>I've noticed that one reason for melting solder on the filament pins in
>3-500 tube has been the corrosion of pins and or sockets making a very small
>narrow contact point where all the filament current must be drawn through.
>This heats up the contact to a solder meting point.
I have noticed that such problems are caused by a weak helper-spring on
contacts #1 and #5 on the 3-500Z tube socket. The solution is to
fabricate better helper springs or to use Kenwood 922 tube sockets.
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
FAQ on WWW: http://www.contesting.com/ampfaq.html
Administrative requests: amps-REQUEST@contesting.com