Thermostatic switch fo 30 year old tricity marquis double oven the oven heats up but the temperature control does not work.

It was common for the broil element to come on during the preheat time on older oven controls. When the oven reaches temperature the broil should shut off. If this just started then the points in the broil switch section are welded together and the oven thermostat will need replacing

Hi Les. We had a tower oven with three ovens! One oven we constantly used had the element distort, and it had to be replaced.
Most likely the element is on its way out. If you have a multimeter, you can check the voltage supplying the element.
You will need to find the make, model number, and maybe the serial number of the oven to progress.
The details may be inside the oven door or on the rear of the oven. Do a google search, and you should be able to find replacement elements, and a local supplier of original parts or aftermarket replacements.

it has to be the temperature control itself...thats the only other component, aside from the high-heat cut out switch which rarely goes bad.

Possibly a faulty element or maybe just an open circuit temperature switch, that's assuming the thermostat is ok.
You need a multimeter to start checking the continuity of the above.
An element will be something like 15 to 30 ohms, a temperature cutout switch located on the oven housing should have zero ohms across the contacts (when cold)
Hope this helps

I have had a similar problem in that the top oven was overheating getting hotter and hotter and have just got a replacement thermostat from Partmaster.co.uk. This is to fit a Tricity Bendix from Currys model number DSIE520 GR. The new one seems just like yours in that it has three lettered connectors A,B and C. With the part came a sheet stating that for a free standing appliance with NO timer (this what my cooker is) the connections to be made are : 2 on old part to A on new; F on old to B on new; G/H on old to C on new and the link from G/H and 6 on old to be removed or "severed". I haven't yet done this as its in my cottage which I'm going to this weekend. Good luck! James

you need to have a new thermostat fitted or the old one re callibrated if possible

I do not know.

Thermador SCD302 upper oven preheat does not work; the heat temperature goes up very slow.

my ge profile double electric oven, bottome convection wont heat up

We have the same problem with our oven, AEG B2190-1.It started on on Christmas day[worst day of year]gets up to temperature after 10-15 minutes cuts out everything switches off until the oven has cooled down, The oven is only 18 months old. We have been told that it is a thermostat problem.