Well, the STi went to SBig, where they found it is just fine. Something else is wrong. I will have to try some different cables? Ports?
I implemented the 3 port expansion plug for the autoguider cables. Found a 6 conductor phone jack extender which has one male plug that goes into the mount autoguider port, and has 3 female jacks. Each of the cameras (ST2000XM, STF8300M, and STi) can be plugged into the jacks at the same time. Now, when I want to switch guider cameras I do not have to go out and reconnect the guider cables.