Check to see if your KNS80 has Mod 10 (should be stamped on the
back). I don't have the details, but this has to do with inter-
mittent contact between the internal circuit boards. Loose internal
contacts will produce the effects you mention. I found it cheaper
to buy a yellow tagged KNS80 on eBay than to fix my old one - but
it needed other repairs as well.

David Johnson