The smoke test did not produce actual smoke, but the current drawn is close to 1A. Considering the transverter should be in receive mode, that's not normal. Leaving it on a few seconds the Mitsubishi PA final warms up, so it is probably self-oscillating somewhere.
I have never troubleshoot a self-oscillating PA, just quickly read about it. I am thinking of two causes: either the DC supply cord is too long and lacks decoupling or the transverter board is too close to the box/ground.
