What is causing a horrible grinding noise when I Fast Forward or Rewind?

My VHS recorder make a horrible noise when I use fast forward or rewind. Could this be because the mechanism is dirty? If so, can I clean it? (These cleaning tapes don't seem to work.)
Sean Littlewood, October 2003


done
I had this. In the mechanism, the old grease/graphite had congealed over the years. I dismantled many cogs etc and cleaned them. Problem was a cog could not move properly. It takes a lot of patience. When dismantling, do drawings and put the disassemblies in seperate little pots. Mine Mitsubishi M1000 is great now!

John Davies, June 2004