Need to do a few things to the Axiom PB-0555 PCB before we can install it into the ECM.  One thing that was needed to be added is pull-up resistors on some of the SPI CS lines.  These were missed on the main PCB and it is a lot easier to install them on the actual Axiom board.  Being that the +5 volt supply is the same for the main PCB and the Axiom we don't have to worry about supply turn on issues.  A 10 pin bussed 10k SIP resistor package also gives us a few extra pull-ups if needed.   Block AA and Block Z show these pull-up resistors.
     Also need to remove the straps to the MPC-555 ADC so that the ADC can be referenced to the precision reference on the main PCB.  An input power header needs to added also along with isolating the original +5 volt regulator on the Axiom board.  While looking at it I also noticed that the hex bails on the RS-232 jack were never even tightened up.  It certainly would be nice to have a hunk of metal floating inside the ECM.  Finally the MAX-232 serial interface IC needed to be isolated from the MPC-555 I/O lines.  The main PCB (Block O) has its own serial interface driving the outside world and that will be our main communication path.

NOTE: The ADC Noise Fix page has a modified +5 volt reference configuration.