Sharp 1874- Door seems to "jar open" and oven stops

Your connection is bad. Start with a good and complete cleaning of the product. UNPLUG FIRST. Sometimes in the hinges things gum it up. DO NOT STICK anything into the door latch area.
If this continues, you have an issue that must be decided if you should REPLACE or repair. Repair will cost more than replacing. Sorry.

I would say the mount for your bottom or top door switch is loose, misaligned, or broken. And you may have a failed door as well. See my help file on door switches here.

Slamming the door and opening the door while it's cooking instead of hitting the "Stop" pad before opening it both contribute to door switch trouble.

The service manuals covering this model are here and here.

You can order Sharp parts from Encompass here or you can call them toll-free at 866-779-5835.

That would be just a defective secondary interlock (bottom door switch) or its mount.

My help file on door switches is here.

The service manuals you need are here and here.

You can get other Sharp parts from Encompass here or you can call them toll-free at 866-779-5835.

I have exactly the same problem; always after 59 secs, it stops.

change damper motor and switch. cost is approx $30.00. unit must have cover removed to gain access to motor & switch
Bob

That switch is supposed to tell the computer if the damper door is open or closed. If it does not go to zero ohms, the CPU doesn't know what to do. Check the thermistor too...... just in case...

buy a new one they are not expensive wal-mart has 1000w for about 80 bucks

Fixed the problem without any help from anyone. If you ask and ask and get no help I guess it is time to take on the problem and see if you can resolve it and I did. NO IT WAS NOT EASY but with a little thought and time over the last 2 days I did get the door changed. Thanks for letting me post even though I got NO help.

We have the service manual, and have uploaded it to our site here. It is only a supplemental type, so it does not show disassembly, but it has helpful info and part numbers

We have a handy disassembly video at http://www.microwavedisplay.com

This is a problem in one of the damper-related components, most likely the switch, but it may also be the motor or the damper door.

The damper is a door inside that opens or closes depending on cooking mode. If the controller senses that the door is not in the right position, it will shut down the cook cycle.

Sharp models stop after 59 seconds.

See the attached sample photo for a typical damper assembly.

The best place to order Sharp parts is Tritronics.

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

That would be a problem in the damper aseembly, either a bad switch or motor, or the damper door is jammed or blocked.

Consult the attached diagram for general reference.

The damper switch is the same as the primary interlock (door) switch.

If you or a friend decide to look into it, we have critical safety information, switches diagnosis and replacement, and disassembly information at our site, linked here on Fixya: http://tinyurl.com/yzjozk