Alan Douglas adouglasatgis.net wrote in message . ..
Hi,
Tim wrote:

My best guess, based on your feedback and some additional web surfing,
is that it may be a Model # 83YX142 or 83YX143. But I'm unable to find
any pictures or literature to confirm this assumption.

The 142 was portable; the 143 was a counter-top model without a
lid. They were renamed to "600" in the 1960 catalog. This 142/143
first appeared in 1955 and I expect you have an early one.

73, Alan

As a point of reference on the Knight 600 series, I was told by a
Triplett engineer (Bluffton, OH) in the early 1960's that the three
major kit companies Heath, Knight, and EICO received permission
approx. late 1953 or early 1954 (not sure of the date) to use the
circuit design from their early 3413, as Triplett was about ready to
release their model 3413A by then. The early 3413 was similar to
their previous (late) 2413 but with the U and C busses reversed, and
with an improved 626 panel meter, and other small improvements. As far
as I know, the early Triplett model 3413 predated any of the kit
models. The nice thing for us is that the Knight 600, Eico 625/628,
Heath TC/IT, and Triplett 3413/3413A/3413B data charts are
interchangeable, as long as one converts Heath letters to numbers and
be aware that some models have ten toggles, and some have twelve or
thirteen toggle switches on the three busses(be careful of the "cap"
switch assignment), and Heath eliminated the letter "I". Triplett
models 3413A&B had a redesigned circuit, but their charts were still
interchangeable with the 3413, by design. (3414 charts are different.)
Very late Knight 600 chart formats eliminated listing the plate,
suppressor, and screens as "Up", but retained the most significant
one, the control grid for the Up toggle; which also simplified their
Gas test, as one didn't have to look up the control grid in a tube
manual any more. These late Knight 600 charts also work on all of
these testers.

For those who own only a Triplett model 2413/3212; a simple
modification can be made so it can use all of these data charts, so
you don't have to buy another emission tester, just to test your
tubes. Install a miniature (~$4.50 at Radio Shack) DPDT toggle switch
as a buss reversal for the "U" and "C" busses, so it will function
either as a model 2413 or 3413. It's also a good idea to go through
the entire circuit to calibrate the (neon) short, Line Adjust, and the
four "A" ckt. (Eico "Selector") ranges, as the old carbon comp.
resistors, panel meter magnets, and solid (CuO, Se, Ge, etc.)
rectifiers often aged or failed, and some of the kits weren't
calibrated from the start.

Fred Scoles,