During or just after W.W. II there were Sinper-Scopes M1 and M3 that
were the near IR type and used a large IR filtered light source and
image converter tube. Typically mounted on the .30
carbine. Probably the carbine because the range was 70 yards
the M1. They used vibrator power supples and the tube ran at
about 4 kV.
This is a near IR (not heat type IR) viewer and source.
The source, MX-7987/PAS-6, is a two "D" cell flashlight with a
reflector and 1.6" diameter IR filter. The center off switch
momentary when pressed aginst the source and stary on when moved
from the source (ON)-OFF-ON. When you look directly into the
filter with the light on you can barley see any light. The
width of the source is very narrow when compared to the field of
of the SU-43. The range is greater than 150 feet, maybe more
100 yards (to be determined).
The IR viewer, SU-43/PAS-6, is made in a side by side tube
arrangement. One tube holds the BA-1312/U
(equivalent Radio Shack 23-901), High Voltage Power Supply and
ON-OFF switch and the other tube holds in target side optics, IR
converter tube and eye side optics. Both the target and eye
optics can be focused.
The ITT 6929 IR conversion tube has metal ring contacts at each end
make contact to the 12 kV supply. Inside the SU-43 housing
are metal fingers that contact both rings. The input end of
tube is mirror like and dome shaped, not flat so the objective
need to correct for that. The output is a flat screen.
I'm guessing the 12 kV power supply is a simple blocking oscillator driving a
Cockcroft-Walton high voltage generator (Wiki).
The back of the carry bag is fitted with a couple of ALICE clips.
The viewer has a groove that accepts the two pins on the source so
can be assembled into a single unit. Although there are two
to combine them only the way where both target ends point the same
When indoors in the daytime the switch can be turned on and then off
and it works for a number of minutes, but when outside on a sunny
the screen goes black after a few seconds after turning off the
switch. You can hear a faint whine when the switch is on and
SU-43 is next to your ear.
The knurled ring closest to the eyepiece (not the larger ring that
opens the body) allows focusing your eye (diopter correction) on
back of the imaging tube.
The knurled ring closest to the objective lens allows focusing on
distant or near subjects.
Metascope Battery Installation
Alkaline Radio Shack battery has the base and cylinder as the
terminal, like most othe Alkaline cells. The button contact is
the negative terminal.
Install the battery into the switch assembly with the button contact
up. I.e. the button contact (negative) touches the center
on the power supply module.
You may need to clean the top surface of the spring if it's rusty or
receiving the Radio Shack 23-9011 battery it was not clear from the
manual which way to put it in. Trying both ways resulted in no
Removing the power supply and using a lab power supply (HP E3617A)
was clear that the center contact on the power supply should be the
After seeing current (about 15 ma) drawn from the power supply it
placed into the SU-43 and the switch installed without the
battery. The scope worked fine for a number of minutes on the
charge in the power supply.
Used a 3/8" nut driver to remove the boot-switch nut.
Testing the switch assembly with the battery installed showed no
voltage. Checking just the switch with an Ohm meter (Fluke 87)
showed no continuity.
The switch is marked:
Spraying some Radio Shack Contact/Control Cleaner & Lubricant
(64-4315) into space between the toggle and the switch body and
the switch a number of times caused the feel of the switch to free
and the contacts and the SU-43 are working.
Operator's Manual for Metascope AN/PAS-6 (5855-790-9197), 17 April
TM 11-5855-239-23 ORGANIZATIONAL AND DS MAINTENANCE MANUAL INCLUDING
REPAIR PARTS AND SPECIAL TOOL LISTS METASCOPE
1936514 Discharge Tube, T.C. Lengnick, Nov 21 1933, 250/332 ;
250/214LA; 250/214.1; 250/333; 313/329; 313/524; 348/164; 367/7 -
oldest patent in 250/333
2131185 Electro Optical Device, M. Knoll (Telefunken), Sep 27 1938,
250/214VT ; 313/524; 315/10; 348/164; 348/832- IR amplification
2189321 Electro Optical Device, G.A. Morton , Feb 6 1940, 313/529 ;
250/333; 315/213 - visible light amplifier only?
