You say "dead short"? That would zero or virtually zero ohms.
The normal reading at the power cord would be anywhere from about 80 to 250 ohms on that oven.
If it is zero, I would suspect the varistor has shorted due to a surge.
Viking microwave ovens are made by Sharp and the VMOR205 is essentially a rebranded Sharp R-1874.
The service manual for the R-1874 will be helpful and it's located at our site
here.
Feel free to contact me directly (and
please include your full model number from the tag in or on the
unit) for more help or to get a varistor.
William E. Miller[email protected]http://www.microwavedisplay.comWe're
happy to help you with free advice and we'd appreciate your thoughtful
rating of our answer.