General Radio Variac W5MT3 trasformatore automatico variabile trasformatore di potenza testato

Tested and works. The light bulb comes on about 90 (volts?). I didn’t have an incandescent bulb to test it which might have worked better, but it does get brighter as you turn it up. The red light on top turns on and off with the switch. The knob seems to have the right amount of resistance. The switch clicks firmly. There are some aftermarket screws in the top. It seems most of these are modified in some way, so it doesn’t seem out of the ordinary

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