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Part II: Production
(continued)
Power
Power for the Snooperscope and Sniperscope was provided by a power supply, power cable, and 6 volt battery.
Those used with the Snooperscope were no different than those used with the Sniperscope. Except for the wording on the label of
their power supply. Three batteries were supplied with each set.
The power supply and battery were two separate self-contained units. The two units were secured to one another using
small trunk type hasps and carried within a knapsack on the operator's back.
One end of the power cable was connected to terminals within the power supply and hermetically sealed where it entered
the power supply body to prevent moisture from entering the power supply. The other end of the cable was connected to terminals
inside the scope and hermetically sealed to the scope where it entered the scope body. This arrangement made the scope, power cable,
and power supply inseparable during field use. Repairs or maintenance that required breaking the seals necessitated the work be done
by a rear echelon maintenance unit capable of resealing the cable connections. A leakage path caused by the amount of moisture present
in a fingerprint was often enough to cause failure of the equipment.
The majority of both housings (if not all) were originally
painted light gray. Some were later repainted black.
Power from the battery was supplied to the power supply via two banana type plugs.
Power to the scope was provided via the cable.
(All Hands Magazine, June 1946)
Movement of the knapsack on the operator's back was minimized using M1936 Regulation
Government Issue suspenders attached to a M1936 pistol belt.
| Power Supply (Model 1450) |
Manufactured by Electronic Laboratories in Indianapolis, the power supply converted 6-volts D.C. supplied by the battery to the 4,250 volts D.C.
needed to operate the scope. Its case was made of steel.
| Power Supply Specifications |
| Height: | 5 3/4" |
| Width: | 8 1/2" |
| Depth: | 2 7/8" |
| Weight: | 4 lb. 1 oz. |
(Power Supply height and width are reversed in Ordnance manuals - above has been corrected)
The Power Supplies had serial numbers stamped in the metal below the right half of the label.
They are sometimes hard to see absent cross lighting and/or close examination. Those for the
Snooperscopes were a different sequence than those for the Sniperscopes.
Serial Numbers with Labels
(observed to date) |
| Snooperscope Power Supplies: | 1701 - 3295 |
| Sniperscope Power Supplies: | 5153 - 5967 |
M-1 power supplies could be (and were) used with M-2 Sniperscopes (early and late). Those
later repainted often have the label removed with the serial number still present. The only external differences that
may identify the power supply as having been made for one of the M-1 scopes is the presence of a serial number and/or
the power cable connector cap (refer cable section below) if the power cable wasn't replaced. M-2 power supplies
had no serial numbers and an octagon shaped connector cap allowing the cap to be adjustable with a wrench.
The area under the terminal connector board contained the transformer, condensers, resistors, terminal
boards, and other sensitive high voltage components that were potted in wax for protection from moisture
and are not serviceable. Any attempt to open it will very likely destroy its contents.
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 |
Click on the image to open an enlarged version in a new tab.
Right click and select "Open Link in New Window" for a side to side comparison with the chart and narrative that follows.
| ! WARNING !
This chart and the narrative that follows are intended for use with the schematic diagram above
to help communicate the basic concept of how this works.
This is NOT to be used as instructions for how to make it work.
Do NOT open the power supply unless you are a qualified electrician. The high voltage within is dangerous.
|
| Post | Color | | Connection |
| A+ | | Battery +6 VDC to S1 (switch) and ... | Red wire via power cable to Lamp +6 VDC
|
| A- | | Battery -6 VDC to chassis ground and ... | Yellow wire via power cable to Lamp -6 VDC
Green Wire via power cable to Image Tube* |
| Power to Image Tube |
| B +1 | - | High Voltage from Rectifier | Thick Black wire via power cable to Tube Socket pin 1
Powers Tube Grid 4 |
| B +2 | | 185-835 VDC from P2 (potentiometer) for image focus | Small Black wire via power cable to Tube socket pin 7
Powers Tube Grid 3 |
| B +3 | | 100 VDC from resistor connected to P3 (potentiometer) | White wire via power cable to Tube Socket pin 6.
