TVS-2B Night Vision Scope MX-7794B

Crew Served Weapon Night Sight

Brooke Clarke 2005 - 2008

TVS-2 with AC
          adapter & transit case
What Goes Wrong
    1100BA Battery Adapter
    Battery Eliminator


This is a Vietnam era Crew Served Weapon Night Vision Device.  It uses a Schmidt-Cassegrain optical system.  The manual says 7 power.  The objective diameter is probably 5.5 to 6 inches.

Image Intensifier

Marked: Image Intensifier, Type: MX-7854/UV, FSN 5855-051-2702, U.S. Property, Ser. No. 17452, 8524
2.74" diameter x 7.3" long.  34mm flat exit diameter.  1.4" dia. flat fiber optic plate.


Marked: Oscillator H.V., M?052374B(F10), Lectrospace Co., Westbury, N.Y., Contract No., DAARC7-69-C-032, Ser. No., 3922
The oscillator has a socket on it's bottom that plugs directly into a pin on the image intensifier.


Turning the Focus knob clockwise moves the main mirror back

Lens Cap - Filter

The front cover contains a small open segment and a filter wheel with 3 neutral density filters, each more dense than the prior one as well as an open window.  This would allow testing the scope in the daytime.  Using the darkest filter on a cloudy day is about the same as no cover at night with 1/2 moon on distant hills.


This sight is intended for use on either the M2 .50 cal. Machine Gun (M2 rtucule) or the 106 mm Recoilless Rifle (M40 reticule).
This on is setup with the M2 reticule and straight through eyepiece.  When the M40 reticule is used the right angle eyepiece is  used.
The reticule gets it's electricity from a cble that goes into the front of the front lens element.  This is not a high voltage wire.


The switch with the pointer has 3 positions.  CCW is OFF, then scope ON, then Scope and Reticule ON.
The large knob controls objective focus and the eyepiece controls focusing on the image intensifier tube output window.
When looking up at the stars at night there's a much larger number of start visible than with the naked eye.  Also there is no night adaptation of the eye needed since the scope has a bright output.  But you probably can see fainter stars with night adapted eyes.  The output color is green to match the peak in a human eye's spectral response.

This scope was not intended to be hand held, and doing so is very difficult.  Need to figure out a way to get it mounted on a tripod.

What Goes Wrong

Upon receipt the unit appeared to be DOA.  The 1" diameter knob on the top of the scope gives access to the oscillator, which can simply be lifted out.  Plugging it in and removing it a few times cleaned it's contacts and now it's working OK.  It again failed to start and cycling the oscillator up and down a couple of times fixed it.  Maybe it needs cleaning with a pencil eraser?


BA-1100 Battery

Home Made
            BA-1100The original battery was the BA-1100/U 6135-00-926-0827 which is one of the long obsolete Mercury based batteries.  A prior owner has made a simple battery adapter by taking a four "AA" battery holder where all the cells are wired in series and attaching a metal plate to each end.  The "battery" goes into the scope Positive (+) end first.  The scope case is a negative ground.

The 4 AA battery holder has both the + and - terminals on the same end.  This adapter is made by placing a metal plate on the terminal end with the positive contact connected to the positive terminal and with epoxy or hot melt glue insulating the negative contact.  A diode is connected from the negative spring to the opposite end and goes through a small drilled hole to the negative metal plate that is glued to insulate it from the jumper eyelets on that end.  Single sided PCB material would be a good material to use for this.

The BA-1100 used 4 Mercury cells which when fresh put out 4 * 1.35 = 5.40 Volts.  When dead it was 5.0 volts.
If 4 AA rechargeable batteries were to be tried they would be about 1.4 V * 4 = 5.6 Volts fresh and 1.2 * 4 or 4.8 when dead.  So although they probably would work when fresh, the useful life would be short.
If 4 AA Alkaline cells are used the fresh voltage would be 4 * 1.52 or 6.08 which is a little too hot, that's why the diode is in the adapter to drop the fresh voltage down to about 5.6, very close to the Mercury battery.  The 5.0 volt dead voltage for the adapter occurs when the cell voltage is 1.4 so when the AA cells no longer work in this adapter they would still power a flashlight.

