CANNOT FIGURE OUT HOW TO CALIBRATE THE OVEN. OVEN TEMPERATURE IS OFF 50 DEGREES. INSTALLED A NEW THERMACOUPLE. THIS DID NOT HELP THE PEOBLEM. OVEN WAS PURCHASED IN 1992. THANK YOU FOR YOUR HELP.

Jenn Air Recalibration.

How to Calibrate the Oven - Product Help - JennAir

https://producthelp.jennair.com > Product_Info > How_...
Aug 1, 2022 - Toggle through the settings and select either temperature calibration or oven calibration (depending on model).
Missing: JJW9630 ‎' Must include: JJW9630

How to Calibrate the Oven - Too Hot - Electric Range - JennAir

https://producthelp.jennair.com > ... > Too Hot
Apr 27, 2021 - The oven temperature can be calibrated to fit your needs. If you have determined your oven needs to be calibrated, below are the most common ...
‎Possible Solutions · ‎How to Calibrate or Adjust... · ‎New Oven and Too Cold

Question edited for clarity.
Question moved to Thermador.

This says the adjustment is behind the control knob.

https://www.justanswer.com/appliance/1o2k7-calibrate-thermador-oven.html

Videos here. You may need a new thermostat.

https://www.google.com/search?q=Thermador+PRG305PH%2F02+calibrate+oven+temperature

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Generally the oven temperature will fluctuate as much as 30 degrees above or below the set temperature. The longer the oven is on, the less the temperature fluctuates. If you measure the highest and lowest temperatures readings with a thermometer after the oven has been preheated at least 20 minutes, you should come up with an average temperature somewhere within about 10 degrees of the set temperature. You can calibrate most ovens up to 35 degrees higher or lower if it is off. Any more than that requires replacing parts.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/jeffrey_634abadf963e31e5

If the knob is consistently 25 degrees off from the indicated temperature the simplest and cheapest fix is to make a new indicator mark on the stove 25 degrees from the original.or some knobs have a glued on ring with the temperature numbers on them . Removing the ring and regluing it at the correct position could also work. Hope this helps.

Sounds like you need a new oven thermostat or get an oven thermometer and by experimentation draw up a new heating range for the oven dial.

You can only calibrate the temps about 20 degrees. If it isn't getting close to the temp you set it for, you probably have a faulty oven sensor and need to replace it. They usually run around $50-$90, and are easy to replace.

There is a faulty thermocouple(temp sensor) or the microprocessor is glitching/malfunctioning. You should have a certified tech fix this but, if you want to do it yourself, I can help. This is more involved than the length of FixYa's solutions can take. Find me on HowardForums.com as MeccaTronix and we will go from there.

There is no real way to calibrate the thermostat. Most ovens have the same problem. By lowering the setting slightly will help get a closer temperature. Sometimes similar thermostats are substituted and may not be exactly the same as the original that came with your oven. Hope my trying to answer your question was helpful, Thanks, Sea breeze

Temp probe/thermometer inside oven dirty, or off attachment, or defective. On some models, a small screw head adjustment is provided to calibrate thermometer under dial knob. Else, I would just set dial 50 degrees higher rather than expense of new thermometer or dial.

It's on page 32 of the manual for Thermador's built in convection ovens. 1. turn off the oven 2.touch and hold the start pad and then touch the bake pad 3. 0 (zero) appears in the temp digits. release all pads 4. touch bake and 0 changes in increments. max adjustment is 35 degrees F. 5. to complete change touch start for lower oven on double ovens do this: touch the roast pad instead of the bake pad continue with steps 3-5.