diagnosing transistor failure in H bridge
If you want a better bridge , use complementary power darlington emitter followers inside Op amp feedback loop on each side but invert the other side. Then use 12V to drive 24V-4 * 0.65V if using CMOS Op Amp to drive 10ma*hfe^2 but watch out for resonance with long leads.
Shootthru will not occur with this.