UNPLUG IT, then pull the back off, and look for any burned wires.

It's a 1967 Custom Imperial.  The model is RCIE-75L, (it's not RCIE-75-12) if that helps...

That's really a nice range! But the oven controls aren't the simplest on this model...  I have no experience with them as Canadian Frigidaire ranges from that period were very different and much simpler (but also less interesting!)...

If you ever want to sell it, and if by any chance you're in Portland Maine, I'd be VERY interested to get a range like that, even if it needs repairs! 

It COULD be the thermostat, but I think that is somewhat unlikely given the way this range operates.  It could also be a half dozen other things.  Like Phil said, the oven controls and their components for the right-hand oven on this range are VERY complicated.  There is not only the selector switch involved, there is also an 11-volt oven control circuit that involves a transformer, 2 thermal relays and a thermal sensor.  The thermostat for the right-hand oven is not your standard line voltage, capillary tube thermostat.  Instead it is part of the low-voltage control circuitry.  

The first thing I would check is make sure that the clock is set for "manual" oven operation.  Beyond that, there is not much else that can be done other than by going "in" with diagnostic equipment and searching out the problem.

If there really is a problem in that control circuitry, it's going to take a good service guy to tease it out and to try and find parts to repair it.  Another option would be to try and find a "regular" thermostat like the small oven uses and retrofit it into the large oven.  This would make the oven operate but you would lose all of the "high end" features (tendermatic, self-cleaning, meal-minder, and the automatic broil control).

As an aside, I will mention that my grandmother had the Custom Deluxe 2-oven version of this stove when I was a child.  She did 98% of her baking in the small oven.  The only time I remember the large oven being used was on holidays when she was cooking for 20+.

I've attached the electrical schematic for the large oven here so that other members can examine it.  Maybe someone else will have a suggestion for you.

And here's the circuitry for the small oven, for comparison purposes!

Actually, Phil the 1968 electri-clean ovens were quite different electrically from the 1967 models.  In 1968 all of the low voltage electronic oven control system was removed and replaced with a Helium-charged capillary tube thermostat for the self-cleaning ovens.  This thermostat controlled line voltage to the heating elements.  This eliminated the need for the 2 thermal relays as well as all of the complicated low-voltage resisters, anticipators and the thermistor. 

Also, the separate clean timer was removed altogether and the user would set the cleaning time using the Meal-Minder clock.

You are correct about the colors.  1968 saw the loss of turquoise in favor of avocado green.  Sunny Yellow was still available, AND some snazzy new colors appeared for the TOL 30" models: Matador Red, Nantucket Blue, Black Onyx and Spanish Gold!

That color experiment must not have been terribly popular because by 1969 your color choices were down the typical four of the period: Snowcrest White, Colonial Copper, Avocado & Harvest Gold.

Phil you are correct about exterior looks between the L & N lines.

I will take your word about the introduction of those "wilder" colors in 1966. It would seem that I am missing the 1966 K-Line tech talk. (Something to add to my "acquire list")

The 1966 laundry appliances tech-talks don't mention those colors, just the usual typical 1966 quartet of white, copper, yellow & turquoise, but since those "wilder" colors only appear on a few 30" ranges in 1967 I'm guessing that those colors would have only been additionally available on a select number of refrigerators and dishwashers as well. 

About colors, they were probably introduced later in the 1966 lineup as early Tech Talk documents (for kitchen appliances) don't talk about blue and red... 

But this is from the Spring K line (spring of 1966) refrigerator manual:

This ad also shows 1966 appliances in Matador Red. 

A FPI-16BK refrigerator and a RCDG-39K range.

John, you not only have Frigidaire's most beautiful range, you also have the matching most beautiful fridge that goes with it!  I'm a bit envious to say the least!

Here's a few pictures of the 1968 version. The most visible difference is the relocated lock latch. There's also one less indicator light for the Self-Cleaning function, the GM badge moved from the oven door to the lower left part of the control panel and different oven door handles.