Since forever it seems, my 1992 VC 2220 stove (top load stand alone) has had a rattle that comes, then goes. Fan activity affects it as it only ever rattles periodically if the stove is running. I've often stood there on the hearth applying pressure right, left, forwards, backwards, and sometimes it'll stop for a few minutes, until I get comfortable above in the loft watching TV, then it suddenly starts again. Stove top lid has a glass in it so I have never tried weight, but yesterday I sat a bag over the glass on a piece of plywood, and noisy rattle was gone. I tried it with half bag, same thing. I added some pieces under it so the section over the glass is near an inch above the glass, sat that half bag on, it's nice and quiet ever since. Today I added some screws. The plywood is a piece of 5/8" stuff I had, it'll easily support a full bag too. With the inch, if I scoot it back just a little, I can see into the hopper with a MAGlight. 
