Looking for Eastar 430-0002 transformer. Anyone point me in the right
direction?

Probably only available from the manufacturer or their priority
supplier.
APC probably will not sell you replacement parts.

The only other source I could think of would be to find a 'donor'
unit. Are you sure the transformer is bad, though? They don't die very
often.

The power lines feeding our shop is notorious for crappy power. The
transformer that appears to supply the voltage to run the control board is
the one that is fried. The 120V side coil(s) is (are) open.