Convert&Restoration project of IBM 3742 beamspring keyboard

[SneakyRobb]

very impressive work!

[Heikkonen]

very impressive work!

Thanks Robb!

[SneakyRobb]

I just noticed the angle on your stems is flat. The stems on mine are angled. Neat.

IMG_20191119_195051.jpg (1.53 MiB) Viewed 1136 times

*mine are like from this Orihalcon photo

beamspring side.jpg (45.01 KiB) Viewed 1136 times

[Heikkonen]

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:


Modules back together:


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?

[SneakyRobb]

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 (110.25 KiB) Viewed 1021 times

[Heikkonen]

Its been awhile since i have updated this thread. Since then i have managed to create a layout and get the layers working along with more testing to see if i see any odd behaviour from the kb(did few hours test run). I have now managed to get into state where everything is working as intended.

This is a good moment to appreciate members of the community that have provided me alot of information and have stayed up late hours answering my dumb questions.

Special mentions goes to kmov2017(You truly have nerves of saint what comes down answering and detailing everything,without you this kb would still be a display piece,big one to you)
Sneakyrobb(You are genuine guy who offered to help me with not even asking anything in favour,your passion is respectful)
DMA(Without your great efforts making an update to commonsense,i would be still fighting with threshold values with no clue that i cannot never get them to fully work)
JP!(You were the one who i first contacted and you told me alot of valuable information regarding this specific model. The moment you told me this thing would be convertable i was down for it)
manisteinn(Lasercutting the foam and i didnt even ask for it,genuine and hard working guy in forums,not just with this specific deed)
__red__(Making the pcb that im currectly running)

Heres a something i wanna say to you all:
https://streamable.com/7l1yy


I most likely do a table for it in the future along with getting last 3 keys to work.

To be continued.

[tron]

Great job with your restoration. The foam looks like a close match to the type I found in my RPQ Cyrillic 3278. It wasn't the degrading tar like foam but rather some type of rebond. I chose to remove it because of the musky smell but otherwise it was in perfect condition.

[pansku]

Nice to see another beamer spring back to life! Especially when they are so scarse at these latitudes

[Heikkonen]

Great job with your restoration. The foam looks like a close match to the type I found in my RPQ Cyrillic 3278. It wasn't the degrading tar like foam but rather some type of rebond. I chose to remove it because of the musky smell but otherwise it was in perfect condition.

Thanks tron! I truly needed to replace the foam since it was tar like substance you mentioned there(smell wasnt the best aswell ) , also New foam prevents wobbling and modules fit tightly

Nice to see another beamer spring back to life! Especially when they are so scarse at these latitudes

Im happy that i was able to restore and convert it without breaking any of the modules, even they were relatively clean pulling off the stem is always a moment where you question the method you are using. I was little bit too gentle with reassembling(pushing the stem back into white slider part) and keyfeel wasnt the greatest,i actually ended up adjusting the stems like 3 times before i was happy with the results.

[pansku]

I still remember the tension in the air when I pulled the first stem out with my knuckles almost turning white

[Brett MacK]

I know i'm late to the party here, but wonderful restoration, I feel most of the built in beamers don't get the restoration they deserve.