Tube Tester with Test for Microphonics

Dale- On the Eico tracer you can jumper the RF input lead to the regular input. This gives you- or at least it worked for me- the ability to be able to directly hear the signal off a tape head.
 I also put in diodes instead of the rectifier tube, and a dropping resistor. Yeah, even after a total recap it still has some hum.
 I am thinking of rewiring mine with all shielded wire and maybe grounding all to a common point.

That rewinds me - I picked up another Radio Shack/Micronta 22-010 Transistorized Signal Tracer at the Stanardsville (Greene Co.), VA hamfest a few weeks ago. For more than 40 years I have used one of those RS tracers in the field. The EICO 145 in the shop looks nice, but I have never been able to get the hum low enough to satisfy me. The EICO will be retired and replaced by the RS, freeing up much needed shelf space for my EICO 950B Resistor-Capacitor Bridge. I need to make a dual-banana-plug to tip plug cable to connect the RS tracer to the microphonics jacks on my Hickok 533 (a very useful function). Yesterday I finished rebuilding and reorganizing the pegboard in the shop with the addition of longer pegboard hooks so I now have room to hang additional test leads.

Looking at some of my older tube testers ( 1940's or 50's?)  I noticed a test feature that is sorely missing from the newer testers.

 The tester, a Sylvania model 123, has a pair of tip jacks on the front panel which say "Phones".

 You plugged in a pair of headphones and tapped the tube under test. If it was microphonic you would hear a "ringing" sound in the headphones.

Quite useful for testing tubes in amps and TV tuners.

 So if you see this on a tube tester, now you know what it was for.