Friden EC-130 User manual

‘ 2 e
Hriden.
Z.
ee
K.
G.
Stoltenberg
bate
August
1,
1965
10
ALL
FRIDEN
OFFICES
SUBJECT COMPUTER PRINTOUT (MDD) for EC-132
HOME OFFICE CORRESPONDENCE
SAN LEANDRO, CALIFORNIA
A SUBSIDIARY OF THE SINGER COMPANY
ACTION:
REASON:
Form 70-1
File
for
future
use
when
EC-132
Calculators
become
available
in
your
area.
Servicing
of
the
EC-132
requires
the
information
in
and
included
with
this
MDD.
Re-schooling
of
personnel
is
not
contemplated
because
knowledge
of
the
EC-130
and
the
EC-132
information
furnished
herewith
should
suffice.
Included
with
the
MDD
is
a
Preliminary
Service
Manual
for the
EC-132.
The
manual
has
been
written
only
to
include
sufficient
information
for
EC-130
trained
personnel
to
adequately
service
the
EC-132.
Also
included
is
a
Logic
Block
Diagram
for
the
EC-132.
Ken Stoltenberg
Technical Publications Supervisor

Hriden, %.
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ELECTRONIC CALCULATORS
SERVICE MANUAL
riden, ye
SAN LEANDRO - CALIFORNIA
A SUBSIDIARY OF THE SINGER COMPANY

ELECTRONIC CALCULATOR 132
TEMPORARY SERVICE MANUAL
TABLE OF CONTENTS
FOREWORD
SECTION 1 - GENERAL DESCRIPTION
SIMILARITIES TO THE EC-130
DIFFERENCES FROM THE EC-130
SQUARE ROOT KEY
CLEAR DISPLAY KEY
DECIMAL POINT SWITCH
DECIMAL POINT POSITION
REGISTER 4 DATA RETENTION
ENTRY COUNTER
PILOT LIGHT
SECTION 2 - ANALYSIS OF OPERATION
SQUARE ROOT MATHEMATICS
SQUARE ROOT FLOW CHART
PHASE COUNTER
DECIMAL POINT COUNTER LOGIC
REGISTER EXPANSION
DECIMAL POSITION LOGIC
CLEAR DISPLAY LOGIC
REGISTER 4 RETENTION
ENTRY COUNTER LOGIC
PILOT LIGHT CIRCUIT
SECTION 3 - ADJUSTMENTS
NO ADJUSTMENTS FURNISHED
2-1
2-11
2-17
2-23
2-27
2-29
2-30
2-31
2-33
2-36

ELECTRONIC CALCULATOR 132
TEMPORARY SERVICE MANUAL
FOREWORD
The EC-132 is the basic EC-130 modified for Square Root
Function, Servicing the EC-132 necessitates a thorough
knowledge of the EC-130. Therefore, the EC-132 Service
Manual contains only the correlation of the EC-132 with
the EC-130 and a description and explanation of the cir-
cuits which have been added or redesigned.
Any particular area of the EC~132 which is not covered,
then, indicates that there is no change from the EC-130
and information regarding that area will be found in the
EC-130 section of the Electronic Calculators Service
Manual,

