Thanks for the support @Paulcheffus @Dyltone , really appreciate it! Maybe I should have started with something a little more simple for my first electronics project :)!!
Ok so buying a multimeter today, guess it's a gd thing to start building up my electronics toolkit if I plan on doing more projects no idea how to use one though :)! (already got a soldering iron, which I also need practice with!). Silly question when I'm testing the 12v barrel jack, and in general when usually the multimeter, should the plug be switched on at the wall? Don't want to electrocute myself ;)! I think I understand how to test the DC power supply but if that is ok how would I use the multimeter to test the CPT as the 5v output is a micro USB connector?
Dyltone thanks for the advice re 12v power supply, mines an outside ground so pretty sure my DC panel connector is wired up right as the positive cables are attached to the inside connector. Only question is my negative attached to the right connector? The empty pin seems to have an 's/c' written on it?
The weird thing is the 12" monitor is attached directly to the 12v in through the DC panel connector (I.e. Doesn't go through the CPT) and there doesn't seem to be any power going to that either which would suggest no power is entering the picade, so either the DC power pack is faulty (unlikely) or my crimp connectors are not making proper connections (possible :)) wondering if soldering to the DC panel connector and mom switch would be better? Just concerned that seems pretty permanent! The other thing that would support this is when I bypass the CPT and plug an RPi plug directly into the ATXraspi I do seem to get some power as a red light flashes on the pcb but again no backlight on mom switch and pushing the button does nothing which could indicate the crimp connectors.
The only other thing i was wondering was whether I damaged the ATXraspi when soldering the USB port and jumper pins. It was my first experience of soldering and I wasn't very good, although the solders look ok I think the iron was too hot as slightly scorched the pcb around the connections. Don't think I caused any shorts but you never know.
Any thoughts? Will test the DC power a little later if you can let me know about whether power should be on/off at the wall and how to test CPT micro USB I can start there :)!