T41 Dim Display

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fuzzypup
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T41 Dim Display

#1 Post by fuzzypup » Tue Mar 01, 2011 8:56 pm

I have a T41 2373-8RU that has developed a dim display. I can faintly see the IBM logo when booting. I replaced the inverter on that display but no change - still dim. I then installed a different display that worked fine on a T42 and get the same dim result on the T41. Pressing Fn and Home have no effect.

Any suggestions would be appreciated.

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Re: T41 Dim Display

#2 Post by fuzzypup » Tue Mar 01, 2011 10:08 pm

I have attached an external monitor and the display is fine on the external and dim on the known good LCD I have attached to the T41. Any setting I am missing here?

ajkula66
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Re: T41 Dim Display

#3 Post by ajkula66 » Tue Mar 01, 2011 10:10 pm

I'm going to throw a guess that would go along the lines of a blown fuse on the motherboard.

Good luck.
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Re: T41 Dim Display

#4 Post by poshgeordie » Wed Mar 02, 2011 2:41 am

ajkula66 wrote:I'm going to throw a guess that would go along the lines of a blown fuse on the motherboard.

Good luck.
+1

Download the How To's & Info doc in my sig, and then T4x Fuses doc.

The fuses to check are F3, F7, F8.

To do this you need a multimeter.
First disconnect the AC Adapter and Battery.
Check the fuses for continuity using the multimeter.

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Re: T41 Dim Display

#5 Post by Geoffzie » Mon Dec 26, 2011 9:21 am

I know this is an older thread ... but I'm having the same problem with an R51 with 14.1" screen. I've also searched the web ... and apparently, there are many others having this same problem on similar models.

I purchased 2 Thinkpad R51's from eBay ... 1 is a 15" and the other a 14.1". The seller said the 14.1" had a dim screen ... I just assumed it was the inverter.

Here's what I've tried ... 3 different inverters (one known good tested one) ... 2 LCD's (one known good one) ... 2 ribbon cables ... downloaded the T4xFuses.pdf diagram of T41 MB and checked ALL fuses including F3, F7, and F8, all checked OK ... set LCD to "bright" in Bios ... checked the lid switch ... updated the Bios to latest version ... I even tried swapping a good 15" MB (another one I had - not the one I purchased from eBay) ... and the LCD came on initially ... then went dim?!

BTW, the R51 motherboard looks VERY similar to the T41 in the diagrams I downloaded.

The Thinkpad works perfectly ... except for this ... using an external monitor, I've loaded Windows and checked everything, charging, running on battery, all components, audio, video, ethernet, wireless, ram, hard drive, keyboard ... EVERYTHING works fine ... except LCD!

Any of you Thinkpad Guru's out there have any ideas? I'm thinking that it's got to be in the motherboard ... if not the fuses, then some motherboard component failure relating to the inverter. What was also strange was that when I installed the 15" R51 motherboard ... it worked for a few seconds ... then went dim. Could switching parts on these things cause something to "blow" on the motherboard?

ANY ideas or thoughts would be appreciated.

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Re: T41 Dim Display

#6 Post by poshgeordie » Mon Dec 26, 2011 9:46 am

Hi Geoff and welcome to the forums.

<Amended Post>
Just read that you have an R51 which may mean you have an Intel Graphics chip- only refer to the fuses and LCD Cable parts!

Have you actually checked the fuse(s) on the board / are you able to? Fuses doc link is here.

Regarding swapping screen assemblies, it's vital to match the right LCD Cable with the right Screen panel, and having the wrong one can cause the board fuses to blow. If you search the forums there's lots of information about what cable goes with each screen, and no doubt someone else will come along with the relevant part numbers too.

There's also an outside possibility that the Graphics Chip needs reballing. The ATI GPU has two separate video outputs- digital to the internal screen and analogue to the external VGA Connector. Depending on where you live this can be straightforward to repair (UK and Europe), or to obtain refurb'd boards USA Board Room.

