The new version of the Dualshock 4 controller has several upgrades over the original, including a translucent strip along the touch pad to allow the light bar to shine through. Physically though, the controllers are very similar, as noted in my teardown of the new controller.
Having bought an Anniversary Edition controller with a faulty analogue stick, I took the opportunity to upgrade the controller to use the internal components from a brand new black controller.
Preparing the Shell
Removing all of the parts from the two controllers, it is easy to compare the differences between the two shells. The main difference is the position of the plastic bar which holds the touch pad in place. In the new controller, this has been moved down slightly to accommodate the plastic piece that transmits light to the touch pad.
Carefully remove this piece (I used a craft knife), taking care to both keep it intact, while retaining the two parts that overlap the shell at either end. Keeping these sections on the strip will make it much easier to position the strip when it is glued back in place.
The other change to the shell is with the separator between the L1/L2 and R1/R2 buttons. On the old controller, this is part of the shell itself and is therefore the same colour as the shell. On the new controller, it is built in to the button assembly, and is the same colour as the buttons.
Cut this section out of the old shell, leaving the edges flush with the inner edge of the shell.
The new parts can now begin to be fitted into the shell.
Inserting the Touch Pad
Before the touch pad can be inserted, the plastic strip that was removed earlier needs to be glued into place.
To position the bar, use the shell from the donor controller as a guide. You could measure the position of the bar, but it is not necessary to do so. It is a good idea to mark the shell with the rough position the bar should be fitted, to make it easier to place once you have added glue. I would recommend doing a 'dry fit' with the touchpad in place, to check the cable is accessible. Depending on how the strip was cut, either the overlapping sections will need to be trimmed slightly underneath, or the bottom of the strip might need to be sanded down slightly.
Once you are confident with the positioning, add a small amount of ABS glue to the overlapping ends of the bar. This can be picked up cheaply; I used Evo-Stik pipe weld.
With the strip in place, the touch pad can be fitted. If you want to change the face buttons, now is the time to do it. The new controller has grey buttons compared to the original black ones, and third party replacements are available in a variety of colours.
With the touch pad in place, the rest of the controller can be put back together.
This is a fairly simple task, as the board and shoulder buttons are attached to a plastic 'skeleton', which holds everything together. The cable from touch pad needs to be carefully pushed through the slot in the 'skeleton', which is a bit fiddly - used a spudger to poke it through.
The 'skeleton' should slot back in place with a little force. If it doesn't, check the silicone pads on the face buttons are in place correctly, and the shoulder buttons are not obstructed by any excess plastic still left from the section that was removed.
Screw the board back in place, and ensure the battery holder is clipped in correctly.
With a bit of work, it is possible to upgrade the battery to 2000mAh, though this is no longer plug-and-play like it was with the old controller. A guide to upgrading the DS4 v2 controller battery can be found here.
If you don't want to do this, proceed to clip the rear of the controller shell back in place. The shell is not a perfect fit, and will leave a small gap around the top seam.
I haven't been able to figure out what is causing the obstruction, however the gap is only small and is not noticeable during use. Making sure the screws are done up tightly helps to reduce the gap.
Below is an image of the final product, connected to a console.
With the rear of the shell back on, you can now enjoy your newly upgraded controller.