Is it plugged in?Check to see if the circuit breaker is onIs it gas? if so is the gas valve open?Do the burners work?If you say yes to all above then you have a control problem or a bad heating element.
You seem to have the moxie and electronic test tools so why not try to get a schematic for unit? Appears to be your best bet. You can try a google search for it or try this site which often has electric schematics for appliances. Search Over 2 1 Million Appliance Parts
There should be a metal spring cip ring around the spindle of the knob which keeps it tight around the spindle on the switch. Sounds like its snapped. Compare it with one that works, they should just pull off and push back on, but with a little bit of resistance.
Conflicting information in the link. My best guess is 2010 Month 11.The only way to be sure is to phone them.EDIT to Add./ I just noticed you typed 'Whirpool', I have edited your post but am not able to edit my link. When it opens, add the 'L' and press Enter.https://www.google.com/search?q=How+old+is+Whirpool+Gas+Range..
I am a retired career chef, and had this one oven with choking CO in an airport catering kitchen. We had it serviced and it was fixed. It sounds like yours is not getting enough air mixed with the gas. Adjusting the gas is one thing but the venturi to the burners can partially block and unburned gas spills over. Remove the burner and venturi and boil it out in whatever you boil your fryers out with.
Are you on mains gas or propane because the jets are different.
https://www.google.com/search?q=commercial+oven+emitting+too+much+Carbon+Monoxide
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Here is text followed by a YouTube. Possible reasons why your oven won't turn on even though the gas and range hood are working:
Igniter: The igniter is responsible for lighting the gas in the oven. If it's faulty, the oven won't turn on. You can check if the igniter is working by looking for a glow when you turn on the oven. If there's no glow, it's likely that the igniter needs to be replaced.
Wires: The wires that connect the oven to the power source may have come loose or be damaged. Check the wires for any signs of damage or looseness and replace them if necessary.
Safety valve: The safety valve regulates the flow of gas to the oven. If it's faulty, the oven won't turn on. You'll need to hire a professional to repair or replace the safety valve.
Top 4 Reasons Oven Won't Turn On - Gas Range Troubleshooting (youtube.com)