CFEB386JGS3 oven slow to come up to temperature

[cdods]

Hi,  hoping someone can point me in the right direction.

 

I've got a 20 year old Frigidaire CFEB386JGS3 wall oven, that has worked perfectly until last week.  It still appears to work perfectly, in convection mode.

In "bake" (non-convection) mode, it suddenly has started taking a very long time to come up to temperature.  (30-40 minutes to come up to 350F). Once up to temperature it seems to work fine.

No fault codes are displayed.

This oven uses the 318010701  control panel.

From the wiring diagram, any failure in the control circuits, would seem to prevent at least one of the elements from coming on at all.  But they definitely both come on.

Can anyone point me to what might cause this? 

Is it possible for a burner to fail such that it comes on, but isn't as hot as it should be?  If so, how would I confirm which burner has the problem?

I have tools to troubleshoot, but looking for pointers on where to start.  I'll have an unhappy family if I leave the oven disconnected for too long

 

Any help appreciated.  Thanks

 

[Vance R]

Check all the elements - newer ovens use all 3 element to do preheat. Ohms test to start with then move on to voltage test if needed.

[cdods]

10 hours ago, Vance R said:

Check all the elements - newer ovens use all 3 element to do preheat. Ohms test to start with then move on to voltage test if needed.

Thanks.  How do I know what resistance I should be seeing for a given element?  

[Vance R]

If you have the tech sheet or if parts list has the wattage. Watts = voltage X amps  so watts / voltage  = amps. using ohms law V= i/r - resistance is R= v/i. If you don't want to calculate most elements fail open or inifinite resistance.