Help wiring an old HVAC blower to use as a shop fan

To me that looks like an ECM motor -- an "electronically commutated motor" or "brushless DC motor." This is a newer motor technology with a variety of benefits.. at the cost of being more complex. These motors can't run directly from a power source; they require a control system to operate. The good news is that yours appears to have that controller built into the motor.

Based on what I see in the wiring diagram I'd suggest keeping that PCB in the circuit too. It appears the PCB provides a convenient way of "programming" the controller's behavior -- things like how fast it should spin (implied the the choices of AC/HP size and AC/HP CFM adjust) and how soon it should come on and how long it should stay on (ON/OFF delay).

I've not had the pleasure (?) of working on one of these motors myself, but from what I can gather online (and considering there's no 230 V connection shown to your PCB), all those control signals are probably 24 V ac signals. It's possible you could have damaged the controller by connecting 120 V between pairs of black and white wires, but.. it's also possible the internal control was engineered to survive that kind of mistreatment. Though you probably could connect 24 V ac to some of the wires on plug 4 and get results, it seems much easier to keep and use the PCB.

Try feeding the motor and the transformer 230 V (or 240) on the black and yellow wires and put a jumper between the R and the G terminals. Be prepared to wait up to 30 seconds depending on how that ON/OFF delay setting works. If you get a response from the fan in these conditions you could experiment with the other programmable settings for CFM, delay, etc.