I have discovered something particularly interesting that may be relevant to the interests of people hoping to mod 2C's to 2B's. I am temporarily in posession of stryker7314's 2B DVI board while I attempt to repair his damaged backlight driver circuitry (probably just a blown mosfet or something). While I was examining the board though, I noticed something particularly interesting. A couple pictures will illustrate well:
Here's a close shot of the DVI to eDP portion of my 2C DVI board:
Warning: Spoiler! (Click to show)
And here's an equivalent of stryker's 2B DVI to LVDS board:
Warning: Spoiler! (Click to show)
If you examine these two boards closely at this section, you'll probably notice that the big main chip (which is a DVI receiver made by Explore Microelectronics) is present on both; immediately to the left of this chip on the 2C board however is a second chip, labeled IT6251. While I'm unable to find a datasheet on this particular part, I can make a pretty good guess based on the manufacturer's products combined with its placement on the board; it's a 2-channel LVDS to 4-lane eDP converter chip. Why do we care?
Because it means a 2C PCB has all the important components already there to drive a 2B panel and timing controller.
Now, closer examination of the boards reveals that in the 2C they're only using half of the output LVDS lanes (running in 2-channel mode) provided by the EP269 compared to the 4-channel mode on the 2B (indicated by the larger number of resistor packs marked 750 on that board). I don't have a datasheet yet for that exact chip, but a closely related datasheet (EP263) shows that mode selection between output formats is simply chosen by holding a couple pins high or low. By modifying these mode pins on a 2C board's chip and rewiring the output from the chip, we can drive a high refresh T-con by
bypassing the ITE LVDS-eDP converter altogether.
Now, this is obviously a highly skilled and labour-intensive mod; you'd need to desolder the 750ohm resistor packs to detach the output from the EP269, solder the mode lines to whatever is required to enable all 4 output channels, then solder a few ribbon cables from the left half of the EP269 to a small daughter board containing a few passive components and a couple 2B style connectors. Once *that* is done though, all you need is a source for the two cables and a T-con (which there seem to be a couple viable sources through taobao, I'll update later with my experience here letting you know if it's a valid way to source the boards) and your previously 2C monitor should overclock with aplomb.
I know this is probably over the heads of a lot of the people reading here, but the take-away point is that assuming you can find somebody with the soldering skills (I doubt I could do the mod for all those interested, although I can pioneer it and produce a guide) it's actually possible to convert a 2C DVI board into effectively a 2B DVI board, solving half our problem (and all of it if you can get a T-con). Sure, it'd be easier if Scribby can source the boards and we can do a drop-in replacement - but worst comes to worst there *is* another way
I still need to scare up a copy of the EP269's datasheet, so if anybody comes across it *please* let me know!
As a bonus, while examining the boards and connectors I was able to
pin out the LVDS connectors on the 2B PCB if it's useful to anybody. Combined with the
SLA1 datasheet, this allows you to reproduce the cables fairly easily if we can't find a ready-made source.
