Month: July 2023

Welp, anoth­er cal­cu­la­tor tale of woe. This time it is a Monroe 650 cal­cu­la­tor found on eBay. The 650 is the top-end mod­el of Monroe’s 600 series cal­cu­la­tors. It is a 16 dig­it Nixie tube dis­play cal­cu­la­tor with addi­tion, sub­trac­tion, mul­ti­pli­ca­tion, divi­sion, square root func­tion, and two mem­o­ries. It oper­ates in fixed dec­i­mal or float­ing point modes, and has 5 chang­ing indi­ca­tors spaced every incre­ment of the base-10 expo­nent of three from the dec­i­mal point.
The price was right and includ­ed free shipping.

Continue read­ing “Monroe 650 Calculator repair and cleanup”