Drained and refilled 93 Classic and it heats up fine. Jet pump control causes motor to hum but nothing else. It has frozen in the past and repair folks put a wrench somewhere to loosen up what apparently is a rusted motor. Any advice on what I can do to free up the motor?

Sounds like you have an air lock. Turn off the power, take the access door off and look for the biggest of any pumps inside. There will be a pipe going in, and a pipe going out. Locate the higher of the two pipe connections, and back off the union where the pipe connects to the pump until some water comes out, re-tighten and try the pump again.

If the pump is just humming and the shaft is not turning, you can take the back cover off the motor (where the wiring connects) and access the back of the motor shaft. It should either be slotted for a screwdriver or shaped for a 7/16" or 1/2" wrench. Give it a quarter turn or so and try the pump again. If it continues to not turn you may need to replace the motor.

Don't have a clue but will post anyway.

Our main Hot Springs pump is just under 14 yrs old and continues to work great but we realistically expect it to die sooner than later - our pool pump made it about 14 years before we had to buy a new one so if your Classic pump is still original from 93 you could be getting near time for a new one.

If the spa is otherwise in good shape the a replacement main pump will cost about $380 and a service call or no service call if you are a DIY kind of person. I DIY a lot of things but I have left spa component replacement to a experience service technician.

I would opt for having it replaced and suffer the consequences of enjoying our spa than trying to tinker around with it.