Collection Item

Home | Contact

Monroe 326 Scientist

Brand: Computer Design Corporation (Compucorp) OEM for Monroe.
Model: 326 Scientist.
Origin: Los √Āngeles, California, USA.
Introduction: 1974.
Type: Portable advanced scientific and programmable calculator, works with 4 D rechargeable batteries or with AC power.
Functions: Scientific calculator with advanced programming capability. No permanent memory. Only display, no printer. External magnetic tape unit for storage.
Display: Panaflex II display with 16 digit. Each digit contains 7 standard segments for numerals plus 2 indicators for decimal point and thousands separator. Negative numbers are displayed with "-" at the left of the first digit. Overflow error is displayed as "E---".
Keyboard: 43 big keys plus 3 sliding switches for angle selection (gradients or degrees), Operation mode (Normal/Run, Step run or Load Program), Data to read or write (Program or Registers).
Main chips: Texas Instruments.
Logic comments: This is the most advanced model of the Compucorp 300-Series of specialized portable calculators. You can perform the following types of functions:

- Basic arithmetic operations with 4-level parenthesis.

- Additional arithmetic functions like Square root, Reciprocal, Raise to a power, Factorial, etc.

- Logarithmic and trigonometric functions and their inverses.

- Statistical functions.

- Rectangular and Polar coordinates conversion.

- Metric and English unit conversions.

- Also have an auto-diagnostic function to test the calculator itself.

This calculator have 12 working registers (instead of 10 of the previous models) to store intermediate results.

This calculator have a true programming capability with branch and conditional instructions, labels, subroutine processing and program editing. You can review and debug a stored program, you can add, change and delete instructions, also you can run a program step by step for debug purposes. This capabilities are not seen on previous models like the Compucorp 324G.

It can be connected to a external magnetic tape unit (Compucorp/Monroe 392) to store programs and memory contents. Unlike the previous models, the 326 have only one program area (The 324G have 2 program areas!), but by program control you can "swap" program segments between tape and memory to make huge programs up to 10.000 steps in only one tape cassette! Only one program can be loaded in memory at a time, but the whole library resides on tape. Also you can write the contents of the 12 working registers for a later recall.

Also there is a Teleprinter interface unit (Compucorp/Monroe 395), but I have no information about it.
Size: Calculator: 8.86 x 5.43 x 2.76 in, 225 x 138 x 70 mm.
Tape unit Monroe 392: 8.07 x 5.04 x 2.83 in, 205 x 128 x 73 mm..
Accesories: Original wood-made hard suitcase (must be restored!), external magnetic tape unit Monroe 392, external multi-voltage power adapter. Also I have 2 endless tape cassettes with the plastic box and 1 standard tape cassette, this time without box, all with the brand Compucorp. This cassettes have hand-written descriptions of the programs and data stored from the original or previous owner.
Condition: Monroe 326: (8/10) Very good, no marks on casing, only minimum marks on handle, working.
Tape unit Monroe 392: (10/10) Pristine, like new, probably unused, working.
Download: Monroe Beta 326 Scientist (Compucorp 326) Calculator user manual, click here.
The 300 Series Beta Computers - Field Service Manual,, click here.
Source of both manuals:
Brief operating instructions printed at the back of the machine, click here.
Instruction codes printed on the sliding label, click here.
Also I have the cover of a Compucorp endless tape cassette for use with the unit Model 392,
click here: Page 1, Page 2.
Additional readings: You can read a complete article the 300 Series, including the 326, clicking here, from
Also you can read an excellent article about the history of Compucorp here, from
Please see my Compucorp 324G.


Home | Contact