[R-390] BEWARE of spray contact cleaners!

[WD9INP/4]

R-390A Crew,


I heard a long time ago that spray contact cleaner can be a no-no for cleaning some contacts.


Well, I learned the hard way that that is right!


The problem isn't in the cleaner itself, but in that it breaks up old deposits on the switch contacts and allows them to migrate about and create high resistance scales that insulate contacts one from another.


Try cleaning the contacts with acetone, remembering that acetone can also dissolve plastics.


Bakelite don't care 'bout no acetone so OK there, but the trimmers in the 2nd and 3rd I.F. cans DO care. They can open up. Fortunately, the can may be removed w/out removing the RF deck, but I don't know how to unbust a busted
trimmer.


Tears do damage, too. Wear goggles while crying!


73 de Charlie

Charles A Taylor, WD9INP/4
   Greenville, North Carolina