1100BA Battery Adapter

1100BA Battery Adapter
          replaces BA-100/U
After working with the Battery Eliminator (see below) it's clear that 6.6 Volts DC is OK so the diode used in the above battery adapter is really not needed and not desired since it wasts energy.  The 1100BA product does not use a diode.

The brass disk contacts have polarity (+) and (-) stamped into them.  Also the label "TVS2 cap Positive" is on the Positive end.

Battery Eliminator

This is a battery eliminator that replaces the BA-1100/U Mercury battery that's long obsolete.  It's line powered from regular 115 VAC single phase power.
                  Battery Eliminator
                  Battery Eliminator
                  Battery Eliminator
Power Converter for Night Vision Sights
Input: 115 VAC single phase 60 Hz
Output: 6.8 VDC
shown with pin A next to wide keyway
at top. Letters go clockwise.
DC output is case threads
and spring.

The A.C. cable will use a MS3116E-14-5S or MS3116F-14-5S or MS3116P-14-5S connector.  
The MS3116E-14-5S is the lowest cost and is available from William Perry Co.
Wiring is A.C. line to pins B and C.
Earth ground to pin E = threads on battery eliminator and connector shell.
Open circuit output about 6.6 Volts.
Although only three Night Vision Sights are listed on the batery eliminator it should work for anything that uses the BA-1100/U like the TVS-2B.
These are available from Mike Murphy on his NIGHT VISION, SURVEILLANCE   AND RELATED ITEMS web page.


TM 11-5855-202-10 If you have a pdf let me know
TM 11-5855-202-23P Organizational and Direct Support Maintenance Repair and Special Tools Lists (Including Depot Maintenance Repair Parts and Special Tools) For Night Vision Sight, Crew Served Weapons AN/TVS-2 (NSN 5855-00-087-3144), AN/TVS-2A (NSN 5855-00-791-3358) and AN/TVS-2B (NSN 5855-00-484-8638)

TM 11-5855-203-10
Night Vision Sight, Individual Crew Served Weapon AN/PVS-2 (NSN 5855-00-087-2947), AN/PVS-2A (5855-00-179-3708) and AN/PVS-2B (5855-00-760-3869)

TM 11-5855-203-13 Organizational and DS Maintennance Manual, Night Vision Sight: Crew Served Weapons Models 9927 and 9927A, April 1967

TM 11-5855-203-23P Technical Manual Organizational and Direct Support Maintenance Repair Parts and Special Tools Lists (Including Depot Maintenance Repair Parts and Special Tools) for Night Vision Sight, Crew Served WeaponsAN/TVS-2 (NSN 5855-00-087-3144), AN/TVS-2A (NSN 5885-00-791-3358) and AN/TVS-2B (NSN 5855-00-484-8638),  November 1977 Change 1

TB 11-5800-212-24 Procedure for Determining Serviceability of Night Vision Sight Individual Served Weapon Sight, Crew Served Weapon AN/PVS-2 and AN/PVS-2A; Night Vision Sight, Crew Served Weapons AN/TVS-2B; Night Vision SIghts, Mimiaturized AN/PVS-3 and AN/PVS-3A; and Night Vision Sight, Tripod Mounted AN/TVS-4 and AN/TVS-4A.

