Decided to get the case base done. Measured everything out (the relevant thicknesses, including any awkward capacitors or whatever that are in the way and can't be relocated):
4 button holder (taller than the d-pad) 9mm
Rubber contacts and board for 4 button holder 6mm
PSone screen mobo 4mm
-spacer- thin PVC sheet 0.5mm
PSone console mobo 5mm
-spacer- thin PVC sheet 0.5mm
Battery thickness and holder (thicker than the PSone CD mechanism) 22mm
Therefore, total thickness is 47mm for internals, add on the thickness of the Plasticard case, top and bottom; total thickness 50mm.
Internal size of existing top casing is 20mm, by the time it was trimmed and sanded, so the backing case needs to end up 27mm thick, so it needs to be 30mm tall in real terms.
Placed my finished top casing onto mounting board, traced the outside of it. Naturally, the outline needs to be smaller so as to compensate for the thickness of the plastic.
The pics below are for illustration; the various plugs will be cut off, the memory card slot will be relocated so a memory card can be inserted into the system.
There is plenty of space for the batteries, the positions shown are only for illustration. Three batteries could fit into the system if the CD ribbon is relocated and the power plug for the CD too, but it adds the the difficulties. Two batteries should be sufficient, 4000mA in total, it looks like the PSone console takes about 1000mA, the PSone screen, when audio is working is around 800mA, so therefore I should get around 2 hours 10 mins playtime - sufficient. Always a trade-off with size, weight and cost!
CD placed on:
Next job is to cut out the shape on the orange mounting board, and make a clay mold which will be 30mm tall and have suitable recess to take a CD and memory card.
One more thing to mention, decided will just use stock PSone speakers for the system, will just fit in case, with a couple of the corners trimmed down a little. Mylar speakers are a bit better on audio quality, but the PSone's speakers are ok: as one of the aims on this project is to sell cases to others who want to make their own systems, it makes sense to use stock items, and after all, all the official PSone screens come with the same speakers! (standardisation). BTW - my NTSC screen came this morning from the good ol' USA, waiting for my Retro Duo now!