To help identify what control unit you have, there is usually an ink stamp number on the back or top of the case , & it will usually include an E, B ,or G. E is riv, B is lesabre/electra, & G is regal . I'm not sure what the other numbers are.
There are 2 bulbs inside that are replaceable, but the one was a special bulb that is discontinued, so you need to find one from a spare control. I don't know of any others repairs that can be done to the control.
As for the original question, converting to a manual system is a huge job. Better to get a service manual & figure out what the problem is,& do some junkyard searching for whatever parts you need.& keep the touch system working.