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Parts for Whirlpool RBS305PDZ8 Oven - AppliancePartsPros.com

See the attachment for the tech sheet.

First I would check the power. The elements require the full 240 volts and you may be missing half the line.
Below is my standard blurb on this though your is probably hard wired os will be a little different.

Try flipping the breaker off/on slowly a couple times. Sometimes you can loose half the line without actually tripping the breaker.
Check the voltage at the wall receptacle
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral, both should be 120 volts.
If OK
Unplug the unit and check the wires at the terminal strip in the machine to make sure none are loose or burned out
If OK
Check the power at the terminal strip.
Do this with the heater off and on.
[COLOR="Red"]Be careful as 240 volts is lethal !!![/COLOR]

Next I would check the thermal overload (item 37 in section 01).
It should be 0 ohms.

If OK then check the wires to/from the elements.

IF OK then you may still have a bad board.