macona wrote:The trimpots will have nothing to do with 120c vs 240v input. They are most likely pots to control frequency and duty cycle of the PWM IC that drives the power transistors.
Not impossible that they built a controller to tolerate that much variation in the DC input to the inverter. However having looked more closely at the large caps...
The switching is done on the power input side. It changes the input from a direct input for 240 to a voltage doubler for 120v input. Might be something on the back side of the PCB.
The only large rectifier on the board is the full bridge in the lower left of the last picture, obviously followed by those two 680uF 200V (!) electrolytic caps. There's no room for a doubler on the input. Perhaps the 220V version is using a half-bridge instead? Different component(s) there or only using half the rectifier. The only wire I see on the bottom of the board (without removing it) is in that vicinity, but there is a silkscreen for the rectifier labelled "BRG" so the 110 version seems to be the "natural" version. I look forward to pics of the 220V one.