Bottom element not heating

First checked voltage to element and only getting 120 volts.
Checked web site for problem and 23% said heat sensor. Replaced heat sensor and did not fix problem. Replaced circit board and fixed problem. Solder point on relay on back of old circit board was burned. Might could have resoldered but already had new part before we took the old one out. Spent extra $50 and 2 days when should have taken out circit board first.