Also could you update your profile to show which country are you from. This will help us point you to people who might be able to help you with repairs if needed.

<Amended to add Intel GPU section>

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Re: T41 Dim Display

#7 Post by Geoffzie » Mon Dec 26, 2011 1:48 pm

I have the R51-15" motherboard in it right now with the ATI Video ... but the original R51-14' motherboard with Intel Video was dim too.

Yes, I've checked all the fuses, but I'm going to check them again just to make sure ... and check the voltage AT the fuses. One of the other threads here narrowed it down to the F7 fuse, I believe.

You say there are two video outputs for the video ... but wouldn't they both use the same ATI or Intel video GPU?

If all else fails, I could just buy another tested 14" R51 motherboard off eBay ... I've had pretty good experience doing that, when I buy from a reputable seller with good feedback and a warranty ... but I'd like to try and fix this one.

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Re: T41 Dim Display

#8 Post by poshgeordie » Mon Dec 26, 2011 1:56 pm

Geoffzie wrote:You say there are two video outputs for the video ... but wouldn't they both use the same ATI or Intel video GPU?
Yes this is correct. There are around 700 tiny solder balls on the GPU chips, and completely separate video outputs - I've seen one output fail on a number of these models and it'was some unsoldered solder balls.

Also have a good look at the internal video connector on the motherboard too to make sure there's not a damaged pin - seen that once.

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Re: T41 Dim Display

#9 Post by Geoffzie » Mon Dec 26, 2011 8:33 pm

Well, I've rechecked the fuses ... all OK. I also checked the video cable and motherboard socket with a magnifying glass ... also OK. I even looked over the ENTIRE motherboard with a magnifying glass ... looking for burn marks or burnt chips ... but nothing.

I really don't know where to go from here (without wiring diagrams or something). Before purchasing another motherboard, I was hoping to verify that the problem is REALLY in the motherboard and not something else ... like a grounding problem.

Like I said before, I'm finding quite a few people on the web who are having this same problem with various model Thinkpads ... but no one has any solutions.

Any other ideas before I "bite the bullet" and buy another MB?

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Re: T41 Dim Display

#10 Post by poshgeordie » Tue Dec 27, 2011 7:09 am

Here's what I've tried ... 3 different inverters (one known good tested one) ... 2 LCD's (one known good one) ... 2 ribbon cables ...
Can you confirm that you have a known working screen set (LCD, correct ribbon cable, and inverter) which all worked together before this, . If you can't be 110% certain of this then your problem could still be ribbon cable related.

You're certain you have 1 good LCD and 1 good Inverter (any R5x/T4x inverter is OK regardless of the screen size for this experiment).
In that case it leaves a possible issue with the ribbon cable, that is you have either the wrong cable for the LCD type, or the right cable which is broken.

Do you have any other working R5x/ T4x's part to either take the screen assembly off, or better to test the screen parts you have?

If you're not sure about which cable goes with each LCD, could you tell us the FRU part numbers for the LCD's and Cables and we'll then match them for you.

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Re: T41 Dim Display

#11 Post by Geoffzie » Tue Dec 27, 2011 10:04 am

I guess I could start by making sure I have all the right parts ... these laptops coming from eBay, who knows WHAT I have.

OK, the part numbers are:
LCD: 14.1" Samsung - IBM P/N: 11P8351
FRU P/N: 11P8352

Ribbon Cable - ASMP92P6713

Inverter (Replacement - Tested) - IBM P/N: 39T0369
FRU P/N: 39T0368

Inverter (Original) - IBM P/N: 27K9950
FRU P/N: 27K9949

I DO have another R51 with the 15" screen ... but I've finished it, it works perfectly, and I'd hate to mess it up. I also don't know if you can test a 14.1" screen on a 15" motherboard ... is that possible?

I buy these for resale ... so I may just buy another working 14" R51 ($35 - $50) from eBay. Then I'd have a working model to verify that my existing screen works.

