Convert&Restoration project of IBM 3742 beamspring keyboard

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SneakyRobb
THINK

20 Nov 2019, 20:54

very impressive work!

Heikkonen

20 Nov 2019, 23:07

SneakyRobb wrote:
20 Nov 2019, 20:54
very impressive work!
Thanks Robb!

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SneakyRobb
THINK

22 Nov 2019, 01:36

I just noticed the angle on your stems is flat. The stems on mine are angled. Neat.
IMG_20191119_195051.jpg
IMG_20191119_195051.jpg (1.53 MiB) Viewed 234 times
*mine are like from this Orihalcon photo
beamspring side.jpg
beamspring side.jpg (45.01 KiB) Viewed 234 times

Heikkonen

24 Nov 2019, 19:05

So i had all the modules cleaned. Springs were evaporusted(left small layer to prevent further rusting),o-rings, and housings were ultrasonic washed and sliders were done with cotton stick,fly plates were left untouched.

Housings in their bath:
Image

Modules back together:
Image

I actually ended up assembling everything back together before adjusting stems but noticed that keypresses felt loose.I proceeded to press down the stems properly and got really great results.

https://streamable.com/ummom
https://streamable.com/t6864
(spacebar rattle that is present in the vid was fixed by placing few plastic sheets between stabilizer and the barrel so they wont move around)
Everything is now assembled and its time to go back to software side again. Restoration done.

Sneaky: Thats actually quite nice catch,in didnt even think of that before you pointed it out,i wonder where this difference comes from tho?

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SneakyRobb
THINK

28 Nov 2019, 16:52

Hi,

I am not sure why the stems are not as angled as other beamsprings. Perhaps due to the typing arrangement with the embedded desk keyboard they felt it not necessary to angle them. Other beamsprings are on-top of desks and much higher so it would make sense to angle the keys a bit. I am just speculating though.

As well you mentioned the PCB you are using has most but not all of the pads your original pcb has so you are missing 3 keys.

I have modified red's pcb so that the keys you are missing are present.

Because I imported a gerber into diptrace there could be slight formatting issues so, I will send the files to _red_ to look at/ask for his advice as well.

We will get those last 3 keys working!!


What i noticed about your 3 not working keys, they are missing pads. As well your enter key is overlapping, which is why you can still use it. Cool.

fix pads.JPG
fix pads.JPG (110.25 KiB) Viewed 119 times

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