Hi Chip,
You could check that the header pins on P-100, P-101 and P-105 again for dry joints.
Also check out the looms that goes from P-100 & P-101, this goes to the pricing board and the dislay.
Make sure that you use safe handling practices when handling any of the boards, especially the CCC.
You might have checked the looms for continuity but if a connection is not making correctly in the molex plug then you will have issues.
If you look at the plugs you will see a series of slots on one side of the plug. In these slots are the locking pawls for each connector, to remove a connection push back the pawl with a very small screwdriver or craft knife. Pull on the cable to withdraw the connection and reset the pawl, this is best done with a craft knife, you will see that the connection is a folded over design, if you unfold this slightly it will make a stronger connection when back in the plug (also check for any tarnish).
If you go through each connection in turn then you know you will have good connections in the looms.
Please let us know how you get on.
Regards
Alan
Alan Hood
ami-man
UK