I just fixed my GE oven (made in '98), and discovered several useful things.

The symptom was nearly zero heating on the bottom element. The element and temp sensor checked OK. Relays on the control board were clicking, but power to the element turned off at 12 sec. I saw a note on this symptom, recommending to change the electrolytic caps on the control board. I know they have a limited life- so I changed the four aluminum electrolytic caps. The oven started working. Good.

While I was troubleshooting the control board, I saw a fractured solder joint under one of the front panel pushbuttons, It turned out to be under a switch had long worked intermittently. I then saw that most of the leads on the other switches were cracked, too. As designed, the leads bore the stress of the key press (wrong, wrong wrong!). The solder on the leads was a thin sheet which bridged but didn't fill the though hole via. The repeated mechanical stress on the switch leads caused the thin solder web to fatigue and crack. I re-soldered the joints, filling the via with solder. Voila- like new- now every key press works every time!

Hope you guys can use this.