Do you ever run with color on the plates? It's required that they get a little bit red in operation for the gettering to work.
Also, just a tiny bit of extra resistance in the filament pin is all it takes to dim a tube. An ordinary Ohmmeter won't register the difference. 73 -Jim On Tue, 3 Jan 2012 22:00:06 -0600, richard radke wrote: >All, > >Thanks to everyone who made suggestions. Solder on the pins all look >ok. .5½'s on each filament. I'm guessing a grid to filament short/ >leak when it gets hot. I did notice a slight bit of clouding near >the top of the envelope that wasn't there before. Maybe from running >the filament with way less than 5V. Thoughts ? At any rate, a >replacement 3-400Z is gonna be hard to find (out of production for >years) so I'll probably just get a new 3-500 to go with the one I >already have. > >Rick >W9WS > -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! "Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime." HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
