Retro Review: Radio Shack EC4036
Radio Shack EC4036 
Radio Shack EC4036
Company: Radio Shack
Years: most likely late 1980s to early 1990s
Type: Scientific, Programming
Number of
Steps: 40
Operating
System: AOS (postscript)
Memory
Registers: 3 (M, A, B)
Chipset: Sharp LI3301A
Sharing the Same Chipset
According to a
YouTube video from badogember
csatornája, the EC4036’s
chip set is Sharp LI3301A which is shared with many other calculators such as the
Citizen SRP145, Citizen SRP40, and Aurora TB607. This means that this calculator line up and
functions are cloned and marketed by many companies. (Link to that video: https://www.youtube.com/watch?v=iGX4Mk3gwmM
). The Logtech LC604 is also part of
this chip subset.
I am thankfully
that the EC4036 is cloned (or is a clone) because I couldn’t find a manual for
Radio Shack online (not even their website has a manual for this particular
calculator). Since the Citizen SRP145N
has the same chipset, its manual will have to do. (Link:
http://calculator.citizeneurope.com/oldmanuals
)
There is also a
discussion on the Museum of HP Calculators about the Citizen SRP145 here: http://www.hpmuseum.org/forum/archive/index.php?thread6200.html
A member of the Minimalist Club
The EC4036 has
40 programming steps. Furthermore, only
simple programming is allowed, as there are no loops, alphabetic characters, or
tests. Unfortunately, the programming is
“blind” with no way to step backwards and forwards. Programming the EC4036 will require either
trust or writing the program down first (I always do the latter).
The good news
is that you can be Statistics mode when entering programs and take advantage of
the onevariable statistics functions (mean, standard and population deviation,
sums Σx and
Σx^2).
There are two
functions dedicated to the programming mode:
HALT: Pauses
the calculator and shows the result. This is very handy. To continue execution, press [COMP].
[ x ]: I originally though that this is a integer
part function. It is not, this is the
Input function. When an [ x ] is encountered,
the calculator asks for a numeric input.
Press [COMP] to continue.
The EC4036’s
program is erased each time you start a new program, but with 40 steps, I image
that all the programs for the EC4036 will be short and will be easy to input
when required.
When
programming, program like you are actually making a calculation. This really comes into play when you want
insert a prompt step ([x]). After
pressing [x], enter a valid number to continue the calculation. Planning is definitely a key.
Keyboard
The keys are
rubbery and soft to the touch.
Thankfully, the keys are still responsive.
I wish the labeling
on some to the keys could be clearer. Here are the mapping of the most
confusing looking keys:
[A >A] (CD
CAD):
Primary
Function: Recall A. If a number is entered first, it multiplies
it by A.
Second
Function: Store the number in the
display to register A.
Primary
Function Stat Mode: Clears the last data point entered
Second Function
Stat Mode: Clears all data points
[B >B] (n Σx)
Primary
Function: Recall B. If a number is entered first, it multiplies
it by B.
Second
Function: Store the number in the
display to register B.
Primary
Function Stat Mode: Recall n (number of data points)
Second Function
Stat Mode: Recall Σx (sum of all data points)
[ MS ] (xbar Σx^2)
Primary
Function: Stores the number in register
M
Second
Function: N/A
Primary
Function Stat Mode: Recall the arithmetic mean of all data points
Second Function
Stat Mode: Recall Σx^2 (sum of all squared data points)
[ MR ] (s σ)
Primary
Function: Recalls the number in register
M
Second
Function: N/A
Primary
Function Stat Mode: Recall sample deviation (sx)
Second Function
Stat Mode: Recall population deviation (σx)
[ M+ ] (DATA)
Primary
Function: Adds the number in the display
to register M
Second
Function: N/A
Primary
Function Stat Mode: Enters the number as a data point
Second Function
Stat Mode: N/A
Your Basic Scientific Calculator
The EC4036 has
the basic scientific functions: trigonometric, logarithmic, exponential, hyperbolic,
power, factorial, and decimal/degreesminutesseconds conversion.
When the [2ndF]
and HYP is evoked, the 2F and HYP indicators take the display. For some reason I like this.
Final Verdict
A nice
collector calculator to have. I wouldn’t
pay a large amount of money for it however, I paid about $6. If you like a small programming calculator or
a challenge, this is one to consider.
Now for a few
sample programs.
EC 4036 Program: Percent Change
Input:
[COMP] new
[COMP] old [COMP]
Δ% = ( [1] – [2]
) / [2] * 100
Program:
[ x ] (enter a valid number)

[ x ] (enter a valid number)
MS
=
÷
MR
*
100
=
HALT
Example: new = 52, old = 50. Result:
Δ% = 4
EC 4036 Program: Convert
from Rectangular to Polar Coordinates
This converts
rectangular coordinates (A, B) to polar coordinates (limited).
r = √(A^2 +
B^2), θ = atan(B/A), 90° ≤ θ ≤ 90°
Program:
[ x ] (enter a valid number)
[ 2^{nd} ] [
A >A ] (store in register A)
x^2
+
[ x ] (enter a valid
number)
[ 2^{nd} ] [
B >B ] (store in register B)
x^2
=
√
HALT (display r)
1
[B >B] (recall B*1)
÷
1
[A >A] (recall
A*1)
=
tan^(1)
HALT (display θ)
Example: A = 3.5, B = 3.0.
Results: r = 4.609772229, θ = 40.60129465°,
0.708626272 radians
EC 4036: Circumference and Area of a Circle
This program
stores radius in register A and calculates the circumference and area of a circle. Here I demonstrate the multiplication feature
of [A >A].
Circumference =
2*π*r, Area = π*r^2
Input: radius [COMP] display circumference [COMP]
display area
Program:
[ x ] (enter a valid number)
[ 2^{nd} ] [
A >A ] (store in register A)
*
2
*
π
=
HALT (display circumference)
π
[A >A] (multiply π by register A)
[A >A] (multiply A*π by register A)
=
HALT (display area)
Example: r = 5.45.
Results: Circumference = 34.24335992, Area =
93.31315579
This blog is property
of Edward Shore, 2017