scopes [was: how to troubleshoot? ...]

[J. Larry Hendry]

All this talk about multiple inputs on scopes got me thinking about
something I built to use with my scope way back in the 70s when I was still
in 'lectronics school.  It is a transistor checker.  It hooks to both vert
and horiz scope inputs and displays bent lines on the scope to define each
junction.  Base to emitter junctions display a line with two 90 degree bends
on opposite directions.  Connecting E to C or B to C gives a line with a
single 90 degree bend.  So, I dug it out of the junk, hooked it up to my
scope and yes, it still does the same thing it did.  I remember checking a
lot of transistors with this thing in the 70s when my supply for projects
was whatever I could get my hands on.

I have no idea where I got the plans or idea for the circuit.  Perhaps from
popular electronics or something.  It has a selector for in and out of
circuit testing.  There is not much to it.  it contains a AC 120 / 6.3 volt
transformer, a couple of resistors and switches, and that is it.  Anyone
remember such a "test" circuit or have any opinions about its usefulness.  I
remember it helped me sort a lot of transistors in to the "good" and "bad"
piles.  If nothing else, you can identify the leads on an unmarked
transistor.

Larry Hendry
(still trying to remember half of that stuff I learned back then)