Powers Tube Grid 2 |
| Potentiometer |
| P1 | - | 835 VDC to Potentiometer | potentiometer (left) |
| P2 | - | 185-835 VDC to B +2 | potentiometer (center) |
| P3 | - | 185 VDC to resistor, 100 VDC to B +3 | potentiometer (right) |
| Switch |
| S1 | - | +6 VDC from A+ to Switch | Switch input |
| S2 | - | +6 VDC from Switch to Vibrator (VR) | Switch output |
| Vibrator |
| VR | | +6 VDC from S2 (switch) | Vibrator (VR) |
| VS | | Rapid intermittent 6 V output to Transformer | Vibrator (VS) |
| VC | | Vibrator ground | Vibrator (VC) |
+6 VDC from the battery flows to A+ (Red) power cable to the infrared light source as well as to the power supply on/off switch.
The infrared light source is operated by a separate on/off switch in the mount it is attached to.
-6 VDC from the battery connects to A- (Yellow) with -6 VDC routed to chassis ground connection on the power switch. The chassis ground carries -6 VDC via
the cable's inner and outer shield to the light source along with the scope ground at tube socket pin 4. * The manual indicates the cable to
pin 4 is green but may be bare wire.
When the power supply switch is turned on 6 VDC flows to the vibrator (VR Brown). The vibrator creates a rapid intermittent current to the transformer (VS Blue).
Transformers require an alternating current to function. The rapid intermittent voltage generated by the vibrator creates a rise and fall of voltage that emulates an
alternating current.
The transformer steps up the voltage to a potential 4,250 VAC. This then flows into the rectifier tube which converts the alternating current to direct current (AC to DC).
The high VDC flows to B +1 (large black) then on thru the power cable to the tube socket and into the image tube socket pin 1 to power Grid 4.
The high voltage DC also flows to a voltage divider circuit composed of a series of different resistors where different voltages can be tapped.
At P1 the voltage is dropped to a potential of 835 VDC and goes into the potentiometer.
The potentiometer allows the voltage to be varied for the purpose of focusing the electronic image. The variable voltage flows to
B +2 (small black) then on thru
the power cable to the tube socket pin 7, where it enters the image tube and powers Grid 3.
185 VDC from the potentiometer goes to P3. From there a resistor drops the voltage to about 100 VDC at the B +3 connection (White). The white wire connected to B +3 goes
to the power cable and to tube socket pin 6, where it enters the image tube and powers Grid 2.
On the tube socket, there are resistors between pins 6 & 5 as well as pins 5 & 4 (ground) which completes the voltage divider circuit. This provides 20 VDC at pin 5 for grid 1.
The power pack on/off switch is the on/off switch for the telescope. The power pack potentiometer knob is the electrostatic focus of the image tube.
|
 |
Vibrator, Type R-170, manufactured by Electronic Laboratories.
|
Rectifier Tube, RCA Type 1654
 |
 |
Case Cover, part #M1746
 |
Case Cover Gasket, part # N-622-B
The power cable contained 5 wires wrapped by a shield. The shield provided to reduce electrical noise and
was connected to the ground wire. The remaining 4 wires carried the various voltages needed for the image tube
and light source. The cable was hermetically sealed where it entered the scope body and power supply.
The cables were manufactured by Simplex Wire & Cable Co. of Cambridge, MA.
Wire A+ supplied the 6 volts for powering the light source.
Wire A- supplied the negative and was also connected to the shield cable.
Wires designated "B" were related to the high voltage required by the image tube.
The power cable connector cap for the M1 power supplies was an electrical conduit cap
manufactured by Ralco Mfg. of Chicago, IL. This cap was specific to the M1 power supplies
and readily identified by its raised vertical lines. The manufacturer name and part number
were also present but sometimes wore down with use over time.
The 6 volt line connected to the cable at the rear of the grip switch. Wires related to operating the image tube
entered the telescope and connected to the Socket Assembly. The Socket Assembly inner connectors slipped over the
connectors on the image tube.
The power cable support
| Battery Assembly (Model 1451) |
The Battery Assembly consisted of a metal case with the 6 volt battery and a cover assembly
with fuses, charging receptacle, and the two banana plug receptacles for routing the power
to the power supply.
Battery Assembly Specifications
|
| Height: | 7 5/8" |
| Width: | 8 5/8" |
| Depth: | 2 3/4" |
| Weight: | 11 lb. 8 oz. |
(Battery height and width are reversed in Ordnance manuals - above has been corrected)
The width and depth of the battery were less than that of the metal case, Wood panels were used to fill the space
around the battery and secure it within the case. A wood slat in the top of the case held the battery away from the metal.
