To repair double oven doors, replace the door gasket and any broken oven door glass if the issue is that the unit does not heat properly. If the oven doors do not close properly, check the hinges and door springs and replace them with new ones as required.
Before beginning any oven repairs, disconnect the power supply. For ovens that do not heat to the desired temperature, check if the rubber or silicone gasket lining the edges of the door is worn out. If so, carefully remove the old lining and fit a new one. If there are any cracks in the glass of the door, this will also need to be replaced.
If the oven doors do not close properly, open the doors and check the hinges. Pull the door straight up and out to release the hinges attached to the oven door or remove the screws holding the hinges in place. Replace the hinges with identical new ones. Screw the new hinges to the door or push the door downwards to reattach the hinges as required.
Examine whether the door springs are broken. If they are, then open the ends around the bolts with pliers, replace the springs with new ones and tighten the ends to the corresponding bolts.