Lower oven has a mechanical t-stat and being a Hotpoint/GE most likely no adjust screw in center of t-stat to adjust, most likely just an adjustment of +35 to -35 degrees by changing the adjustment on the back of the oven t-stat knob, (was 85' off, changed by as much as possible 35' = still 50' off).
Could have a double line break relay bad on the oven controller for the top oven which would be just one part to fail and cause both bake and broil to not work or as Samurai said, check the tech/wiring diagram for hi-limit t-stats that might be common to both bake and broil for the upper oven. Looking at the parts for this unit on RepairClinic it looks like there are 3 different limit t-stats, one would be up in the console area and the other two most likely on the back of the oven, (one for each oven). None of them have a reset button and I don't know if any are a thermal cutoff that won't reset when cooled down. Even if they are the type that reset themselves they could be bad.
Edited by Budget Appliance Repair, 27 November 2013 - 06:50 AM.