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ThinkPad X32 IPS LCD Retrofit

Written 9/20/2012

If you know me, you know I'm a real stickler for display quality, especially with color gamut, contrast, and viewing angles. As a ThinkPad aficionado my favorite laptop I've ever owned has been this ThinkPad X32. One glaring problem stands out, however, and it is the quality of the LCD screen. Oddly enough, aside from a slim selection of built-to-order options, modern notebook displays haven't really improved on the problems posed by this one, and in some ways have gotten even worse!

The biggest issue with a typical twisted nematic (TN) LCD is certainly viewing angles. Some better TN displays are not so visually offensive, but a typical one, especially one found in a laptop, is unlikely to have angles suitable for enjoyment of anything but plain text. Sometimes the angles are so poor that, when viewed straight-on, the top of the screen may have a different bias than the bottom, rendering blacks blue-ish and gradients inverted at times. Horizontal angles are typically more tolerable, but still leave a lot to be desired. Contrast has been improving steadily over the years, but black levels are still higher than preferable. Now that white-LED backlights are becoming standard as of 2012 in notebook displays, red colors are often subdued and washed out.

Back to the X32. It has a TN display, and suffers all of the drawbacks one may expect from it. I have a nice little box labeled "LCDs", and in it are a handful of X41 tablet assemblies. Pen tablet laptops stand out to me not because of the input capabilities but rather because they frequently contain in-plane switching (IPS) LCDs or patterned vertical alignment (PVA), which offer superior contrast, color balance, and viewing angles over a TN display.

The X41 tablet LCD features a 12.1" dimension, the same as the X41, but more importantly the X32... Upon disassembling the X41 tablet display assembly and removing the touch digitizer, I had an LCD that looked physically similar to the one in my X32. The plug even fit. Unfortunately, for whatever insipid reason the pinout is reversed! That means I could get it to work by taking the LCD ribbon cable and twisting it around 180 degrees. That's awkward, but it shows electrical compatibility. Here it is running, inconveniently, a Street Fighter game, in this twisted state:

Other people have done a similar modification, retrofitting an X41 or X6x tablet LCD into a regular X61. The same issue with the cable is present, and the common solution is to construct an adapter or purchase one. I, however, only had an hour before class, and my laptop was in pieces, so I took a far more DIY approach and soldered a reverse connector right below the original:

To my shock and joy it worked the first time! It does not look pretty, but is quite stable.

With the most challenging part out of the way (so I thought), I set out to deal with a new issue: the LCD panel is physically not the same shape as the X32 one. That is, there are mounting tabs parallel to the display surface sticking out of the sides, rather than screw holes on the sides themselves. I could clip those tabs off, as many do, but unfortunately the original mounting brackets would not be able to attach with screws as intended by the original X32 design. So, I grabbed my original TN LCD and got cracking.

On the left is the TN original and on the right is my new IPS panel, with soldering all complete.

My plan was to take off the metal front frame of the LCDs, and swap the physical LCD panels themselves, control and driver circuitry still attached, and leave the backlight intact in the frame. That way, I could use the original TN panel's backlight (which was in better shape than my X41 one I chose) and mount it using the original parts. That way, the X32 can be easily returned to stock, and the LCD is a drop-in replacement.

Frames removed, ready for swap:

Post-swap, everything set up nicely:

I later had to insulate the exposed controller board. Fully assembled, a few capacitors on some data lines would hit the back of the ThinkPad top shell and be tied to ground, causing the image to go pasty white and inverted. Some electrical tape solved all of that...

Here is the "new" panel doing a first boot:

All happy on the desktop, looking good with colors:

With the front bezel on, everything is stock on the outside, except these angles:

Another fully assembled shot:

All in all, this went a lot smoother than I thought and wasn't too hard. If I ever get my hands on a 12.1" SXGA+ IPS panel I would love to do the same modification, maybe in an X61 or another X32 (with appropriate video bios modifications in lieu of EDID data).

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