According to Andrew VK3BFA :
Joseph Gwinn wrote:
In article .com,
"Andrew VK3BFA" wrote:
http://www.jaycar.com.au/products_uploaded/SL2692.pdf
is a link to the typical tube I was talking about.
[ ... ]
what you see is what you get - the data sheet was all that was on a
local retailers website. probably, asuming your in the US, that Digikey
or Mouser would have similar ones - perhaps they would have more data.
The max strobe rate - no idea, but I cant imagine that the listed tube
in the original post is the ONLY one suitable in the world.
There is also the FX-7 -- which appears to have a larger
envelope size, but otherwise be similar, so it might work, except for
not fitting the reflector. And I'll bet that it is at least as
expensive as the FX-6A.
Its a basis for experimentation - might work, might not, Relatively
cheap and easy to lash up - if it works, a nice bit of test gear back
on the road, if it doesnt - well, youve blown 10 bucks and a bit of
time..... Trigger transformers are also available, about 2 dollars.
Yes -- but these are quite unlike the FX-6A.
The FX-6A is in a stubby 9-pin miniature tube base.
It has the two main electrodes allocated to two of those pins.
It has *five* *internal* trigger electrodes connected to five of
the remaining pins -- fine wires reaching in to points along the arc
path, and all electrically independent.
The Strobotac has a 7-conductor ribbon cable going from the
electronics box to the pivoted stem which contains the 9-pin socket for
the flash tube, and over which the neck of the reflector fits. (This
rather limits the maximum dimensions of the tube to ones no larger in
some dimension than the diameter of a 9-pin miniature tube.
The reflector is designed so the arc length (about 1/2" long) is
in the focus of the reflector.
The internal flash triggers operate (presumably) at a much lower
voltage than external triggers.
The fact that a separate wire is brought out to each suggests
that each has a unique voltage applied to direct the arc along the
intended path.
I am a working technicain, not an engineer - cant give you voluminous
theory on the application, I use the "suck it and see"
approach........sometimes works, sometimes a spectacular failure.
Including possibly an induced failure to the trigger circuits in
the StroboTac in this case.
While I have the four remaining unused lamps, plus the one in
pretty good condition, and one rather darkened from use, I intend to use
it as it was designed.
If those ever are all expended -- *then* I will try retrofitting
some newer flashlamp. But I think that not too many of those are
designed to survive 27K flashes/minute. :-) And I'm not sure about the
trigger transformer, either.
O.K. You finally got my interest piqued sufficiently, so I just
pulled it out of its case:
1) It is old enough to be tube driven, not solid state. A 5965
and a 5727. This suggests that the trigger circuit is not as
fragile as I at first feared.
2) Looking at the ribbon cable end inside the box, the flashlamp
main terminals are the end-most ribbon cable leads, the only
trigger connection is for the center one, feeding the centermost
trigger electrode which suggests that the ribbon cable acts as a
capacitive voltage divider to couple signal to the remaining
trigger electrodes.
3) The trigger transformer is a potted brick, about
1-1/2 x 2-1/4 x 3/4"
4) The main capacitor for the highest flash level is 1.15 uF at
1000 VDC. The smallest is 0.47 uF, also at 1000 VDC. The
middle one is 0.22 uF, again at 1000 VDC. They are all marked
"Vicofilm Capacitor" from "Industrial Condenser Company".
5) It does have *some* solid state devices -- a bridge of top-hat
rectifiers. :-)
6) There is also a three-section electrolytic. 50 uF, 25 uF, and
25 uF at 450VDC.
7) The speed pot is one of General Radio's special precision wirewound
pots, though there are four Allen-Bradley sealed pots scattered
around the rest of the circuit.
8) And, of course, it has a custom power transformer, with no
useful markings.
9) Two slow-blow (MDL) fuses (1/2 A, 250V) in clips on one of the
circuit boards.
10) One NE-2 lamp between two upright braces, secured by a
heat-shrink band as a vibration seal. It is presumably a
voltage reference, as there is no way for the light to get out,
and the pilot light for the speed scales is a bayonet-base
incandescent pilot light. (Another NE-2 is used as part of the
calibration system -- it is visible through a window in the
front panel, and you set the speed pot to specific speeds, and
tune the front-accesible pots for lowest brighten/dim rate in
the lamp.
11) The date codes on components seem to be in the 1967-1968 range.
Don't expect me to attempt to trace the circuit -- it is General
Radio's quality construction of the period, with single-sided circuit
boards, but it is too dense a construction for me to bother without
serious need.
But I
do get enough oddball electronic things like this working to make a
(precarious) living.......the high value or rare device thats worth
putting a few hours of experimentation into before they go to the
dumpster....
Understood. But at present, it is cheaper to buy more
StroboTacs on eBay than to buy new lamps. So -- as long as the lamps
with those are in good shape, you could get one, sell the lamp back on
eBay, and experiment with your own StroboTac.
FWIW -- the energy per flash is in three ranges, corresponding
to three flash rate ranges, so you don't overheat the lamp and burn it
out too rapidly.
Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. |
http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---