TC 23-13 Crew-Served Weapon, Night Vision Sight, Jan 1967

Related Equipment

See my Optics web page

Night Vision Patents

3454773 BINOCULAR NIGHT TELESCOPE WITH SINGLE IMAGE TUBE, Bulthuis et al (NV Optische), Jul 1969,
3744872 BINOCULAR WITH IMPROVED PRISM MOUNT, Akin (Bushnell), Jul 1973, - moulded plastic body
4030047 Opto-mechanical subsystem with temperature compensation through isothermal Design, F.E. Goodwin (NASA), - Beryllium
4205894 Hermetically sealed binoculars, (Bell & Howell) - single objective
4463252 Night vision goggle system, (Baird Corp), - single objective
5029963 Replacement device for a driver's viewer (ITT), - upgrades the AN/VVS-2 to a Gen III device
5084780 Telescopic sight for day/night viewing, (ITT), - single objective, single eyepiece, two internal paths
4822994 Small arms sight for use during daylight and nighttime conditions, (ITT) - removable image intensifier
Photoelectricity and Its Applications", 1949, John Wiley & Sons Chapter 18 Light Beam Signalling & Infared Detection
4629295 Night vision instrument with electronic image converter (Simrad Optronics A/S) - beam splitter
3509344 DEVICE WITH A NIGHT TELESCOPE (NV Optische) - two objectives one eyepiece
4467190 Night-vision equipment, Aug 21, 1984
4576432 Aiming or sighting apparatus with synchronously rotating thermal imager and aiming head Mar 18, 1986
4629295 Night vision instrument with electronic image converter Dec 16, 1986
4653879 Compact see-through night vision goggles Mar 31, 1987
4655562 Objective lens system, relay lens system, and eyepiece lens system for night-vision goggles Apr 7, 1987
4775217 Night vision viewing system Oct 4, 1988
4828378 Night vision viewing systems May 9, 1989
4863269 Weapon sights Sep 5, 1989
4867549 Re-imaging optical system Sep 19, 1989
5157553  Collimator for a Binocular Viewing System -
5223974 Collimator for a Binocular Viewing System -
5301060 Optical element (Minolta) - laser scanner
5347397 Diopter cell assembly for a binocular viewing system (ITT) - splitter for single objective two eyepiece systems
5444568 Consumer night vision viewing device
5455711 Magnification lens coupling device for a night vision assembly (ITT) - two adapter rings to add accy lens to NVD
5495364 Night vision binoculars (ITT) - waterproof single objective two eyepieces
5471374 Illuminator bracket for a night vision device (ITT) - breaks easily
5495364 Night vision binoculars (ITT) - waterproof single objective two eyepieces
5537261 Night vision binoculars (ITT) - commercial low cost single objective two eyepiece waterproof
5595435 Flashlight illuminator for a night vision device (ITT) -LED or Laser Diode - fits the easily broken bracket (viewer may be the 160/260?)
5737131 Night vision monocular (ITT) -
5847868 Night vision binoculars (ITT) - single objective two eyepieces low cost
6069557 Automatic long-life infrared emitter & locator system - flashing IR LED beacon (like the one that fits a 9V battery - many circuits
6219250 Night vision binoculars (ITT) - single objective two eyepieces low cost
6456497 Night vision binoculars (ITT) - single objective two eyepieces low cost
6570147 Color night vision apparatus (ITT) - RGB are split like for a TV camera, seperate Intensifiers work on the three paths where the output phosphor is the same color as the path color and then combined
H1599 Synthetic-color night vision - blends a visible color image and an IR image into a single false color image


Fort Belvoir Army Night Vision Labs - Early Attempts at Night Vision Technology - 1967 - Pulse Gated I2-TVS-2 Crew Served Weapon Night Sight
A History of the United States Army Communications-Electronics Command (CECOM)  - "Second generation night vision devices (image intensification technology) replaced the first generation "sniper scope" (near infrared technology) of World War II. The Small Starlight Scope AN/PVS-2, the Crew Served Weapons Sight AN/TVS-2, and the medium range Night Observation Device AN/TVS-4 all saw service in Vietnam. The Night Vision Laboratory, which was attached to ECOM in 1965, began their development in 1961. Production of the AN/PVS-2 began in 1964."
S.T.A.N.O. Components - Night Vision dealer

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