The battery sat on another wood slat attached to the inside of the cover assembly.
|
|
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Front View
(as new)
Rear View
(as new)
The batteries were a 6 volt, 3-cell non-spillable sulfuric-acid storage battery manufactured
by Willard Storage Battery Co. of Cleveland, OH.
| Discharge Rate: | 25 amp hours at 5 amp |
| Operating Time: | approx. 4 hours (2 hours actual running time) |
| Recharge Time: | approx. 8-10 hours |
| Recharge Lifespan: | approx. 50 cycles (recharges) |
| Operating Temperature: | 40-130 degrees F |
The operational life of new batteries was shorter than the rated capacity.
The battery would reach its rated capacity of 25 ampere-hours after 6 or 8 cycles.
Each cell was filled equally with sulfuric acid (red cap) using a 1" laboratory
funnel manufactured by Bryant Electric Co. of Bridgeport, CT.
Each of the three cells had a set of 3 balls. Tilting the battery forward 45 degrees all
three balls would float vertically when the battery was fully charged. The green ball hit
bottom when the charge was at 75%, white at 50%, red at 25% of full charge.
ER-25-6 was Willard's part number for the set of three.
The date of manufacture was 6-44.
A Littelfuse 3AG 15 amp fuse protected the battery. A second was attached as a spare.
Banana plugs on the bottom of the power supply inserted into receptacles opposite the two hex nuts on the left.
Charging Cable Assembly
For "emergency charging" in forward areas each Snooperscope and Sniperscope were provided with a
4-foot rubber-coated recharging cable manufactured by Consolidated Wire Corp. in Chicago, IL.
A plug on one end connected to the recharging receptacle on the front of the battery. Two battery
clips were attached to the other end.
The recharging cable was carried in the top of the knapsack on the side away from the operator's back.
| Recharging Rack & Generator |
The primary method intended for recharging batteries was a recharging rack powered by a Model 3DP6-6 gasoline motor/generator.
Procurements for the Snooperscopes and Sniperscopes included 215 recharging racks and battery-charging generators with one
per each set of 10 Sniperscopes or Snooperscopes.
Recharging batteries usually required the batteries to be transported to a rear area after daybreak and returned to the front before nightfall.
Active combat and/or severe weather could prevent these logistics.
| Charging Rack Specifications |
| Height: | 7" |
| Width: | 8 3/4" |
| Length: | 37" |
| Weight: | approx. 25 lbs. |
| Capacity: | 4-12 batteries |
| Manufacturer: | Electronic Laboratories
Indianapolis, IN |
Model 3DP6-6
Generator Specifications |
| Height: | 17" |
| Width: | 12 1/2" |
| Length: | 17 7/8" |
| Weight: | approx. 85 lbs. |
| Watts: | 350 |
| Volts: | 6-8 |
| Manufacturer: | Atlas Aircraft Products
New York, N.Y. |
Batteries were mounted to banana plugs on the top of the Recharging Rack. A safety pressure
switch activated the current when the battery was fully seated. Batteries were secured to
the rack using their luggage hasps for attaching them to the power supply.
Carry bags
The Snooperscope Carry Bag was designed to carry and protect the fully assembled Snooperscope.
The bag was constructed of canvas with heavy leather to support and protect the scope and light assembly.
TM 5-9340 image of pre-production Snooperscope Bag and pre-production Knapsack absent leather.
The fully assembled Snooperscope was placed in the bag upside down
with the scope at the bottom and hand grip pointing up.
N-716 was the part number
As with the Snooperscope, the Sniperscope Carry Bag was designed to carry and protect the fully assembled Sniperscope with carbine.
The bag was constructed of canvas with heavy leather to support and protect the scope and light assembly. The carbine and scope
sat upright within the bag.
| Sniperscope Carry Bag Specifications |
| Height: | 15" |
| Width: | 8 3/4" |
| Length: | 37" |
| Weight: | 1.9 lbs. |
The protruding "nose" at left held the carbine barrel. The leather on the forward bottom protected the
light assembly. The leather on top of the bag was inside the zipper and protected top of the scope.
N-717 was the part number
Power Supply & Battery
Knapsack/Backpack |
The knapsack/backpack holding the power supply and battery was used with both the Snooperscope and Sniperscope.
The bag was constructed of canvas with a leather bottom. The battery sat upright. The power supply was inverted.