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Re: T41 Dim Display

#12 Post by poshgeordie » Wed Dec 28, 2011 11:56 am

Not time at the moment to check the part numbers, but yes a 14" screen assembly works fine on a 15" and vice versa.

If you're not sure that all the parts you bought off eBay work then you need to start with a known working set up and eliminate the dud parts, whether stripping the existing working machine or buying a new working machine.

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Re: T41 Dim Display

#13 Post by Geoffzie » Wed Dec 28, 2011 3:09 pm

I've already bought a good working R51-14" from eBay ($45) that boots to Bios OK (less hard drive & ram). I should get it within a few days.

I'll then have a known good LCD, LCD cable, inverter, and good motherboard ... I can then determine what exactly is wrong with the present one.

Thanks for all your help ... I've done a lot of Dells ... but only a few IBM/ Lenovo's. The thing is, ThinkPads are harder to sell because of their plain-jane looks. Seems people don't care how they run ... just so they look flashy! ... some folks are strange!

I'm retired, so I simply sell these on the side for "vacation money"

I've got an R61e Widesceen with Vista that I really like (bought it in boxes) ... especially the keyboard.

Good little machines!

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Re: T41 Dim Display

#14 Post by Geoffzie » Mon Jan 02, 2012 1:37 pm

OK, so I received the 2nd Thinkpad R51 from eBay. I installed the hard drive loaded with XP and checked it out ... everything works.

Then I removed the 2nd known good working 14.1" screen, and installed it on the 1st Thinkpad R51 ... again, dim screen. My conclusion: it's something in the motherboard.

Then I took the screen from the 1st Thinkpad R51, and installed it on the 2nd known good working Thinkpad (I only ran it long enough to see if it worked - I didn't want to damage the NEW motherboard) ... and ... DIM SCREEN???!

So maybe there's something wrong with the screen AND now .... the motherboard on Thinkpad #1. I'm thinking that something in the screen assembly (LCD or Ribbon Cable) is causing SOMETHING to blow on the motherboard. I've used 3 different inverters, so I don't think that's the problem.

I re-assembled the 2nd Thinkpad R51 (it still works fine) and finished installing programs and ran all my tests, battery charge, run on battery, memory tests, etc.

I'm going to quit there ... I've got a good working R51, and I don't want to damage it by testing questionable components on it. But I still have no answers for the 1st Thinkpad's dim screen.

Hope someone finds a solution for this ... for someone else's sake.

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Re: T41 Dim Display

#15 Post by RealBlackStuff » Mon Jan 02, 2012 2:03 pm

Looks like a dying/dead motherboard.
I've got tested, working R51 motherboards, see my 'signature'.
Lovely day for a Guinness! (The Real Black Stuff)

Check out The Boardroom for Parts, Mods and Other Services.

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Re: T41 Dim Display

#16 Post by laz440 » Wed Nov 04, 2015 12:15 am

i hoping you guys can help me i have gained whist doing some work for someone an ibm thinkpad R51
i know not alot when it comes to laptops but i know it came from a local refuse site intact but would not power but upon taking apart noticed some burt spots on the motherboard.
so i brought from ebay another motherboardit said a R 51 type 2887 fitted working great except new m/b had no 1394 socket so i have now lost the use of an otherwise unuseful port (to me at least).
i found out the 40gb hdd was the original with xp original backup load on it.
i found it 2 gb ram and a 120gb hdd (due to funds and lack of knowlege i did not go any bigger).
and one day i was leaning on the keyboard near the side fan for the cpu and the backlight lit up and i stopped leaning and my backlight went back off and idea what might cause it.
i have tryed a looking fr a loose connection.
seems fitted ok and windows 7 is ok on it but it keeps losing the video card drivers and trying to find software again could it be a fuse as mention futher up or could i need another m/b seems fine on an external monitor and evertime i lean on the heatsink is NOT very good for the cpu.
i need some advice in bite size chunks i know loads about PC towers and desktops just not enough about ibm's (or laptops beside ressurrecting them).

thanks for your time

Laz

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