Texas Instruments TI-5040 Adding Machine
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SpacemanToby
- Location: North Carolina
- Main keyboard: Alps Typewriter Conversion
- Favorite switch: Alps SKCL Green
- DT Pro Member: -
Got this at a thrift store today because the keys felt mechanical. It is, kind of. It's like the whole keyboard is one big switch. There are 12 leads coming out the top that are soldered into the pcb. I'm assuming these are the 8 columns and 4 rows. The stems kind of look like cherries, but the caps are slightly too big to fit on a cherry stem. Anyway, I thought it was interesting and couldn't find much online about it. I'm not sure if I'm going to try and make anything from it. It would make a cool numpad though.
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green-squid
- Location: --
- Main keyboard: --
- Main mouse: --
- Favorite switch: --
- DT Pro Member: -
Looks like a cool calculator! Clean it up and turn it on!
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rich1051414
- Location: US
- Main keyboard: Whitefox Zealios 67g
- Main mouse: Logitech G900
- Favorite switch: Alps Orange
- DT Pro Member: -
I bet you could place foil tape over the keycap mounts and pop the foil mounting it on a cherry switch, and it would hold tight.
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SpacemanToby
- Location: North Carolina
- Main keyboard: Alps Typewriter Conversion
- Favorite switch: Alps SKCL Green
- DT Pro Member: -
Actually, I spent some more time with it tonight. The problem isn't the size of the cross mount, but that it won't fit down in the switch in order to press on. I took a stem out of a switch and it actually fits nicely.
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SpacemanToby
- Location: North Carolina
- Main keyboard: Alps Typewriter Conversion
- Favorite switch: Alps SKCL Green
- DT Pro Member: -
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green-squid
- Location: --
- Main keyboard: --
- Main mouse: --
- Favorite switch: --
- DT Pro Member: -
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polemon
- Location: Europe
- DT Pro Member: -
Power on using a ballast (regular 60W bulb in series with it is sufficient, check google for how to wire those up).
Check current draw, check if it draw a lot of current or abnormaly low. If you have an IR thermoter or even FLIR cam, check for hot spots, those are usually failed devices and/or shorts.
Check MOVs / resettable fuses and soldered-in fuses if they'r blown or damaged (they can break from dropping the device, etc.)
Try powering it up without the printer connected, sometimes a fault in those components causes the entire thing to appear dead.
Check current draw, check if it draw a lot of current or abnormaly low. If you have an IR thermoter or even FLIR cam, check for hot spots, those are usually failed devices and/or shorts.
Check MOVs / resettable fuses and soldered-in fuses if they'r blown or damaged (they can break from dropping the device, etc.)
Try powering it up without the printer connected, sometimes a fault in those components causes the entire thing to appear dead.
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BillyBuerger
- Location: WI, USA
- Main keyboard: Custom ortho/ergo
- Main mouse: Logitech m510 w/ Kailh silent
- DT Pro Member: -
Reviving a old topic here. I also recently picked up one of these old adding machines from Goodwill. I didn't know what it was but the keycaps looked nice at the very least and they felt like maybe some vintage linear switches in them. Here's an additional picture of the switch plate disassembled...
It seems to use a combined leaf springs per column which is pushed down by a slider with spring for each switch. Interesting design and it makes for a decent feel. Similar to Fujitsu leaf spring, there is only really a downward push and no cam for a sideways leaf to register. So it feels pretty smooth. I'm not sure though where the actuation point is. I took it apart first so things probably aren't as tight as they should be. It does appear to register before bottoming out but it does feel near the bottom with little travel after actuation.
Like many old switches/keycaps, the stem is completely external so the keycap is filled with no room for the keycap to surround the switch like modern switches do. It does appear that the keycaps use the same thickness on the cross mount so an MX stem could fit well with the switch. MX keycaps do not fit on the switches though as the cross is larger in diameter. If I decide to use these keycaps in something, it would likely be with Choc switches using an adapter to MX mount which would sit completely above the switch. The choc switches help keep the overall height to be more normal with the extra height needed for the adapter.
The power cable was already cut off on this one. I will probably try to wire up a new one just to see if it works as is. I would mostly likely use the keycaps for something else if anything. But it would be a fun project to keep the overall machine looking as is but wiring it up with a custom PCB and QMK that can connect to a PC as a numpad+macros or something.
- TI-5040-Switches.jpg (1.52 MiB) Viewed 1630 times
Like many old switches/keycaps, the stem is completely external so the keycap is filled with no room for the keycap to surround the switch like modern switches do. It does appear that the keycaps use the same thickness on the cross mount so an MX stem could fit well with the switch. MX keycaps do not fit on the switches though as the cross is larger in diameter. If I decide to use these keycaps in something, it would likely be with Choc switches using an adapter to MX mount which would sit completely above the switch. The choc switches help keep the overall height to be more normal with the extra height needed for the adapter.
The power cable was already cut off on this one. I will probably try to wire up a new one just to see if it works as is. I would mostly likely use the keycaps for something else if anything. But it would be a fun project to keep the overall machine looking as is but wiring it up with a custom PCB and QMK that can connect to a PC as a numpad+macros or something.