[Hallicrafters] Source for Switch

[William Evans]

I'm looking for the on/off switch which screws to the back of a  
rotary wafer switch.  This was used in a lot of Hallicrafters  
transmitters, but I can't find any new switches.  I have a beautiful,  
almost new-like SR-400 and the only problem is it sometimes turns on,  
and sometimes doesn't.  It would like to replace the switch to fi it  
and then everything would be perfect (or almost, anyway!)  anyone  
know of a source, or have an old one lying around?
Bill