Whirlpool side by side American Fridge freezer

Hi,
I have an S26s5 df, (8586 18153010, 110431027754) with the control board problems, as observed by many others in this forum.
I have replaced the capacitors on both boards and the main relay on the control board.Also, I replaced the start capacitor on the compressor.
Upon reassembly, I switched on, and observed the following.
Front panel flashing, 2 hyphens in freezer display, and 4 in the fridge display.Interior lights worked, and internal fans were operating. I heard the main relay click in but no compressor noise.I decided to wait, and after 20 minutes, the compressor kicked in,and it began to cool.(I assumed this may have been the unit doing a defrost cycle first).
I left this going until freezer temp got down to -17 on the display. By this time, the alarm had disappeared.
I accidentally pushed the standby button, and the unit shut down. Pushing the standby button again produced no result.
So, it all appears to be back at square one.
Not sure what to check next.
Any advice would be appreciated.