There were essentially two major hardware revisions in the era of the 750 and 755:
1) The 750 range, 755c and 755Cs share plenty of hardware which can be swapped between machines. Note - To some extent, much of the 750 and 755 hardware is shared with the 355/360 & 370C
2) The later 755 range is very different and includes the 755CD, 755CDV, 755CE, 755CSE, 755CV & 755CX and all share similar base hardware, although each one tends to have unique daughterboards making it what it is. An example of this would be the CD version which includes sizable daughterboards containing a huge deal of video and audio hardware to provide multimedia functionality.
You can download all the drivers for 750/755c/755cs here.
You can download all the drivers for 755CD, 755CDV, 755CE, 755CSE, 755CV & 755CX here.
You can download all the mwave software for the 755CD, 755CDV, 755CE, 755CSE, 755CV & 755CX here.
LCDs of 750C and 755c are compatible...
I broke my 755C LCD and wanted to find a replacement. During the past month, I tried different 10' TFT but didn't even think that 750C LCD is actually compatible although it has two sliders.
In dismantling various lids of various 750 and 755c machines I've noticed 3 TFT types of display and lid:
1) 750c has the back/top plastic of the lid, bolted to the screen which is attached to the hinges. It will have 2 sliders.
2) Early 755c machines will also have the top/back plastic removable, attached to the LCD panel which is bolted to the hinges. Only 1 slider - the other is blanked off.
3) Later 755c machines have the back/top of the lid bolted to the hinges and in this case the LCD bezel detaches like all later Thinkpad panels. Again, one slider.
So, this is how it looks like by putting 750c two slider TFT on a 755c
Basically the 750/755C LCD has 2 detachable inverter boards, one is for the backlight assembly (on the top of the picture), with the part number of INVC192, serving 2 CCFL. Another one is call "inverter board" by IBM also (bottom one), and the part number is PN53G9730, which has 2 sliders in 750C but 1 slider in 755C.
The backlight assembly has two CCFL. I didn't try replacing them with LED one, but apparently it's not easy to tear it down.
I believe the INVC192 is sold as a part of Hitachi LCD screen panel. And based on my experience, most of the black screen cases are because of a bad inverter board (but the CCFL bulbs always work)
Disassembly and reassembly of the LCD is pretty straight forward, and one thing you need to be careful about is that the connector connecting inverter board PN53G9730 and the screen panel (white one on the bottom of the picture). It's tight ,and you cannot see it while removing the inverter board.
Well, one last thing, if you want to replace the ccfl with some LED, I'm sure the black one is ADJ, and I believe starting from the orange one, the order is VOC (>10v?), ADJ, ENA(>3.5V?), and GND.
Sound Card
The sound card from the 750 and the 755c/cs are swappable. The 750's card is a little different by having a much larger chip on board and no 'microspeaker'. They use the same IBM driver and software and have the same leaky surface-mounted capacitors....
DC Power Board
These are also swappable. Some have 1 electrolytic, some 2 and some none, but they're all the same shape and specification (AFAIK).
Interposer
The interposers are the same between the 750 and 755Cs.
Keyboards and Plastics
The keyboards are largely the same between the 750 and 755C/CS and can be swapped. The bases are swappable but there are some small differences which you might not be able to live with. Obvously the Type/Model referenced on the bottom will be wrong. Particularly if you're swapping over a 360 base. Also, the 3.5mm sound jacks are either missing on the 360 or the plastic surrounding the top are different designs.
In the following image, you can see 3 of the similar machines stacked. It's clear that the 755 and 360 share the same design, with the 360 having it's audio ports blanked-off and the 755 having a plastic insert with the two 3.5mm jacks exposed. The 750 base can be used, but the audio connectors do not pass through an interchangable piece of plastic, and are sealed at the top by the keyboard bezel. These tiny differences mean that whilst all 3 bases are interchangable, there are subtle issues dealing with the aesthetics when trading plastics between machines.
Top Cover
The top cover which protects the keyboard connectors is almost the same between the 750 and the 755c. The difference is that in the 750, there are two tiny plastic extensions over the two audio jacks. Here you can see the 750 top cover on the left and the 755c top cover on the right:
