Just landed a EICO 147 Signal Tracer. This is the one piece of test gear I didn't have. This one uses a 1629 magic eye tube for it indicator. It is going to be fun hitting up an National NC-300 receiver I have. It does not come with it's probe I have a couple here that may work however the schematic for it's probe, and for other signal tracers are to be found at the site below. it is just a crystal diode and a resistor, I'll take one of the probes I have and rebuild it to suit.
http://www.ohio.edu/people/postr/bapix/SigTrac2.htm