I have a Troyke U12PNC CNC rotary table. It has no control
attached. It represents a vertical/horizontal mount table, and instead
of a handle like on manual tables, it has what looks like a DC servo.

It has the following wires:

1) Large BLACK and RED
2) One three conductor cable with Blue, Red and Black wire. I am
guessing it is a tachometer
3) One multiconductor cable with a few small conductors, if I could
guess it is the encoder.

I loosened its locknut.

I tried connecting the thick BLACK and RED wires to a DC power
supply.

The table does not move. The current goes to 5A (the limit of this
power supply) and the voltage would not go above 11 volts, IIRC.

There are four holes for brushes. Very oddly, they are covered or
sealed with some kind of goo, like silicon glue.

Would anyone have any guess as to what is wrong.

My own explanation is that the table is either seized, or the motor is
somehow shorted.

i