Toward a QXGA T70: The IAQX10M

The T70 is about six months old, and I finally got around to buying one of the boards. I suppose it's time to build out the rest of a full fledged T701 :-)

Just like the BOE/Hydis SXGA+ HV121P01 AFFS screens are the desirable screens for an X62, every T70 builder wants the legendary IDTech QXGA IAQX10. The only ThinkPad this screen was ever offered in was, of all crazy things, the R61. It never appeared in a T-series, and wasn't used in many other laptops either. For a while there were surplus IAQX10N and IAQX10S models available on eBay, but those seem to have dried up.

That said, eBay and AliExpress are still full of the IAQX10M industrial model. It appears to be the same glass matrix with a slightly different controller, films, and a relatively large frame. It's about 2cm wider and taller than the laptop version, and more than twice as thick. There's no chance of fitting it in a laptop lid without serious modding. Of course, I'm not afraid of serious modding.

There's another problem to fix first. A ThinkPad (T70 included) won't even try to boot an LCD that doesn't respond to EDID (or responds with an invalid EDID for that matter). The IAQX10M is missing the EDID electronics present on the other versions and simply ties the EDID lines high.

0402 SMD is annoying, but it's not too hard to add the missing EEPROM (a standard 24C04), 4k7 SCL/SDA pullup resistors, a .1uF decoupling cap, three jumpers to tie the address lines to ground, and then move the jumpers on pins 4,6 and 7 to connect EDID power and un-tie the EDID lines. Removing the big capacitors around the 0402 pads and putting them back after adding the smaller components makes things considerably easier.

At this point, the ThinkPad still won't boot the panel, but it's possible to boot an OS (say Linux) with the blank pannel connected. Once the machine is on the net, it's no big deal to ssh in and flash a working EDID according to the instructions at ThinkWiki. Flash, reboot, working screen!

Now for the mods needed to make them fit.