problem with marine air system...need help!

Hi.
You don't mention if the fans were actually rotating. Were any of them going?

The SMX boards can do some funny things some times. In the past I have had similar problems, maybe some stray voltage effected the board, I am not sure, But I found the programing manual and reset the board back to factory settings. Then the SMX board sent power to the fan unit. It was like resetting a computer.
You can find the manual on line if you do not have one. It is not complicated, just follow the instruction to get to the programing mode. Then you can also learn how to fine tune your unit. You might then appreciate having had this problem to really learn all the programing functions it has.

I am not sure what power leads you check (and I am thinking that you are referring to the fan units as the evaporators). The fan units will have more than one power lead for the water valve, fan and possibly heating elements.
I will be curious to know how you make out

The SMX panel on the wall will be connected to a control module box hidden some where very hard to find near the fan unit. The fan unit will then be wired from the control module. The control module is what sends the power to the fan unit. It is in that box where you can see if the fan is being sent power, although it does not necessarily mean the fan is receiving the power, as a wire could be broke or something un for seen.

If you take the cover off the control module box, you will see where the wires attach and they are labeled on the circuit board for what they do. You will see the wires labeled "Fan". Turn on the SMX board, make sure the set point is turned down for it to call for cooling, then you can see if voltage is being delivered to the fan from the box.

In the programing mode there is a parameter for split phase motor or shaded pole motors. If that parameter was changed some how for the wrong motor, you could have voltage still and the fan not running. I am sure you have a split phase motor. Just be aware of that one.

Howdy,
Also be aware that the "phone cord" style connector plus are pretty notorious for failing or making a "bad" connection on some of the pins. Check for this by wiggling the connector around, also spray a little electronics cleaner in there. Just a thought. Sometimes it is the very simplest thing that foils you!

What about a bad ground? if the power leads are hot, the ground could be shorted. I would check that. Also, un-hooking the wires/plug going into the SMX for about 30 seconds and plugging it back in usually gets them working sometimes.

Looking at picture #3, The green should be your ground. If you have 110V between the green and both other wires, then chances are good you have 220V being delivered to the fan, but you should still varify by measuring the voltage between the other two wires.
If the voltage is there then follow the wire right to the fan motor and make sure there is no breaks/damage and while at the motor, make sure it is a 220V motor. If it is a 110V then you know you burned it up by supplying 220V.
If the wire and voltage is all good, then disconnect the two power lead wires from the terminal block or go directing to the place the wires conects in the motor if possible (some motors you can, they have a small wire connection box on the side). Turn your meter to continuity and make sure you have continuity between the two wires going through the motor. If you do not see any continuity through the wires, more than likely your motor is toast. Yet you can maybe still get lucky and find something inside the motor that has come loose and then possibly repair it.
I always take apart an electric motor that has no continuity before I will condemn it for the trash can.
I will be looking fwd to knowing what the problem was.

There are to many possibilities to try and guess why you do not have 220V delivered to your fan motor, but at least you know why your motor is not coming on now.
You will just have to start at the control board and work your way to the fan motor. Where you see the one wire on the board labeled "fan", that is only half the voltage being sent. Find where the other half is coming from and start there.

Post the electrical schematic for the air handler. Plus any other interconnected systems, IE..... condenser & control wiring.

Also verify fan motor voltage from tag on motor. Your first picture showed a air handler that is duel voltage . Also many air handlers are rectifying the AC line voltage to DC current for variable speed fan motors.