Victor 1900 [unknown membrane?]

User avatar
zrrion

11 Apr 2021, 23:12

Image
Looking at it it seems at least outwardly similar to other victor calculators that I have seen. I have a different model from '79 in very bad condition that uses SKCC cream so I was thinking this was possibly some early alps switch.

Weird oddity, this calculator is also a 1900: http://www.vintage-calculators.nl/page50.html but is clearly not the same adding machine. 1900 appears to be the product line, not a specific model number. From the description:
The keyboard uses conductive rubber sheets on a PCB. The keys press the rubber sheets against the PCB’s circuits. Although it’s probably not as sustainable as reed relays which were often used those days, it still feels like a high quality construction and works flawlessly after so many years.
it would seem that the calculators use the same switches. It is actually pretty rare that a vintage calculator website would document the switches at all so that is fortunate that in this case it is confirmed. If anyone wants to get ahold of these switches with a proper display instead of a printer then the calculator described on that page is a good lead.

Image
The listing included a power cable but they left that out when it was shipped to me so I am presently unable to confirm if it works. I'll eventually replace this with a newer style connector so that I can use a standard power cable but for now I an not able to confirm if these switches work or not.

Image
This initially looked to be keytronic reed, but they don't chirp and are tactile. The caps are all very solid.

Image
The back of the PCB is clearly not reeds, not enough pins on the PCB. The victor logo on the PCB leads me to believe this switch may have been produced by victor themselves.

Image
Image
Image
A shot of the switches from the side as well as a loose switch. They operate fairly simply with a moderate amount of parts in the switch itself, and a few additional related parts. Consisting of a top housing, bottom housing, slider, pusher, return spring, pusher spring, and dampening ring for the switch itself and a dampening sheet between the keycap and the mounting plate, rubber disk, spacer sheet, and PCB to round out the design. The slider pushes the peg against the rubber disk which depresses and bridges a contact on the PCB in the same way that a rubber dome switch would, just without any tactile action involved in pressing the rubber disk, then once the pusher has bottomed out the pusher compresses the pusher spring inside the slider to allow for over travel. An arm built into the slider is pushed against a ramp on the bottom housing which generates tactility.

Image
And here's the back of the machine. I have not yet disassembled the machine enough to locate any components with visible date codes, but the vintage-calculators.nl guess of '73 seems reasonable considering the style of components present. The switches and printer all very much feel like they are early 70s components. Once I have taken it apart and am able to get at the brains (which are underneath the printer mechanism) I will be able to get a better idea of when this thing was made.

User avatar
zrrion

12 Apr 2021, 12:51

Opened it up and got a good look at the internals:
Image
Bizarre printing mechanism.

Image
Very lovely PCB

Image
Big resistor and an LM311 with more pins than it should have. not sure what is up with that

Image
I'm not able to identify the logo on these off hand, but the bottom 4 digit number looks to be a date code, placing this at at least '75. Considering Monroe would launch their 1400 line in '75 using Alps spring bridge switches and Victor would later use SKCC switches as early as '79 so I feel that the date of '75 may be fairly late for this design. Unless Victor released the line that uses SKCC the same year that switch series launched then I feel like there would be at least some models that have spring bridge or possibly another switch between this tall membrane switch and SKCC. I have yet to find any documentation or any Victor machines produced between '75 and '79 to support this theory but it lines up with my current understanding of these early machines and early switches.
The 1800 line, launched in 1971 wash their first full line of electric calculators and I expect it to use the same switches as the 1900, especially since these switches appear to have been manufactured by Victor themselves. They did start adding electronics to their products by as early as 1967 but I am not sure to what extent machines produced during that time resembled the 1800 line. I would not be surprised if this switch was Victor's 2nd production switch but it would be equally unsurprised to learn that this was their first attempt at a discrete keyboard switch. If it is a first attempt they did a great job considering the vintage.
Last edited by zrrion on 12 Apr 2021, 13:13, edited 1 time in total.

User avatar
Muirium
µ

12 Apr 2021, 13:07

Those wavy traces in the last pic are a trip! A bit dirty to use as a DT header, but has potential.

User avatar
zrrion

12 Apr 2021, 22:20

I might clean it up a bit more and get another picture for header usage then. The thing is dirty and pretty heavy.

User avatar
zrrion

17 Apr 2021, 01:51

https://patents.google.com/patent/US399 ... r+keyboard

So I found the patent for this switch, which is apparently a "Detachably mounted keyboard pushbutton actuators and housing assembly." Which is a switch that uses as many unnecessary words for the name as it does for the operation. To quote the patent:
satisfies the "best feel" tactile responses desired in a keyboard,
which I think i a bit generous to call it "best feel" but the tactility is nice enough I suppose.

Post Reply

Return to “Gallery”