ELECTRONIC CALCULATOR 132
TEMPORARY SERVICE MANUAL
SECTION
1
GENERAL
DESCRIPTION

8-1-65 ELECTRONIC CALCULATOR 132 Section 1
TEMPORARY SERVICE MANUAL Page I
SECTION 1 - GENERAL DESCRIPTION
A. SIMILARITIES TO THE EC-130
In all but a relatively few respects the EC-132 looks exactly like the EC-130. The ex-
ternal differences are: the addition of a Square Root key to the keyboard; the change of
CLEAR ALL key to read CLEAR DISPLAY; the addition of a pilot light located in the lower
right portion of the keyboard mask; the optional addition of an Entry Counter to the right
side of the CRT mask; and a new Decimal Point Position Thumbwheel.
B, DIFFERENCES FROM THE EC-130
The internal differences of the EC-132 and the EC-130 are relatively minor with the
exception of the addition of Square Root Function Logic. All of the logic of the EC-130
has been retained intact with respect to functions other than Square Root with the ex-
ception of Clear All, which is now Clear Display and affects Registers 1 through 4
(R1-R4) only.
1. SQUARE ROOT KEY
Depressing the Square Root key on the keyboard initiates certain machine operations
that result in the square root of the number that is displayed in Rl being extracted and
displayed as an answer in the answer register (R1l).
2. CLEAR DISPLAY KEY
Depressing the CLEAR DISPLAY key on the keyboard results in the numbers in all
display registers (R1, R2, R3, R4) being discarded. This is done by inhibiting the count
in A counter (Increment A) from the delay line circuits. Since only the display registers
are affected, RS, the undisplayed storage register, is not cleared.
3. DECIMAL POINT SWITCH
In the EC-130, the Decimal Point switch was installed in the keyboard assembly. In
the EC-132, the switch has been removed from the keyboard assembly and installed under-
neath the keyboard mask in close proximity to the Decimal Point Position Thumbwheel.
Also, the switch is a completely new design that permits, with associated logic, decimal
point position in any one of the 13 display columns, or operation with no decimal point.
4. DECIMAL POINT POSITION
In the EC-130, the decimal point position was limited to one of five places. In the
EC-132, the decimal point may be positioned in any one of the display columns, or
operations performed with no decimal point. The Decimal Point Position Thumbwheel has
been slightly redesigned to locate these 14 positions (0 and 1-13) and to operate with the
new Decimal Point switch.

Section
1
ELECTRONIC
CALCULATOR
132
8-1-65
Page
2
TEMPORARY
SERVICE
MANUAL
5. REGISTER 4 (R4) DATA RETENTION
In
the
EC~130,
any
operation
involving
a
shift
down
of
data
places
R4
data
in
R3
and
places
zeroes
in
R4,
In
the
EC-132,
an
operation
involving
shift
down
retains
R4
data
in
R4
and
repeats
R4
data
in
R3.
In
effect,
then,
R4
becomes
another
storage
register
for
the
retention
of
data.
However,
in
any
operation
involving
shift
up
R4
data
is
discarded,
as
is
the
case
in
the
EC-130.
6. ENTRY COUNTER
The
Entry
Counter
(optional)
in
the
EC-132
permits
a
total
to
be
kept
of
the
number
of
entries
of
a
group
of
entries
as
they
are
placed
in
the
machine.
The
Entry
Counter
is
a
four-digit
counter
that
is
installed
on
the
right-hand
side
of
the
CRT
display.
A
RESET
button
is
included
to
permit
reset
of
the
counter
to
zero
before
the
initiation
of
a
new
group
of
numbers.
7. PILOT LIGHT
In
the
EC-130
and
EC-132,
dividing
by
zero
keeps
the
machine
in
an
operational
loop
that
keeps
the
Display
blanked.
In
this
condition
there
is
no
Display
indication
that
the
machine
is
on.
If
the
machine
should
be
covered
while
On,
heat
build-up
could
cause
damage
to
semi-conductors
and
to
other
components.
In
the
EC-132,
a
Pilot
Light
is
in-
stalled
at
the
lower,
right-hand
corner
of
the
keyboard
mask
that
indicates
an
On
condition
when
power
is
applied
to
the
machine.

