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Can you get us the model number ?
Item #756849 (OEM Part)
Clock retrofit replacement; w305b (black)
Manufacturer Number 86600B
This part has been permanently discontinued by the manufacturer and we don't know of any source for the part
but I have found if you search enough on the Internet sometimes you can locate these some supplies still have them in stock but I'm not sure where so you will need some research done to locate one, if that doesn't work and you can't find one in your only other choice would be replace the oven or here's a link to a place that rebuilds these you can call them and see what they can do for you, http://www.appliancetimers.com/ I hope this helps, thanks, Bryan