In the late 1960s and early 1970s, before the invention of LED and LCD displays, so-called Nixie tubes were one of only a few technologies cheap and compact enough to be used in electronic calculators. They were fairly power-hungry, so their use was mainly confined to mains-powered desk machines. A Nixie tube contains a stack of cathodes in the shape of the numerals from 0 to 9, and a wire mesh anode through which the cathodes can be seen. A distinctive and consequent feature of the design is that the illuminated numerals vary in depth, with the furthest ones substantially obscured by those in front. In the case of the Remington immediately below, the 2, 6, 7 and 8 are noticeably brighter.
Sperry Rand Remington 1211
Serial No. 806801
Capacity: 12 digits
Price paid (including postage): £31
This is a Sperry Rand Remington calculator, which is actually a re-badged Casio machine.
Canon Canola L163
Serial No. 301535
Capacity: 16 digits
Price paid (including postage): £29.49
This machine is more capable than the Remington, featuring as it does a square root function and two memories (and 16 digits!). The only fault with the machine is cosmetic – the +/= key is misaligned, but works fine. It’s probably an easy fix, but I really don’t want to take the cover off a machine that is otherwise perfect.
The machine went fairly cheaply on eBay – the description missed out the very important words “Nixie” and “Calculator” (it was described as an “adding machine”)
Monroe Model 620
Date: ca. 1971
Price paid: £3.20
This machine bears more than a passing resemblance to the Canon, and for a very good reason – it’s essentially a Canon machine with a Monroe badge. The nearest match in the Canon range is the Canon Canola L121, which is very similar but for the styling of the case and the Monroe having one more digit in the display.
This was a very cheap eBay purchase, which probably slipped through the net because the magic “Nixie” word was missing from the description.
Date: ca. 1973
Price paid: £5
Another cheap eBay purchase. This machine doesn’t have Nixie tubes, but the Panaplex display is closely related. It has a set of adding machine keys in addition to the calculator keys one would normally expect to see.