About that Hotpoint lower oven....
Does the clock for the range still work? If not, have a look at the dial for 'hours to cook' and 'start time'; if either dial has a setting marked MAN for 'manual' turn the dial until this position clicks in, then try the lower oven. I had a Hotpoint built-in years ago that suddenly stopped working after I had cleaned the control panel and inadvertently messed with the timer settings - but I 'fixed' it just by engaging that manual setting.