TIG button PCBA design

It's clear that the original PCB and moulded cover don't exploit the available space fully. And as I'm planning to cram more stuff into the available cavity in the handle, I should design my gubbins to maximise the PCB size rather than blindly copy over the original dimensions.

This should fit OK. 

Perhaps I will 3D print a dummy part and check the fit. It's a std 1.6mm board thickness. That should work:

Buggering about with the edge connector fingers was probably the most time consuming activity so far by quite a long way:

EasyEDA has an autoplacement feature, so I can do a rough placement just to see if there is any chance the whole circuit will actually fit on the board, ideally on the top side only:

Looks almost workable, although the relay seems to have been dumped on top of other compts. I'll need to lock a few of the major compts in place and see what the other smaller compts get up to.

I will need to do a sanity check to see if the 5 way (external) edge connector has ended up getting swapped end to end, as that's a fairly obvious fuckup candidate. And indeed, it seems to be correct. Nobody knows why - but the result stands either way:

The arc enable signal comes in to pins 1 and 2, which seems to have been replicated here.

I need to do some initial placement of the critical / key compts (relay, IC, PSR pads, pots etc), then move on to placing the remainder and routing the lot together.