ELECTRONIC CALCULATOR 132
TEMPORARY SERVICE MANUAL
SECTION 2 ANALYSIS of OPERATION

8-1-65 ELECTRONIC CALCULATOR 132 Section 2
TEMPORARY SERVICE MANUAL Page l
SECTION 2 - ANALYSIS OF OPERATION
A. SQUARE ROOT MATHEMATICS
The EC-130 uses a modified 'Sum of the Odd Integers'' method of extracting a square
root, The method usually taught in school is not easily adapted to digital techniques, thus
another system must be used. The sum of the odd integers is but one of many ways of
arriving at a square root.
Odd integers are the whole numbers 1, 3, 5, 7, 9, 11, etc. If such a succession of odd
integers, (odd-order arithmetic progression), are added, each summation will result ina
perfect square. A perfect square is a number whose square root is a whole number. The
following table illustrates this.
1) 1402121
2) 14354 =2?
$y 1a 3-63 9 2 3
4) Lie Se 5 eS 16 Sa?
5) 143454749525 =5°
By adding the next higher odd order integer to each preceding summation, all existing
perfect squares are produced, and none is omitted. Note that the NUMBER of odd order
integers in each summation IS the square root of the sum. In example 5, there are 5 parts
to
the
summation,
and
5
is
the
square
root
of
25.
This
holds
true
for
any
combination
of
successive odd integers.
As another example:
l+34+4 5+ 749411 + 13 =49
1; 2; 3; 4; 5; 6; 7;
2
Therefore, \/ 49 =7
By reversing this procedure, the square root can be extracted. In this case, we
SUBTRACT successive odd integers to arrive at the root, starting at l.
For example:
16 15 12 7
- 1 - 3 - 5 at
15 12 7 0
(1) (2) (3) (4)
Therefore, MG ae

Section 2 ELECTRONIC CALCULATOR 132 8-1-65
Page 2 TEMPORARY SERVICE MANUAL
The
number
of
successful
subtractions
is
the
square
root.
If
a
larger
number
is
used,
more
subtractions
are
necessary.
64 63 60 55 48 39 28 15
oe ee ee es
63 60 55 48 39 28 15 0
(1) (2) (3) (4) (5) (6) (7) (8)
The square root of 64, then, is 8.
This
is
a
satisfactory
method
for
use
with
perfect
squares.
A
slight
change
is
necessary,
however,
to
alter
the
method
for
numbers
that
do
not
have
an
integral
square
root.
Rather
than
count
the
subtractions
to
arrive
at
the
root,
we
can
apply
a
simple
formula.
2
.
In the last example, (,/ 64), note that the last number successfully subtracted is 15.
Adding
1
to
this,
(15
4
1
=
16),
then
dividing
by
2,
(16/2
=8),
gives
the
square
root
in
another way. Expressed as a formula:
=(n+
1)/2,
when(R
}s
the
last
integer
to
be
successfully
subtracted,
(no
over-
draft),
and
is sometimes
called
the
"partial
root!'.
An example will show the complete method developed so far.
100
99
96
91
84
45
64
51
36
19
a
A
A
OR
99 96 91 84 75 64 51 36 19 0
he ee a ea =10
Thus, the square root of 100 is 10.
The method developed to this point is perfectly valid for small numbers, but it is
cumbersome
for
large
numbers.
Since
the
number
of
subtract
cycles
is
equal
to
the
square
root
of
the
number,
an
excessive
length
of
time
is
necessary
to
complete
a
problem
using
large
numbers.
To
avoid
this,
another
change
must
be
made.
Starting at the decimal point, the number is divided into pairs of digits, called couplets.
Beginning
at
the
most
significant
couplet,
the
answer
can
be
derived,
one
digit
being
pro-
duced
for
each
couplet.
However,
the
couplets
must
be
operated
upon
in
a
way
that
is
somewhat different than was done in the previous examples.
If
the
number
that
is
to
have
its
square
root
extracted
is
441,
it
appears
as
04
41
when
divided
into
couplets.
The
root
of
each
couplet
will
become
one
digit
of
the
final
square
root,
which
will
have
2
digits
to
the
left
of
the
decimal
point.
However,
the
root
of
04,
and
the
root
of
41
cannot
be
combined
in
any
way
to
produce
the
root
of
the
original
number.
The
following
example
will
serve
to
illustrate
the
method
used
with
the
couplets.