A hole in the leather on the bottom of the knapsack allowed the power cable to pass and gave access to the power supply
controls.
| Knapsack Specifications |
| Height: | 12" |
| Width: | 3 3/4" |
| Length: | 9" |
| Weight: | 1 lbs. |
| Loaded: | 13 lbs. 10 oz. |
The scope with it's attached cable was passed through the top of the knapsack and out through the
bottom zippered portion that was then zipped closed leaving the cable within in the hole. The
powerpack with battery followed through the top of the knapsack oriented so the powerpack
controls and cable would rest within the hole for access to the controls. The flap on top
of the knapsack was then secured.
The bottom strap connected to the rear of the pistol belt.
Suspenders & Belt
Government issue M1936 Suspenders and M1936 Pistol belt were used as load bearing equipment with various
different uses separately or together. To include securing the Snooperscope and Sniperscope backpack.
Maintenance & Repair
Four kits were assembled by Electronic Laboratories based on anticipated needs.
Spare Parts
Kits |
| Electronic Labs Kit | Maintenance Type |
| Model 1557 | Mobile Maintenance, 1st echelon |
| Model 1558 | Snooperscope, Maintenance, 4th echelon |
| Model 1559 | Sniperscope, Maintenance, 4th echelon |
| Model 1560 | Battery Spares |
First echelon maintenance was performed by the operator/user and limited to minor repairs such as replacing rubber eyeshields, filters, lamp bulbs, and replacing or
recharging batteries.
Due to the high operating voltages and the need for waterproof seals on the power supply and telescope, anything further was the responsibility of
personnel specially trained in optical and electrical maintenance (fourth echelon) assigned to various companies within each Division.
Disassembly and servicing of the telescope, power supply, light grip switches, and mounts were accomplished using standard screwdrivers, pliers,
soldering iron, and ohmmeters. Kits for fourth echelon maintenance and repairs were issued on the basis of one per 10 Snooperscopes and/or Sniperscopes.
| Supplies |
| Item | Quantity | Source | Used For |
| Clear Glyptal 1202F | | GE Supply Co.
Indianapolis, IN | sealing varnish on the threads of the lens assemblies to the telescope housing |
| White Shellac | 2 oz. |
| thread locker for the lens retaining rings and set screws |
| Sealing Compound | 1 lb. | Stevenson Bros.
Philadelphia, PA | making waterproof seals for the telescope |
| Cordo No. 70 Cement | 2 oz. | Cordo Chemical Co.
Norwalk, CT | |
| Lens cleaning fluid, P-70 | 8 oz. | Commercial Solvents
Terre Haute, IN | cleaning lenses and as a solvent to soften the white shellac and glyptal |
| Lens tissue | 2 pkg. | Denver Fire Clay
Denver, CO | cleaning lenses |
| Lens cleaning cloth | 1 pkg. | Kleeno Mfg. Co.
St. Louis, MO | cleaning lenses |
| Item | Description |
Flat blade screwdriver,
9/32" (1)
(approx. 6.5" long) |  |
Flat blade screwdriver,
3/16" (1)
(approx. 6" long) |
Jewelers screwdriver,
.10" blade (1) |
Jeweler's screwdriver,
.040" blade (1) |
The Jeweler's screwdriver with .040" blade was used for removing
sealing compound when disassembling lens assemblies.
| Item | Description |
Open-end wrench,
1/2" (1) |  |
| Used For: | removing and installing the power switch and the focus rheostat on the power supply | Source: | Indestro Manufacturing, Chicago, IL |
Sealing
compound tool
(1) |  |
| Used For: | making waterproof seals for the telescope | Source: | Stewart Warner Corp.
Chicago, IL |
| Nozzle, custom (1) | Source: | American Screw Products
Indianapolis, IN |
Wrench,
adjustable
(1) |  |
| Used For: | loosening/tightening the nuts that retain the power cable to the power supply and telescope | Source: | Boos Tool Corp.
Indianapolis, IN |
Strap
wrenches
(2) |  |
| Used For: | removal and replacement of the lens assemblies | Source: | J.C. Joyce Associates
Los Angeles, CA |
 |
| Item | Source | Used For |
| A | Wrench handle
w/ set screw (1) | Metal Industries Inc.
