FOT does not have replacement inverters. I purchased mine from luminousfilm.com
DC-12V, Inverter for Parallel Electrode Panel, (300-600in2)
Inverter for Parallel Electrode Panel, Input Voltage 12VDC @ 2AMP, Output Voltage 100VAC @ 600Hz, Size – 6.125 x 2.375 x 1.75-inches, Weight – 32oz, Capacity – 300 to 600 square inches of panel, Color – Black,
Made in the USA. VAC to VDC Power Supply Not included. SKU Number: IN2005 Price: – $97.50 Bob Rozek 1997 U320 40′ 9/6/13