This is a method of taking apart the Logitech K750 solar powered wireless keyboard. If you just want to replace the battery, you do not have to take the keyboard apart. There are several online instructions on how to remove the battery tray to replace the battery.
But if you really want to disassemble the keyboard, you have come to the right place. I disassembled mine because I spilled alcohol on it and it stopped working. I took it apart to clean up the mess and it worked after that. Anyway, the only instructions I could find online is a youtube video of a person taking it apart by essentially destroying it. That is not really what I want to do since I would rather prefer to fix it and use it further.
Tools: #0 philips screw driver; tools to pry open latches (small flat hed screw driver works but may cause cosmetic damage.
Anyway, let's get to it.
Step 1: Peel Off the Top Plastic Film.
You can think of the keyboard as having three layers. The top layer is a thick plastic film, the bottom layer is the base of the keyboard (white on mine), and in between those two is the main layer that has the chicklet keys, solar collector, and the small circuit board.
The second (main) layer is attached to the base (bottom) layer by 27 screws (if I counted correctly). To get access to the screws, you have to peel off the top layer.
The top layer is attached to the middle layer with double-sided tape. The tape covers 100% the back of the top layer, not just a few strategic spots. The top layer is fairly thick and robust, but you should be careful in peeling it off anyway.
Turn off the keyboard.
Start peeling by prying at a corner with something flat and somewhat sharp. Once a corner is up, you can peel back the top film slowly. Try not to mess up the double-sided tape too much because you will need it to be good enough to stick the top layer back during reassembly.
Step 2: Remove the Screws.
There are many screws holding the main board to the bottom. On my 2010 version of K750 there are 27 screws in total--7 black screws with fine thread and 20 shiny steel screws with coarser thread. Take note of where the different color screws are before removing them. Use #0 philip screw driver.
Note: After the screws are removed, the main board is still held in place by latches, so do not force it out carelessly.
Step 3: Undo the Latches.
Still holding the main board to the base are several side latches and one center latch. Leave the center latch to the last.
Pry and pop off all of the side latches.
For the center latch, use a small screw driver and push the latch tab towards the center of the board.
The main board should now be removable from the base. If it is not easily removed from the base, check that you did not miss a screw, or that sugar from the coffee spill 6 months ago has become yucky adhesive.
Step 4: Remove the Battery Tray.
Remove the battery tray from the base.
Step 5: Circuit Board.
The circuit board on my K750 is not removable. Although the cable ribbon from the keyboard can be detached from the PCB. To detach the ribbon (maybe to clean the contact points), flip up the latch with a small screw driver.
Step 6: Reassembly.
Reassembly is mainly the reverse steps except for the battery drawer, which should go in last after everything has been assembled.
1. Snap the main board back onto the base.
2. Insert the screws and tighten. If you have two different types of screws, make sure you don't get them confused. Here is a general technique to prevent cross-threading: Slowly turn the screw counter-clockwise first until you can feel a click, then turn the screw clockwise until snug. Do not over-tighten--for screws without torque specifications, I would err on the loose side than risk stripping the threads.
3. Attach the top film layer--but first inspect the double-sided tape and tidy up/cut out any spots that the tape has folded over and has become stuck to itself. This is because a folded-over tape will be thicker and will make the film feel bumpy. Chances are that the film will be a little bit bumpier than before, so be prepared to accept that. Otherwise remove all old adhesive tape and apply new 3M double adhesive tape used for cellular phone LCD repair. It will take a lot more effort.
4. Insert the battery tray. The positive side (most likely has a warning sticker stuck on) faces down, i.e., after everything is said and done, the positive side should face the table.