In that era of Otis elevator there are many different versions of controllers I have information on.
The 3F, 3FA, 3FD, HK, HKB are DC resistance controllers
The 21ANS, 21ANAS 31ANS and 31ANAS AC/DC controllers which may have come with a 11NAM or 11ANAM micro controller
And the list goes on!
As JohnJay said “what is the number of the controller?”
If you would like send me a PM, I would be glad to speak with a mechanic from your elevator service Company.