After considering all the options I was offered, I concluded I could not justify the cost of sending my CP3 unit to AP to have the upper serial port repaired and have to deal with customs, etc, or purchasing a brand new CP4. Instead I found a good working condition CP2. My workflow is actually very simple, and when in the future I may require a much more sofisticaded mount, I will seriously consider a new one with all the bells & whistles.
I am happy with how the mount performs with the CP2.
I wanted to close this thread I left while trying to solve my problem, but in the spirit of trying to help, I found this: lots of "Communications Errors" between the control unit and the driver. This led me to substitute all hardware (cable, serial plugs, I even had the Keyspain serial/UBS reinstalled). My PC runs on W10 and is up to date. The driver I was using was Ray's last one. The "Communication Errors" did disappear when installing back the 5.09.01 driver (not that I tested all of them in between that one and the last one). But this is how I sar the "Communication Errors" disspear.
Thanks everyone for the assistance, my problem solved in an unexpected way, but I am happy I can enjoy the mount again.
Josep M. Aymami
Tiana (Barcelona, Spain)