The AM Forum

Hello, I replaced (2) 866 tubes with 3B28's with good success...one 3B28 had a very loose base but worked. I wanted to "check it out" so of course, Ooops...the tube slipped right out of the base.

Question-what is the trick to resolder the 2 leads back in?

Was thinking just add some solder to the 2 wires, slip back into the 2 appropriate pins and solder the outside of each pin. Is that the way to do it?

Any suggestions appreciated.
73
John-N2LK

Completely De-older the two base pins required for function (always check the base diagram first) before soldering in leads going into the glass envelope or bulb.  Or at least de-solder enough that you can see through the pins. This is traditionally done by hams with a baseball wrist-flick quickly after melting old solder in a ham's messy workshop with backstop cardboard or with a fast downward rap, etc.  ;D. If your experienced, fast and watch your lips and scatter area you can even blow out the melted solder.

I think the original base was cemented to the bulb with glyptol cement when original.
Just using an epoxy or gorilla, tm. glue should be ok if your choice can stand operating Temperature.  Be careful not to break the original bulb base seal extension in center of socket.

Then after glue is set, solder the leads making sure adequate solder is wicked up into proper pins.

Thank you, good info..

I know everyone has their favorite way to glue the base back on but I have found that superglue does the trick and can stand the heat generated by most tubes. Sometimes I find an old radio where all the bases are loose and before I attempt to remove them, I squirt a little superglue in there and wait 24 hours and then remove the tubes. As far as re-soldering the wires back on, I would use a little butane torch
on the pins about half way down to get a clean job. When using an iron, I have found that it usually leaves solder on the pins. That can usually be cleaned off with a small sharp knife. 

You may have to add a little fresh solder in the pins to get the old solder to melt.  Heat them up and quickly flick the base downward to get all the solder out.  You should be able to see light through the pins.  Make sure you use a high temperature glue.  Some epoxies will fall apart at high temps.  Re-solder the pins with tube upside down.  Don't use too much solder or it may run out of the pins inside the base.

Thanks guys