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Here is the wiring diagram
http://manuals.frigidaire.com/prodinfo_pdf/Lassomption/318045090.pdf

I am assuming that you checked for power at P5-5 to P5-8 and saw 120 volts.

I am sort of guessing on the above as it is not marked as power in for the control board power supply.

I would disconnect all connectors to the control board except P5 and then see if the display will light up.

Only other thing I can think of is that you received a bad board.

I rigged a way to hook 120v directly to P5 and P8 from a wall outlet. The oven control illuminated. This is true of my orginial and the replacment oven control.

However when it is installed in the range it does not lite up.

There must be some other component failure preventing power to the control board.

Blind luck resolved the probelm. What I did should not have fixed my problem but it did. Here goes.

On my oven control P5-14 and P5-15 connect to the temperature probe and thermal circuit breaker. There was a two wire plug that connected P5-14 and 15 to the temperature probe and circuit breaker. I disconnected the plug tried to jumper P5-14 to P5-15 at the plug. I did not have any alligator clips small enough to used so I rigged two cutoff nails into the plug and jumpered between them. No change.

I was not confident that I had continuity between the nails, so I decided to cut the plug out of the circuit, strip the wires and twist the bare wires together to make the jumper. No change.

Like a dummy, I cut the wires too short to reuse the plug. Not having a replacement plug, I used two cermanic wire nuts to reconnect the wires. When I powered the oven backup the electronic oven control lit up and has been working like a champ ever since.

I checked continuity through the plug. It checked fine. I took the plug to my local appliance repair man, told him the tale and he checked continuity through the plug and said it was OK. He agreed with me that removing the plug from the circuit should have had no affect.

I haven't got a clue as to what was wrong and I have no idea what fixed the problem. I hope my experience helps someone. Thanks all for your support.

P6 and P12 are the ribbon wire plugs. Neither are shown on drawing number 318045090. The drawing only shows connectors that are hooked to the stove wiring. Not all of the wiring is shown (wires to p13 for example). P5 is shown because it connects to the 15 pin connector internal to the stove. The stove connector is what is depicted in the pin representation at the middle bottom of the drawing (connector B). It also shows you how to count the pins

P6 and P12 use a press-in ribbon wire holder. The ribbon wire is not glued into the connectors. Grasp both sides of the top of the plug and pull gently up. The top will release and remain in the plug. The ribbon wires will be free to remove. To reconnect, install the wires and push gently down on the top of the plug, it will lock the ribbon wire in.

The EOC internals are not shown on the drawing. The EOC is depicted in the thick blacked lined box on the drawing. There is no schematic for its wiring and internal components that I could find on the internet. I tried to get a schematic of the EOC internals from the manufacturer and was ignored.

Also my oven and your oven must be different. The only P5 pins on my oven that are not wired are 1,2,3, and 9.

Have a nice day.