Thread by @TubeTimeUS

what have I gotten myself into? 😂

it's a paper tape punch!

only lightly damaged. at least from what I can tell so far.

the keypad looks familiar. i think it's something i can get an off the shelf replacement for.

haha stylish

continuing on the style theme

maybe I can fix this

scratching off some of the insulating layer

conductive silver paint applied.

lots and lots of microscopic breaks. but I think I got them all.

lots of dip switches! there's actually another dozen or so switches out of frame

it lights up, this is promising

the reader has issues. it's like one of the stepper motor phases isn't working.

likewise, the punch doesn't advance the feed. almost like that stepper motor has issues. more likely it's a problem with the driving circuit.

mostly fixed the reader. the stepper was out of phase with the photodiode inside that senses the feed holes in the tape.

adjusted that by very carefully fiddling with the set screw on the toothed wheel. do it with the stepper energized so the shaft stays put.

I suspect a similar issue with the punch. the feed stepper motor seems to sync up with pulses from this variable reluctance sensor driven by the punch motor

this little crank is on the other side of the variable reluctance wheel. it moves the pins in the punch up and down. the tape can only be advanced when the pins are down or you tear the paper!

huh, turns out the punch just works fine. I thought it was broken because I didn't see the sprocket rotating. now I should test and make sure it can punch a test pattern.

mostly ok! I should try it with the cover on and the spindle mounted correctly

can you tell what data is encoded on this length of old-school paper tape?

try this with your newfangled flash memory

for the text encoded on the punch tape, i needed to find an 8x8 font. i was going to draw one and then i remembered that I JUST RELEASED A GRAPHICS CARD WITH AN 8X8 font 😂

so yes, that's "Hello Twitter!" using the 8x8 font from the IBM CGA card.

so i'm borrowing the chad box from a friend because this didn't come with one. fortunately i have 3d modeling software, so now i have a model of the part. i'm thinking of sending it off for an SLA print in a clear resin, what do you think?

also inb4 hurr durr chad box 🙄

it also didn't come with the spindle, but i can easily print that at home. think i'll do it in 2 halves and then glue them together.

hot off the 3D printer

looks pretty close.

an SLA print in clear resin would have been expensive, so I decided to print it at home instead. about 10 hours to go 😐

and by "it" i mean a replacement chad bin. the original is transparent plastic so you can tell how full the bin is, but it's not hard to pull it out to check.

s l o w

finally it finished. the difference is pretty clear 😂

here's the design for the replacement spindle, if you need such a thing.
thingiverse.com/thing:4883102

and here is the design for the chad bin. if you're feeling adventurous, try printing it with transparent PLA. i hear it takes a lot of sanding afterwards!
thingiverse.com/thing:4883108