My ge jvm3670sk06 keypad is shorted - GE JVM1850 1000 Watts Microwave Oven

I would not risk it. Your better finding out why there is a burn mark there. The plastic film with the burn mark will be a specific one for microwave ovens. Basic peel and stick plastics could be the wrong type and it could also melt when the microwave gets hot.

An F3 error code indicates that the keypad for the control panel is bad or has a short.

DONT work on a microwave unless you know what you are doing. Tthere is high voltage inside the cabinet that can kill you even if power is disconnected.

I found a good site to find parts for the microwave. It has the fuse for $7. GE WB27X10388 Line Fuse PartSelect
Here is another search form different sellers.
WB27X0007 GE Microwave Ceramic Fuse Replacement

The fuse info
Specifications:

• 250 Volt.
• 15 Amp.
• Type: Fast Blow.
• Approx. 1.25"L.

PCM/Smart board (comes with the keypad), If it is less that 30 days beyound the 12 month warranty call GE and ask for a "good will concession" ... 1800-GECARES

a shorted keypad is when the tiny capacitors across the keypad,become shorted,the only fix is to replace the membrane keypad........no fix

the membrane gets dirt under them and shorts out the keypad,you may as well just replace the control board which includes the display and keypad on the same board

Membrane keypads are not very durable, and do fail after a relatively short time.

The only method is to replace them as a spare part.

That's usually form shorted or shorting keypads.

What to look out for is is you get an F3 error on your keypad (assuming you have a GE - the code is different on other brands).

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

I always recommend that you spray non-ammonia cleaner on a soft cloth (not a paper towel which can scratch) and gently wipe the keypad.

And I always recommend that you use the vent fan when cooking on the stove top to keep heat, steam, and grease out of the controls.

Or just to be safe, you can just leave the oven's door open at night or actually any time you're not using the oven..

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

I report from owner manual.

F3 means : Short circuit on key panel (your touch pad).
You get F3 error if a shorted key panel is detected for more than 60 seconds.
Solution: . Replace key panel (touch pad).

Try first unpluggign power cord for five minutes.

If you think that the problem may had been caused by water inside the keypad you can try using an hairdryer on the keypad, taking care not to melt the keypad plastic.
If that does not work, then replace the keypad.

You can buy replacements here. or Order GE Microwave Ovens Parts Here