If the Main AC fuse is blowing, the control box is defective and needs to be replaced. The "Main Fuse" is a (5x20MM) 1 Amp Slow Blow fuse.
If the 12VAC fuse is blowing, verify they are not trying to power a strike or maglock form the operator as the 12 VAC output is only rated for at 0.25 Amp. The "12 volt "Low Voltage Fuse" is a (5x20MM) 1/4 Amp Fast Acting fuse.
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