I have an old (probably 1940s) Hotpoint stove/oven that came with my 1901 farmhouse. The cook-top works well enough to use but the oven runs in the neighborhood of 100 degrees F over what the dial is set to. I tested this with a new oven thermometer and when set at 300f on the dial, the thermometer reads just over 400f.
There is an adjustment on the back of the knob to adjust the oven temperature setting to actual temperature but it's already cranked all the way to the lowest setting. Are there power resistors inside this thing that have lost their ability to resist current and allowing too much voltage to the coils? I'm a fairly able electronic DIY'er having built several tube amplifiers & guitar effects over the years so I'm not adverse to tearing into the stove if I have to. It is a pretty nice vintage piece though so I'd rather not rip it apart if I don't have to.
Best Answer
You could try to replace the thermostat if you can find a suitable replacement. But there may be a very low-tech solution. If the oven temp is consistently 100 higher across the entire range of the oven knob, you can either repaint the knob to shift all the numbers over or you can paint an indicator arrow on the oven surface next to the knob but shifted over. So, for example, you can set the knob to 250 then paint an indicator next to the knob at 350. The drawback to this is that someone who is unfamiliar with your oven may be confused and could leave the oven on when they think they are turning it off. To solve that problem, paint a separate set of indicators on both the knob and the oven surface to positively indicate when the ofen is off.