If you have no secondaries at all, especially raw AC on
the main power transformer (some units have a second
cotrol transformer), the primary may be open, & it is NOT
infinity, it's low, but make sure the mechanical switch is on.
If the transformer is open primary, sometimes you can repair
it, even without opening it up, depending on which unit it is.
There may be an extra winding you could use. Hope this helps,
Rono.