Replacement parts for WHIRLPOOL RBD275PDT10 | AppliancePartsPros.com

Here is a tech sheet and a service manual
https://www.servicematters.com/d...0Sheet%20-%204451887.pdf
https://secured.whirlpoo...4ddde3385256a7e00524e76/$FILE/8178007.pdf

could the connector to the keypad be loose?
Possible. Or it could be that the ribbon cable was not all the way in the connector when it was locked in. But since you are getting the same error code as the original fault this is doubtful. Could try cleaning the connector on the control board (see below), also check that the pins in the connector look OK. A magnifying glass will help. Sounds like you may have a bad solder joint or a cracked track on the control board. Remove the control board and wiggle the ribbon cable connector while looking at the back side of the board to see if any of the pins move. Bad solder joints often have a dull color or pin holes. Again a magnifying glass helps.

do I need to replace the transformer?
I doubt this a bad transformer would most likely kill all power to the control board.

and/or replace the control board?
May have to do this if you cannot find a bad connection and cleaning does not help.

RIBBON CABLE CLEANING
Unplug the unit
Open it up
Remove the ribbon cable from the keypad to the control board at the control board.
Clean the edge connector.
If it is the type where there is not a connector just the insulation is removed, it can be cleaned with a pencil eraser. Do not use an ink eraser as it is too abrasive.
Check the tracks in the ribbon cable for hairline cracks. A magnifying glass helps here.
Would not hurt to clean the connector on the board. Use electronics contact cleaner or isopropyl alcohol and a tooth brush. Be gentle and do not reconnect till all the solvent evaporates.
Reconnect everything and give it a try.