2490740 Image Tube, F.H. Nicoll (RCA), Dec 6 1949 (filed Sep 6
1946), 313/526 ; 250/333; 250/368; 313/146; 313/249;
313/286; 348/164; 348/335; 445/14 -
Near IR Schmidt Optical System
2506018 Image Tube, L.E. Flory (RCA), May 2 1950 (filed Oct 5 1946),
- visible light only?
2692341 Electron-Optical Image Converter, P. Schagen (Hartforn
National Bank), Oct 19 1954, 250/214VT ; 313/541
Single accelerating voltage, not
multiple anodes, hemispherical input -
2739244 Infrared Sensitive Tube, E.E. Sheldon, Mar 20 1956,
250/214VT ; 250/330; 252/301.6R; 313/380 -
Instead of using an input optical
system like the prior art tubes this one has about 1,000 times
gain inside the tube.
2903596 Image Transducers, W.O. Reed, Sep 8 1959, 250/214VT ;
250/333 - longer than 1.2 micron IR
2994798 High Voltage Image Tube, G.L. Krieger (Army), Aug 1 1961
(filed Dec 26 1946), 313/529 ; 250/214VT; 252/301.6S -
Four accelerating anodes at up to 16
maybe M3 Sinper-Scope
3280356 Image Tube with Truncated Conical Anode and A plurality ,
Stoudenheimer (RCA), Oct 18 1966 (filed: Jul 17, 1958), 313/529
; 250/214VT; 313/107; 313/530 -
3376421 Quantum Counters, E. Snitzer (American Optical Co), Apr 2
1968, 250/333 ; 385/115 - fiber optic bundle
Hemispherical input at ground, one
other potential of 16 k, flat output window. very much like the
6929 tube in the PAS-6
2535708 X-Ray Generator
2666864 Image Intensifier Tube, R.L. Longini (Westinghouse), Jan
; 250/214VT; 313/107; 427/107; 427/109;
427/122; 427/124; 427/64; 427/74; 445/11; 445/12 -
Hemispherical input, but output is
a much smaller flat screen
2555545 Image Intensifier, Hunter (Westinghouse), Jun 1951
- designed for X-Rays
2686885 Insulated Coated Grid for Electron Discharge Devices,
Bailin (Sylvania) - tetrode power tube
2752519 Method and Apparatus for use in Chemical Evaporation
Process, Ruedy (Navy), -
method of making image converter
tube like the 2506018
2774002 Image Tube, D.R. Carlo (International Telephone and
Telegraph, aka ITT), Dec 11 1956, -
Hemispherical input, flat smaller
output, 2.3 kV& 16 kV to tube
2834889 Electronic Camera, Fries, May 13 1958, - image
amplification then to film
2839601Visualize Electric & Magnetic Fields
2851625 Image Tube, Ruedy (RCA), Sep 9 1958 - hemispherical input,
multiple anodes, 1,000 times gain
2857589 Adapter Device for Image Tubes, S.G. Fong (International
Telephone and Telegraph, aka ITT), Oct 21, 1958, -
Fits on front of tube and contains
voltage divider to provide 2.3 kV from 16 kV Sniper-Scope
2928969 Image Device, Schneeberger (Westinghouse), - maybe
for TV use
3415990 Invisible Light Sensor Tube and Faceplate Material (ITT), R.
Dec 10 1968, 250/338.1 ; 250/214VT; 250/330; 250/363.01;
250/367; 250/484.4; 313/103R -
uses UV light to be more sensitive
4037132 Image Tube Power Supply, A.W. Hoover, Jul 19, 1977, - for
microchannel plate Image Intensifiers
4041343 Electron Multiplier Mosaic Structrue, R.K. Orthuber (ITT),
Aug 9 1977, fiber optic micro channel plate - visible
Night Vision System, M. Wilder (Varian), Dec 26 1978, 250/214VT ;
250/333; 313/528; 313/534- micro channel plate
4173727 Electron Image Device, J. Vine (Westinghouse), Nov 6, 1979
(filed Jun 23, 1966), 313/529 ; 250/214VT; 313/537 -
“Fight at Night!”
U.S. Army Night Vision, 1945-1980 - various Sniper-Scope
versions and rifles as well as starlight scopes
FAS - Carbine,
Cal. .30, M1/M2/M3 -
Sarco - M3 Carbine
Sniper Scope Parts -
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