Indianapolis, IN | wrench heads |
| B | Wrench head,
1 7/8" (1) | removal and replacement of the
objective lens front retaining ring |
| C | Wrench head,
1 3/8" (1) | removal and replacement of the
objective lens rear retaining ring |
| D | Wrench head,
1 3/4" (1) | removal and replacement of the
reticle retainer ring |
| E | Wrench head,
15/16" (1) | removal and replacement of the
retaining ring on the eyepiece assembly |
| F | Pin Wrench,
1 1/4" (1) | removing the stop ring on the
eyepiece assembly |
Post WWII
The outbreak of war in Korea in 1950 prompted a second production run of 1700 M2 Sniperscopes that brought with them
TM 5-9341 Operation and Maintenance Instructions for Sniperscopes Model M1 and M2 (Aug 1951) and
TM 5-9341A Repair Instructions for Sniperscopes Models M1 and M2 (Aug 1951). These manuals indicate, apart from the
lens tissue, lens cloth, and lens cleaning fluid the supplies and tools above were classified as obsolete.
The lens assemblies were no longer considered field serviceable. They would be swapped out and sent for repair at a more
environmentally controlled facility.
The 2 strap wrenches specific to the T120/M1 scopes were replaced by a
chain wrench used with a specially designed Telescope Clamping Vice
designed to hold either the M1 or M2.
The width of the head of the chain wrench was ground down to fit the space between the objective lens and front scope ring.
Manufactured by the Owatonna Tool Company of Owatonna, MN
The handle and wrench (Wrench Head, 1 3/4", shown above as D) used for
removal and replacement of the reticle retainer ring were replaced by a
Guided Spanner Wrench. Shown above with an M2 Sniperscope.
A 2nd echelon (Organizational Mechanics Maintenance) was added for scope adjustments, replacing image tubes, changing rectifier tubes,
charging the battery, and charging rack repairs. They were equipped with a complete set of mechanics' general-purpose tools and
supplies.
Additional changes that applied to both scope models are covered in the history of the M2 Sniperscopes.
The story continues with...
Sniperscope & Snooperscope
Model M1 |
Part III: Deployment
|
| Click Here | |
References
[1] "Report 908, Snooperscope and Sniperscope, Project XR 441", 30 Jan 1945, Capt. Edmund R. Ricker, Corps of Engineers,
Fort Belvoir, Virginia
[2] Army Ordnance Telescopes Report, Fire Control Sub-Office, Frankford Arsenal, Philadelphia, PA, 5 Sept 1944
[3] The Ordnance Department: Procurement and Supply, by Thomson & Mayo, Center of Military History Washington D.C., 1960
[4] Indianapolis Industries, The Indianapolis News, 21 Mar 1946
[5] Alphabetic Listing of Major War Supply Contracts, Cumulative, June 1940 through September 1945, Civilian Production
Administration, Industrial Statistics Division, 1946
[6] E-L Breaks Story of SS Equipment The Electronic Beacon, Electronic Laboratories employee newsletter, April 1946
[7] Infantry Board Report #1595, Fort Benning, GA, 20 Apr 1944
[8] TM 5-9340 Snooperscope and Sniperscope, 1 Sep 1944
[9] Sperry Gyroscope Company Division records, Hagley Museum and Library, Wilmington, DE 19807
[10] TM 5-9341 Operation & Maintenance Instructions for Sniperscopes, Models M1 & M2, Aug 1951
Credits
Many different people have contributed to make these web pages on the Model M1 Snooperscope & Sniperscope possible. Thank you, everyone.
We'd like to especially acknowledge the following individuals whose contributions have been significant. In alphabetical order:
|
Marc Beaudry,
Rick Larson,
William Morris,
Jason Patrick (Historian's Office, U.S. Army Engineer School),
Marcus Rust,
John Spangler,
Andrew Stolinski (Archival Research Group),
Eric Nicolaus (Nicolaus Associates)
|
Online Resources
Articles | | Infrared Forum |
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The Newsworthy section of our forum has a number of different articles that include various articles on the infrared scopes and equipment used with the .30 cal. Carbines.
Go to the Articles
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In addition to providing a means to communicate with other owners and those of us doing the research, there are short articles on the various aspects of
the infrared equipment. Also, several posts on the ongoing research showing contract numbers, dates, quantities, serial number blocks, and more are
updated as additional information becomes known.
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© Copyright 2012-
The Carbine Collectors Club. All Rights Reserved.
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