The keyboard has a matrix with rows and columns. So it is possible to test the incoming signals to the outputs where places for diodes have been left open. Maybe the square root is hidden there. I once succeeded in finding the whole set of trigonometric functions which were provided in the chip but not wired to the keyboard. It was a much later version of a calculator (in 1981) with models of different complexity.
I have a Monroe 650 and it does have the square root key. It is between the division and subtraction keys. Other than the missing key they are the same internally. Almost identical to a Canon Canola L163 except the L163 and a % key while the 650 has better memory function. They use the exact same circuit board and to change it from a 650 to a L163 you just move a jumper that is marked L163 650.
I noticed that lap counter thing straight away, that would be really useful for double checking I'd added up a column properly. And that RV button, the number of times I get values switched when trying to calculate £/g
Similar in many ways to my old Canon "Canola" 161S. Same kinds of reed switches, lots of Nixies, but it is older than this one in the video....it has no LSI chips, instead it has a card rack with several large boards plugged in, all using LOTs of pre-TTL simple logic gate ICs to do everything. Because it has no solid state memory, it has an acoustic delay line (externally it looks like an old early 1980s vintage HDD) where a cycling series of 1s and 0s exist as pings or no pings on a long wire that is coiled up inside, plucked electromagnetically, and read back the same way, and strings of several numbers are constantly held in this, going around and around, modified on the fly as needed by whatever function is being done by the logic. It is kinds hard to believe that such a sophisticated calculation of large numbers, plus all the oddball extra functions and variable number of digits and such can be accomplished by just a few cards worth of discrete logic. Mine worked when I bought in on eBay, except one of the keys had a dead reed switch. I was not able to find a suitable replacement, so I just relocated it to one of the rarely used switch positions, swapping reed switches to get the more important key working again.
It is a beauty :-) My 'old' Casio college fx-100 has a RV function. It is marked X Y with a double pointed arrow in the middle. I loved this function at school.
So I thought Id mention this channel "Dalibor Farný" A small company that is bringing back, and also learning to manufacture really huge Nixie Tubes from scratch.
Impressive, but the HP calculators of the day utilized RPN and featured a 7 segment LED readout. I remember being totally flabbergasted by the HP-45, circa 1973.
@@gyrgrls Well you could, however, if your memory is bad then it is easier to do better than the 22/7 I was taught in school decades ago without much effort in memorising. After all, splitting 113355 into two three digit numbers and making the bigger one the numerator isn't a stretch, though I personally just hit the π key when it is available.
Your HP calculator will show 31 or 32 digits by hitting shift > show (not shitshow). My HP42S does. The power connector looks like an XLR? Imagine the damage you could do by plugging that cord into a mixing console.
13:25 Contrary to popular belief these old reed switches can oxidize on the inside or stop working for other reasons. I have had to replace some on vintage calculators. I have also had to replace faulty keyboard diodes on a Canon calculator, so you might want to check the diodes as well.
3:16 The constant button usually works a bit different on vintage calculators. For example you can do 3 * 2 = 6, then press 4 = and it will do 4 * 2 and display 8, etc. Maybe you can check if the Monroe also does that in addition to just pressing = to display the last answer * 2. It should also work for division.
Maybe accumulating both nominators and denominators has something to do with fractions. For example if you calculated 1÷2 then 2÷3 then 3÷4 you'd end up with 1+2+3 (6) & 2+3+4 (9) in the accumulators. Don't know if that's useful for anything,
