1980 Cruise Control Sevo ?

[Porsche80]

OK, I think I have narrowed my CC problems down to the Servo. All electrical and ECU (brain) checks out including th clutch switch. In trying to troubleshoot the Servo I have tried the following
with the engine off of course
1. Disconnected the small vacuum line and used a small electric pump to see if it will hold pressure (seems to hold a couple of pounds). Does this sound right?
2. Disconnected the electrical connector to the Servo and applied 12 volts to it and you hear what sounds like a relay engaging.

In both of the above tests the throttle cable never moved

I reconnected all and started car and rev-ed up to 2k and engaged CC. It still did not work. Is there a certain speed or RPM at which the CC will work or does this indicate that my Servo is for sure bad?

Thanks and I hope others will gain from this as well.