In that link, Dave says:

"It appears that to save money, that this option was removed from the last few games that they made. The adjustable transformer last appeared on Zankor. Spooky, Stars Phoenix, and New Stars Phoenix came with a 220V only transformer, with no adjustment selector, and not even a 110V tap."

The picture posted above by the OP clearly has taps on the transformer for other AC mains voltages.

I would give it a shot.
To test, remove the 20amp G.I F2 fuse and disconnect CN1 from the Power board so nothing is connected on the output of the transformer. Measure the AC voltages at the CN1 wire connector to confirm they are still in spec with reference to the Spooky schematics.