Shaft that connects oven control knob has sheared so cant turn oven on

Get some epoxy putty, grease the shaft with Vaseline, put a small pea size piece of epoxy rolled thinly and insert it into the knob where the flat part registers on the knob. Push the knob into place and leave it 24 hours to cure.

I use this.

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parts need to have the model number sometimes the part with have the number etched on to it

You didn't say whether you have a gas or electric oven, or oven & stove. I'll assume you have a stove, just to cover all bases.

First, you should shut down the oven: a gas stove will have a valve on the gas line behind the stove. The valve will either have a red handle or a flat stem that usually has a hole in it. Turn either valve 1/4 turn to shut off gas, use a wrench on the flat stem. An electric stove should be shut off by flipping off the double circuit breaker for it in your electric panel. Do not unplug an electric stove when it is on; this can damage the plug &/or electrocute you.

Most likely the inside of the knob has stripped out. Look at the knob for a hole that has a setscrew in it: a small allen wrench or screwdriver will loosen the setscrew, most knobs don't have them and will pull off. Be careful to use even pressure on two sides of the knob; if you can't pull it off, use two butter knives or flat screw drivers to pry it up enough to get a grip on it.

Look at the center stem on the back of the knob, it will likely be cracked or stripped. Some stems have a D-shaped metal insert that strips out inside the plastic stem. If you have one, pull off a burner knob and compare the stems in the back, if they are the same size, put the burner knob on the shaft for the oven control, and use that knob to turn the oven control off.

If the burner knob won't fit, use your fingers or a pair of pliers (gently) to turn off the oven control shaft. If the shaft stops normally, you can turn the stove back on using either the gas valve or the circuit breaker. If you have a gas stove that doesn't have electric ignition (a clicking noise when you turn on a burner) you may need to re-light the pilots for the burners. Lift the covers off the burners to re-light the pilots.

If you have succeeded in turning off the oven, you need a new knob -- you can get one at an appliance parts store or maybe a hardware store. If the oven control did not turn off normally, I would leave the oven/stove turned off: the control itself will need to be replaced by a qualified repair person.

You need to change the "Simmerstat", take the model number to your local electrical parts supplier/parts counter at your local stove retail shop that sells Simpson stoves and ask for one for that model, make sure you get the right one for the position as some control a single element and some control dual elements.

*** TURN OFF THE WALL SWITCH AND ENSURE NO POWER IS APPLIED TO THE STOVE BEFORE PROCEEDING ****
Remove the upper back panel of the stove. Swap wire for wire of the old simmerstat to the new one, remove the knob from the old Simmerstat, undo the nut securing the simmerstat in the oven control panel and discard, fit new one, secure, fit knob, fit back panel, turn on wall switch and test.

Some countrys/states require registered electricians perform this task on electrical appliances so you must ensure you can do this legally before you start and take the relevant safety precautions and don't electrocute yourself.

first pull the knob off the shaft and check to see if its broken where the shaft is supposed to lock-in if so u jus need a new knob. if not you have to pull the panel off the stove and replace the shaft this shouldnt be too difficult either way.

I can only speak for the 720. If you want a circuit/wiring diagram for this one, then I need an email address. I will then register this on my BT Digital Vault and you can the download the whole manual.
Looking at the diagrams, the neon for the main oven has white and black wires.
The white wire from the main oven neon goes onto the same connector on the thermostat block as the white wire to the oven element. The black wire from the neon goes to a common terminal on the top oven neon, which then goes onto P6 of the top oven switch (still black wire).
If you need any more info, then let me know.

I have the same model stove for sale. here is my number 678-644-2161 samantha

First contact GE directly, they will send you replacements for half that price and you can do the labor yourself. 1-877-959-8688

The oven control panel has failed. For more tech help with this issue and a place to order parts I suggest you go the link below, it is where I go for parts and help. You will need to model number available. Appliance Parts Lawn Mower Parts Heating Cooling Parts 365 day returns

it sounds like it burnt one of your main wires in the back of range. by turning a knob on you are getting a feed back. turn the power off remove back panel take a visual check of your wiring.