What is the color of the sharp r-1480?

If your model is Sharp R-1480, see the service manual here.

You can order Sharp parts from Encompass here.

A short circuit diode will do that or shorted turns in the magnetron high voltage transformer, or the magnetron or a sticky/contaminated door switch.
Hope that helps.

Take this link to Sharp to view a pdf file of install instructions. The model number is different, but most install with the same methods.
http://www.sharpusa.com/CustomerSupport/ProductDownloads.aspx

check the door switches and magnetron

door spring may have broken,

We have the service / repair manual for this model and have uploaded it to our site here to help you.

It will give you safety info, step by step help in disassembly, troubleshooting tips, and even part numbers.

Most computers will open this document automatically, but you may need the free Adobe Reader.

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

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

Replace the magnetron and check the wave guide also.

The part you need is PDIFB026/KIT. Sears parts has it listed for $45.49 plus shipping, taxes, etc. (I get a lot of repair parts through them. They are very reasonable. It's also a good place to start when looking for a part. They have exploded views and parts listings for a lot of appliances. Then you can shop around once you have the part number you need.)

For your oven, here's the page:

http://www.searspartsdirect.com/partsdirect/getSubComp.pd?modelNumber=R-1480&productCategoryId=0123370&brandId=0958&modelName=MICROWAVE-OVEN&diagramPageId=00001&componentDescription=OVEN%20AND%20CABINET&documentId=P0101304&backToLink=Return%20to%20Sub%20Components%20list

You're looking for item 2-2 on the drawing.

You need to remove the grill above the door to find two more screws that go straight to the back wall plate. They will be on the left and right side. There are chrome or a gold color. That is the only other way that they mount to the wall.

Good Luck

The best place to order Sharp parts is Tritronics.

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