Our lower level oven does not heat up. The convection oven. A code of Fr shows. What Gives. The top oven is working fine. I have replaced the entire touch pad previously. We have a Jenn-air 30"Expressions Convection Wall Oven Model WW30430. Thanks Folks

The magnetron is the main part that gives out microwaves to heat the food. As the convection bit is working this points towards the microwave bits.
The magnetron has a main diode, fuse and transformer to run the microwave bit, any of these could be faulty. A word of warning though, there are extremely high voltages inside microwaves, even when unplugged in the main capacitor. Also to repair this section you will need to be a fully qualified engineer to even order parts for this.
Find a microwave technician who can repair for you

I just read that starting the microwave as usual and then slightly pressing in the handle (you can hear the heater(?) come on will make the heat come on. Tried it and it works. My repairman told me it needed a new magnetron ($700) but that was totally wrong. I will be trying another repairman to replace handle mechanism.

Hi,

Here is a tip that will help you to figure out what is wrong with your Microwave Oven....

Basic Microwave Oven Troubleshooting Tips

heatman101

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Hi,

Here is a tip that will help you to figure out what is wrong with your Microwave Oven....

Basic Microwave Oven Troubleshooting Tips

heatman101

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Hi,
Here is a tip that will help you to figure out what is wrong with your Microwave Oven....

Microwave Oven Basic Troubleshooting Tips
http://www.fixya.com/support/r5508031-microwave_oven_basic_troubleshooting

heatman101

Therer could be many causes for this and will need to be looked at by a qualified repair tecnician, I would suggest that you ask for a quote first as the repair could be simple of very expensive.

Hope this helps

Hi,
Here is a tip that will help you to figure out what is wrong with yourMicrowave Oven....

Microwave Oven Basic Troubleshooting Tips

heatman101

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Most likely the lower door interlock switch is bad. Cheap and pretty easy repair.

Martin Microwave Inc. sells the switches for around $5....

www.martinmicrowave.com

The door latch receiver has a spring action lever (inside) that is made out of plastic and cracks or wears through. You need to remove the cover and remove the two screws holding the door latch receiver. Now you can switch the top and bottom piviot switchs, putting the top one lower and the lower one on top..make sense? you"ll understand when you see it.

at highvoltage section wiring may bae problem, check wiring and connectrors of magnetron and capacitor and transformer.