Buttons on keypad not working

try this link might help you out.
magic chef microwave oven keypad wont work Google Search

can you say,,,buy a new one???

Keypad/keypads once faulty cant be fix . Buy a nex keypad

One of two things is happening, either you have broken connections in the membrane switches of the keypad and should replace the keypad(which is most likely) or your main control board has failed in a way that it can no longer read signals sent by the keypad.

SEE THIS CAUSES AND FIX IT. God bless you
Touchpad and Control Panel If the microwave buttons don't work the touchpad and control panel assembly are probably defective.

Touchpad If the microwave buttons don't work the touchpad might be at fault. Generally speaking, if the display is working and some of the buttons respond correctly but some don't, the problem is with the touchpad.
ser Control and Display Board If the microwave buttons don't work the main control board is most likely defective and will need to be replaced.

Main Control Board If the microwave buttons don't work the main control board is most likely defective and will need to be replaced.

Not always is in the keypad the problem,in my work the problem was in one of the connectors in the control board.Resolder the contacts and it'll be fine.

The microwave oven is showing a systems error, which means there is a short keypad membrane. The solution is to change the keypad to get it functioning.

Contact Westinghouse Small Kitchen Appliances at 800-245-0600 or 800-947-3745 or visit here.

Is it possible that some spray cleaner accidentally got into the controls?

Direct spraying of cleaners on the keypad and steam from the cooktop can damage the controls.

I always recommend that users spray the cleaner on a soft cloth (not on the keypad itself) then wipe the control panel off.

Also, I always recommend non-ammonia cleaners since ammonia can crack and damage plastic.

We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.

i believe majority of emerson got programmin ERROR intheir KEYPAD.. my emerson microwave got similar issue ..its a brand new one abt few monts old..it started actin weird way ..its keypad wont work..tried many thing unplug it pluge it back in everthing tht necessary..but still keypad is locked..no not the child procted locked..it locked with a digits 00.00 ...sometimes it work sometimes it dont...so no clue wat to do ...

i just brought my sunbeam microwave like two days ago. and it will not heat up