Need to repair IBM USB ThinkPad keyboard

[ThinkPad560X]

I have my favorite IBM ThinkPad travel USB keyboard Model SK-8835 and the NUMpad Enter and + key isn't working. I use this keyboard daily on my ThinkCentre desktop. I even took the keys off and cleaned under them and even took the keyboard apart and the NUMpad is a separate keypad with a ribbon cable going to the main keyboard board. I unplugged it and replugged that in as well. I tested two different machines to see if it was the desktop I use it on and even reinstalled the keyboard driver. The 2 keys are unresponsive. I want to be able to fix these keys. A replacement is $599 and probably will go up in value as these become harder to find. I use the NUMpad daily when I am using calculator and such. I looked to see if the W700 would work but it has a different ribbon cable.
https://www.ebay.com/itm/335071267517?h ... R6aEruOFYw