My question would now be (since you're assuming you'll have to drop a bunch of money on it anyway...) - what's the power out with it as it is, and how does it compare to how it was before you noticed the problem?
Jim's right about the resistance: at 15A or thereabouts per filament @ 5V, milliohms make a difference! Steve, W1ES/4 -----Original Message----- >From: Jim Shorney <jshor...@inebraska.com> >Sent: Jan 3, 2012 11:26 PM >To: "drakelist@zerobeat.net" <drakelist@zerobeat.net> >Subject: Re: [Drakelist] L4B oddity > > >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 >Drakelist@zerobeat.net >http://mailman.zerobeat.net/mailman/listinfo/drakelist _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
