@ GadgetUk
I've just done the mod's to my 138 in 1 cart - took ages to come from AliExpress and the quality is not as good as the 161 in 1 either.
That aside, I set about applying your cap fixes, etc. Then decided to house the dipswitch on the top front of the case - minimising trailing wires and keeping my OCD under control.
Couple of things which may be of interest to people:
(1) Used 180uf caps at the JP2 connection and just below the C1 chip.
(2) I don't have a hot glue gun so used a clear plumbing silicon leak sealer (LS-X in the UK) to stick the PCB to the underside of the top half of the case, and surprised as to how secure it is.
(3) Dremelling the hole in the top of the case to allow the Dipswitch to come through - you also need to trim up the plastic to create a recess for the pcb to sit as the vent plastic is quite thick. If you don't - only half the height of the Dipswitch will come through fowling the switches from operating. Note:- There is loads of space/clearance under the case.
Here is some pics below, Enjoy -
Finally, I filled the hole in the side of the case where the cable came through also with LS-X.
Very pleased with the mod.