TECHNICAL DATA of the ElectroMechanical Calculator MONROE »Model1«
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Model: LA5160
Serial Number: 416982 ( green/black )
Dimensions: (ca.) Width = 11_1/2" / 29 cm
Depth = 11 " / 28 cm
Height = 6_1/2" / 17 cm
Weight: (ca.) 14 lbs / 6.5 kg
Power Supply: 110  135 V AC / DC
Mechanics: 8*10 FullKeyboard
SplitStepped Drum / Geteilte Staffelwalze
10s Carry Mechanism
Counter Stepping Mechanism + Animation
Functions: Add, Subtract, Multiply, Divide
DivisionAutomatic!
Registers: Input = 8 Decimals
Counter = 8 Decimals (NO Carry; Neg.Figures RED)
Arithmetic = 16 Decimals
Manufacturer:
MONROE Calculating Machine Co.
New York / USA
1950
H O W T O U S E the MONROE »Model1«
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BEFORE STARTING A TASK:

RELEASE the red REPEATButton (R) by pressing the red button () above.
CLEAR the KEYBOARD by pressing the lower right red Button (0).
CLEAR the COUNTER unit by turning the carriage crank clockwise.
CLEAR the ARITHMETIC unit by turning the same crank counterclockwise.
Lift and shift the CARRIAGE to the far left ( = POSITION 1).
ADDITION & SUBTRACTION:

Example: 123 + 45  6 = 162
ADD: Enter the first number (123) in the far right columns. Press the
PLUSkey (+) to transfer the number into arithmetic unit. The counting
unit displays the figure 1. Enter the second number (45). Press the PLUS
key (+) to add the number. The arithmetic unit displays the intermediate
sum (168) and the counting unit displays the figure 2.
SUBTRACT: Enter the third number (6). Press the MINUSkey (). The
arithmetic unit displays the result (162) and the counting unit is
decreased by 1.
REMARK: NEGATIVE RESULTS are displayed in the arithmetic unit
as the COMPLEMENT of the next higher 10, 100, 1000, ...
Example: 12 = 99...9988
MULTIPLICATION:

Example: 123 x 45 = 5535
Clear counter and arithmetic units. Press the right red REPEATButton (R).
Enter the multiplicand (123) in the far right columns. The multiplicator
(45) has two digits, so the arithmetic unit is moved to position 2 with a
clockwise turn of the THandle in front. Repeat pressing the PLUSkey (+),
until the first figure of the multiplicator (4) will appear in the 2nd
position of the counter unit. Move the arithmetic unit with the THandle to
position 1. Repeat pressing the PLUSkey (+), until the second figure of
the multiplicator (5) appears in the 1st position of the counter unit. The
multiplication is done: The multiplicand (123) stays in keyboard, the
multiplicator (45) is in the counter unit and the result (5535) is in the
arithmetic unit.
DIVISION:

Example: 22 : 7 = 3.1428571 Remainder 3
Division requires 3 steps:
(A) To Set the Dividend into Arithmetic Unit:

For the maximum number of decimals, pull out the arithmetic unit to the
far right position. Enter the dividend (22) in the far right columns.
Press the PLUSkey (+) to transfer into arithmetic unit.
(B) To Set the Divisor in the Keyboard:

Clear the counter unit by turning the carriage crank clockwise.
Enter the divisor (7) below the dividend (22).
Press the right red REPEATButton (R).
(C) To Divide:

Set the upper left red toggle lever to divide (:) and the machine will
calculate all decimals (and moves the carriage) automatically.
The result (3.1428571) is in the counter unit ( in RED ), and the
remainder (3) is in the arithmetic unit. The divisor (7) stays in the
input unit, therefore an additional decimal can be estimated ...
( 4, cause 4 x 7 = 28).
R E M A R K T O » M O D E L  1 « vs. » Model LA5160 «
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The LABEL on the back side is naming this calculator " NO. 1 " ...
It is the same label as the one under the OLD » MODEL1 «  MY GUESS:
Because of the commercial success of the OLD MODEL1, the MONROE Company
continued to use this "BRANDMARK" also for their newer versions ...
R E M A R K S to the missing / restored "ITEMCOUNTERCLIP":
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Because the counter has no 10scarry, there is no "buildin" counting of
the items to add. Here the "ItemCounterClip" is useful: Homemade out of
an "Aligator Clip"  When this clip is switched to the right the (1) key
is pressed, the arithmetic unit will count the items in this column(s) ...
In this case the "CLEAR KEYBOARD" Button will NOT clear this (1) key.
Have a look at the HOMEMADE POWER PLUG for 220 VAC ...
PS.: The Picture on the 100 US$ Note is Benjamin Franklin
impressum:
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© C.HAMANN http://public.BHTBerlin.de/hamann 12/15/08
