[eccerr0r]

it is most definitely generating heat when both are turned on... Not a dead short but most definitely is drawing power that way. Crossover dissipation to an extreme.

It would just be the rectifier diodes on the power supply that'd die if it was a true short. Which very well may happen if the transistors meltdown... but do they? It'd have to leak a lot to generate that much heat I'd think.

Let's say you have 100mA crossover, at 100V across. That'd only be 10W (actually 5W per) which should be very doable if your transistors are well heatsinked. I'd say you'd need near 300+mA crossover to start getting worrysome, and how much component drifting would be needed to get that when the setpoint was 20mA to begin with?