After a power outage, microwave clock runs crazy fast, and the timer is also too fast.

REturn it

Sounds like the microwave thinks it is running at 50Hz. They sense this automatically. most of the time a reboot will fix it. worst case, replace the control board.

You have the unit in demo mode, Follow instructions in manual to exit demo.

This is often just a bad connection on the bottom of the noise filter board. Look for burns and ring cracks. See the attached photos. For disassembly info, you can watch the video at my site, or see these text files: http://www.microwavecontrol.com/safety.htm
http://www.microwavecontrol.com/disassembly.htm If that doesn't fix it, it may be that the bottom door switch is bad, or its mount is loose, misaligned, or broken. See my help file on door switches here.
Also see the Fast-Track manual for model SMH1611 here.
Feel free to contact me directly (see below) if you have other questions.
.- William E. Miller, AS-EET
[email protected]
http://www.MicrowaveControl.com
Microwave Oven Control Panel Repair Nationwide
"Recycling by repairing since 1982"

this a problem with the clock , but the microcontroller can be defective by the power outage, see the diagram . how the microncontroller has the control for any equipment.
IN SHTE M.CONTROL BOARD CAN BE DEFECTIVE. go to the repair shop Tv FOR FIX IT. God bless you

No... you are not in a microwave induced time warp...
Your microwave oven needs a "reboot". The same thing happened to me.
Unplug your microwave oven, wait about a minute (more or less), plug it back in. Try setting/running your kitchen timer, boil water, etc. Your timer software on the microwave should be reset.

I've just fixed a very similar problem with a 10-yr-old NEC microwave oven.

Disconnect AC power, take the top cover off, go through the unit and tighten all screws, particularly those connecting ground wires to the chassis and those fixing major components like the power transformer and magnetron to the chassis.

The first thing to try is a "hard reset". Unplug it from the power line for a minute, plug it back in, set the clock, then try again.

Let us know if the hard reset doesn't fix it.

Pressing "timer/clock" button 4 times turns on and off demo mode.

It sounds as though you may have run the microwave while empty, which can damage the magnetron.

Not that I'm optimistic, but the first thing to try is a "hard reset". Unplug it from the power line for a few minutes, plug it back in, set the clock, then try again.

Let us know if the hard reset doesn't fix it.

Otherwise it likely needs a new magnetron.