Double Oven will not hold temperature; heats intermittently

Oven/Range/Cooktop Repair
1

Brand: Jenn-Air
**Model Number:**JDRP548WP02
Main Symptom: heats intermittently, does not maintain temperature
What happens & when:

I have 48 inch range/oven. it’s a re-badged kitchen-aid of the same type.

both ovens do the same thing.
steps:

  • set to bake 350
  • oven reaches 350 (verified with manual temp gauge too)
  • wait 20-30 minutes, and temp drops to 290-320, or whatever, something low… but display still says 350.
  • press cancel, then restart bake at 350, then display updates to actual temp, and heats back up.
  • so if i want to bake for an hour, I can, I constantly have to keep resetting the oven temp.

Both ovens do this.

Checked both temp sensors, reading 1080 and 1085 ohms. all good.

no error codes exist when i go to diagnostics mode.

So, this oven has 2x control boards, identical, one for each oven.
I also measure separate power board (aka switch mode power supply, SMPS), and its outputting 120vAC, and 14 vDC just fine.
I assume temp sensor and element are fine, if I can reset the bake, and seems to work.

SO, possible issues:

  • Both failed control boards? (seems unlikely, but possible)
  • failed power board? (measurements match, but could it have some intermittent issue, or voltage drop issue I’m not able to detect? this would affect both oven control boards)
  • wiring issue? (not sure what to look for)
  • Other?

Thanks in advance.

Error Code (if any): none
Parts or tests already tried: no parts yet, did test above.
Photos / video link: none

2

It sounds like there is a logic failure in the programming. It is possible that the machine interface logic control could be the cause of failure. However, if you inspect the controls, do any of them look like they might have a charred spot? Has there been any fluids that may have boiled over onto the console? WPW10464534 Keypad Assembly (Oven Control) | Genuine Whirlpool OEM In Stock

3

Thanks William.

So, just to make sure we are using same names of boards, and to note, this 48in oven range is setup a bit different than some traditional oven repairs i’ve seen.

  1. This has a touchscreen (HMI Interface). this appears to have no “controls”. seems to have a serial communication line to the main “Oven Control Boards” (this is the logic boards). this is mounted in the front panel between the gas range knobs.

  2. SMPS, which is a power board. seems like a “dumb” board that distributes power, 14VDC to the touchscreen/HMI INterface and to the “Oven Control boards this is mounted in the front panel, next to gas knobs too.

  3. It has 2 Oven Control boards (logic boards). each oven has its own board, same part number. these are mounted under the oven, with slide outs to access them. I doubt any water could get down here.

I attached the tech sheet here too.

Thanks again for feedback. Hope to hear ideas from others.

JDRP548WP Service Manual Range Oven Jenn-Air TechSheet-W10403303-RevA.pdf (1.5 MB)

4

Since this is happening with both ovens, the human machine interface is a possible cause of failure. It has its own logic which, when replaced, requires that it has the model number programmed on initial installation. Are there any evident signs of damage to any of the controls, to include the human machine interface.