Melcor 888 - Francis WEB

MELCOR is a company that was popular in the 70's, making LED calculators. Here is an ad from Popular Science (October 1975) showing the price of these machines, delivered as a kit:


Apart from the classic calculators, MELCOR tried to manufacture one with its own version of RPN (Reverse Polish Notation). If you are familiar with this entry mode, you know that you have to enter the first number, then the second number, and finally type the operation ( + - / X ). There is no "=" sign on an RPN calculator.
The MELCOR 888 has no "=" sign, but it has no "ENTER" sign either.  So how do you work it?
look at the video below. The idea is to use the "+" sign as the enter. Let's say you want to add 8 and 6, you will have to type
8 + 6 +
If you want to multiply 35 by 23 you will type
35 + 23 X

I know, confusing...
So anyway, they tried to do that in the Model 888 shown below


Here is a short video demonstrating how to use this device