I have tried to clean and mod two Dell AT102W keyboard (found in the trash) both seemed to be working when a got them bot now they are both dead

. I changed the switches in one of them to Matias tactile and started to test it out some with a cheap ps/2 to usb converter on my Macbook Air and on my PC. It started to have strange behavior like random character thrown in while typing or key stroke randomly starting to repeat without me even touching the keyboard. So I opened it up again and looked throw all the soldering and cleaned the PCB once more. Still problems so I swapped the controllers between boards and tried again and it worked!... for a little while than I put it in the Macbook Air with the
cheap converter and now it's dead too ...

. I have tried to replace the capacitors since then but that didn't help. I think this combination of hardware is the problem but it could also be me killing the controller with ESD. I have used the same converter with a Model M in the pc and that has been working fine but now I'm scared that the converter is dangerous.
Have anyone else had the same kind of problem? Advice or theories about how to not break old ps/2 keyboard when plugging them in to USB. Recommendations or warnings of converters. And have anyone got a spare Silitek controller? (I'll check the part number to night)
EDIT: the Silitek controller has part number: kkmpa80604