Here are your parts
Replacement parts for FRIGIDAIRE FDB1050REB2 Frigidaire/dishwasher | AppliancePartsPros.com
Here is the tech sheet
Often long wash times are due to the unit trying to reach a temperature set point and being unable to get there.
Try a cycle that does not include water heating.
Chjeck that the incoming water is at least 120 degrees F.
Could be the heating element, the hi-limit thermostat, the thermistor or the control board.
Try running diacnostics to see if that gives you some clues.