ok here is what you have to do to figure out what is going on, you have a voltage issue to the ui board you will have t o find, considering you replaced both boards with the correct part numbers, then do the tests below, it could be you just got a corrupt part or you did not use a grounding strap when handling the boards and fried one with static electricity:
UI Board Diagnostics
1. Check for 120 VAC at IMC J101 pins 2 & 3.
a. If 120 VAC is present go to step 2.
b. If 120 VAC is not present check house supply voltage.
2. Check for 12 VDC between IMC J603 pins 1 & 4 and 7.5 VDC between IMC J603 pins 1 & 3.
a. If either voltage is not present replace the IMC board.
b. If both voltages are present go to step 3.
3. Check for 12 VDC between UI J201 pins 1 & 5 and 7.5 VDC between UI J201 pins 3 & 5.
a. If either voltage is not present, check wiring between the UI board and the IMC board.
b. If both voltages are present, replace the UI board.