How to convert PS/2 and 5 pin keyboard to USB ?

[Evol]

Hi!

I'm getting into old keyboard reconditioning.
Cleaning them up is pretty easy and the information about the process is also easy to find.

But I have some issues finding how to convert those keyboard to USB to be ready to use.
I know there is some adapters available, but I would like built in solutions, with soldering if necessary.

I don't know if that request is quiet easy to respond, or if it depends on many parameters like which keyboard brand, etc.
In any cases, I'll be happy to have a sort of guide or method to do this.

Thank you

[fohat.digs]

A relatively simple way is to install "Teensy" breakout boards inside and program them with Soarer's firmware.

Actual instructions are back at the beginning of the thread. The good news is that most keyboards will work properly right away with no drama.

https://geekhack.org/index.php?topic=17458.msg2949400#msg2949400

[yui]

depending on how many hoops you are willing to go through and your budget you could go for a teensy with soarer's converter firmware but it is no longer supported for the longest time, you can also run it on a pro micro 5v if you want to go cheaper, although harder to work with.
an other option is Hasu's TMK converters, they are Opensource and Hasu is still supporting/developing them, runs on the same hardware and if you have experience with QMK/TMK you should feel right at home.
Although i like having the original cable and then a usb converters for my boards, i understand the appeal of having them "native" usb, i just like having the option to use them with the original machines

[Evol]

Hi !   

Thank you a lot for your help. 
I thought it would be easier to be honest, but doesn't seem that difficult neither.

Yeah I guess you're right @yui, maybe I'll consider just using a converter. I know that some gamers like to play with PS2 since it's more efficient than USB.
I have to try all those different methods and then pick the ones that fit with what I would like. 

Thank you again !

[yui]

well ps/2 converted to USB looses all its benefits, being nkey rollover and interrupts, the converter revert it to being a maximum 6kro polled keyboard. you need native PS/2 to have its benefits, although with the rise of 1khz and more polling rates that benefit is marginal at best.

[Leslieann]

Before you go building a converter try a simple passive adapter, there's a chance the board supports it.

[yui]

Before you go building a converter try a simple passive adapter, there's a chance the board supports it.

true in the case of PS/2, worth a shot especially if you own an adapter, although i saw somewhere that the pinout is not actually standardized for usb over PS/2, so it could be hit or miss (and in rather extremely stupid cases i suspect it could even damage the board, if a manufacturer was to swap polarity or meddle with the power lines in anyway that could be dangerous for very old boards, as is hot plugging)

[Leslieann]

I'm not sure how the wires could be swapped without breaking one or even or both standards and since they only control one side that would be pretty dumb. I'm not saying no one ever has, just that it would be extremely stupid and rare.

I'd be concerned if it was USB board converting to ps2 (I have a board like this) but not so much a ps2 board into usb, PS2 has higher amperage and usb has protection, In other words, it's not likely to do any damage. I've done it to lots of boards, they either work or don't.