White screen after screen replacement -

[wisdomkeeper]

I had LCD display with one of the ribbon cables between LVDS board and LCD faulty. I bought LCD replacement from IBM T41. I've used the old cable from the faulty LCD with resolution 1400x1050 with the new screen with resolution 1024x768. The main ribbon cable conector fits perfectly in the 1024x768 LCD display, but when I turn on the laptop, I see only white screen OR the laptop shuts down. I would like to know - Is there a different cables for different resolution LCD-s in the IBM T41 series and how to bypas the problem. I just can't wait another couple of days to order LCD cable and wait for delivery. I can't find the pinout of the ribbon cable.
NEW screen FRU - 92P6731 P/N 92P6730
OLD one - FRU 11P8345 P/N 11P8345

[Neil]

Is there a different cables for different resolution LCD-s in the IBM T41 series

Yes...but, if the connector on the back on the panel is seated properly, you should still get an image just not the right resolution. A blank white screen usually indicates that the cable connection is not good. Maybe came loose during assembly, or offset by 1 pin, or something.

[wisdomkeeper]

I bought 1024x768 LCD ribbon cable, but even with the new cable, my IBM T41 shuts off when I connect the new 1024x768 LCD matrix. After that, it refuses to power up if i don't cut the power and disconnect the LCD. So - it doesn't want to work with the new LCD. When connected to external monitor, my IBM T41 works perfectly, but it's not the solution for me.

[RealBlackStuff]

You originally had 14.1" SXGA+ with LCD-cable 91P6787
The 14.1" XGA screen needs LCD-cable 91P6786
AFAIK an SXGA+ cable also has more wires than an XGA cable.
By putting the SXGA+ cable in the XGA screen, you most likely destroyed some of the screen electronics.
Time to download the HMM and read it: http://download.lenovo.com/ibmdl/pub/pc ... 192_01.pdf

[wisdomkeeper]

By putting the SXGA+ cable in the XGA screen, you most likely destroyed some of the screen electronics.

XGA and SXGA+ cables are identical. I counted the wires myself, the only difference between XGA and SXGA cable is on the side that is plugged into motherboard - some SMD elements, most likely connected with LCD timings/resolution recognition.

[ajkula66]

XGA and SXGA+ cables are identical.

No they are NOT. Period. End of story.

[wisdomkeeper]

No they are NOT. Period. End of story.

I said - EXCEPT. The number of the wires is the same. The difference is trivial - SMD elements, soldered near the connector, that is plugged in the motherboard. I found out that they are used to distinct different LCD panel resolutions, prior to EDID chips on the LCD PCB(T60-s and later) Physically, both cables use the same interface connector from the mobo side and the same 30 pin interface on the LVDS LCD PCB connector. This is why I don't think thay I could fry the LCD with either type of cable

[automobus]

Physically, both cables use the same interface connector from the mobo side and the same 30 pin interface on the LVDS LCD PCB connector. This is why I don't think thay I could fry the LCD with either type of cable

I had two T23, both with wireless antenna and SXGA+, and even a Ultrabay Numeric Keypad. One screen was yellow, and I wanted to replace it with a bright healthy screen. I did read advice to check interface pin assignment (pin-out) in datasheet, but I could not find any data about my subject screen. So I did the best I could, poked it with a multimeter to check that it is identical to original screen. I thought it was safe. I proceeded to ruin both of my T23 planars. At that time, the cheapest replacement board I could find was sixty USD on eBay. I then sold the lids and keypad, because I felt so guilty for ruining two ThinkPads, someone else deserves these uncommon parts. A T23 with numpad remains one of my favourite laptops ever devised; I miss it, and I regret the mess I made.

Lesson: flat panel displays are not as inter-changable as one might think. Seemingly identical interfaces, should not be assumed identical. You may have ruined either your panel or system board.

[wisdomkeeper]

Lesson: flat panel displays are not as inter-changable as one might think. Seemingly identical interfaces, should not be assumed identical. You may have ruined either your panel or system board.

I don't know about the LCD panel. I will not connect it again with the motherboard. The cause for the white screen even I've installed new screen and compatible cable was a burnt fuse near the LCD connector on the motherboard. I found a schematic for all the fuses in the T4x series and after I checked all the fuses, I found the burnt one. I soldered piece of thin wire on it's place and everything works once again as it should.
Thank you all for the advices.