31, 2009 4:38 pm

ok
thx for you hints
When my monitor is plugged and lcd is dimmed nothing wrong happend on external monitor so GPU should be fine.? right?
After posting my message it turned out tha suddenly strange noises appeared near the inverter. The moment my bulb starts to lit noise appeares and for a moment lcd is normal. After that it comes back to be dimmed. So I decided to see what is inside my lcd. I found out that the inverter gives that strange noises the moment lcd starts to give light. Hence I hesitate whether to buy a new inverter or still continue my research on what is wrong.

Could that noise be produced by the inverter??
ps. all other lcd cables seem to be fine.

by the way thanx foru your warm welcome on forum

poshgeordie
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Re: T41 Inverter or lcd cable? problem with lcd

#5 Post by poshgeordie » Sat Jan 31, 2009 5:54 pm

OK, two choices now.

1. The inverter
The easiest item to replace is the inverter, but before getting one can you send the exact model of T41 - ie the number on the bottom like 2373-4JU.
The correct inverter can be identified, then hopefully where you can buy one, and the approximate price etc.

2. The backlight tube inside the display panel or wiring to it.
To further check this out, use a plastic insulated item like a biro body to move the wires (NOT your fingers), and to gently pull on them.
Does the backlight come on permanently with no noise?
If so it's either a problem with the wire connector joint going into the inverter, or a wire has a bad solder joint onto the backlight inside the display panel.

radiator
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Re: T41 Inverter or lcd cable? problem with lcd

#6 Post by radiator » Sat Jan 31, 2009 7:22 pm

The type of my IBM is 2373-s26
I tried to move the wires light did not appeared. But there is another strange thing about my laptop. When I plugged external power supply for 15 minutes and tried to turn on my black box, there is no problem with my lcd screen. A if there was sth wrong with powering my lcd display, as if there was not enough current supply, but still the problem with moving my lid not solved yet.
I almost forgot, you don't have to search for spare parts as I'm from Poland so the price'd be different. but thx for your involvement

poshgeordie
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Re: T41 Inverter or lcd cable? problem with lcd

#7 Post by poshgeordie » Sun Feb 01, 2009 3:47 am

That would possibly indicate that there's not enough current to operate the inverter, or possibly a component on the motherboard supplying the current.
With too little current the inverter may make a buzzing sound - that is when running on battery; when you plug in the mains adapter and leave it for a while, something is getting 'charged up' so to speak and there's enough current to operate the inverter.

There's another post here, where someone else has a problem with the display going on and off - maybe some help there?

Personally I would buy a new inverter and try that first.

BTW - I made a mistake in one of my other posts - the tiny display switch is on the top LEFT on top of the LCD cable not right as I said (I was confusing it with a T30!). I'll correct for other people.

I'll get an inverter part number from your info.

radiator
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Re: T41 Inverter or lcd cable? problem with lcd

#8 Post by radiator » Sun Feb 01, 2009 3:52 pm

Hi guys!
I have just bought on the auction the inverter. I hope I'll solve my problem. My friend promised me to give one for free but at the end of the month. And I can't stan looking at my black little box standing and acquiring the dust. Keep your fingers crossed let's hope it's going to be the inverter.
I'll let you know about the results.

radiator
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Re: T41 Inverter or lcd cable? problem with lcd

#9 Post by radiator » Tue Feb 03, 2009 10:34 am

I.m writing this post from my IBM t41. I've changed the inverter and for 1 H I can work on my little black box. I'll let you know how my laptop is working. Hope nothing new will come up.
Thx for you support and unvoluable advices.
Thanks onr again

poshgeordie
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Re: T41 Inverter or lcd cable? problem with lcd

#10 Post by poshgeordie » Tue Feb 03, 2009 11:25 am

Great news that!

I hope too that you will now have no further problems.

radiator
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Re: T41 Inverter or lcd cable? problem with lcd

#11 Post by radiator » Tue Feb 03, 2009 2:38 pm

I was just about to get rid of it. But now I think that maybe it is not the time to sell it. I'm dreaming of t60 only with IBM logo. but have no money to buy it besides t41 for my purpose meets my needs !!

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Re: T41 Inverter or lcd cable? problem with lcd

#12 Post by Nameless » Tue Feb 03, 2009 3:25 pm

radiator wrote:I'm dreaming of t60 only with IBM logo. but have no money to buy it besides t41 for my purpose meets my needs !!
That's too bad, 'cuz there's a beautiful T60p for sale in the marketplace forum now. If I didn't already have a T60p myself I'd be sorely tempted to go for it...

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