The short answer is NO, never turn on your amp with no load connected to the OT (unless you want to purchase another OT). You could use a dummmy load instead of a speaker (a coil that dissipates the energy from the OT as heat instead of sound). You can find DIY dummy load coil projects in amp, radio and hifi chat rooms. But, you don’t need to turn the amp on to find the trouble. Using your meter, trace through the circuit, checking for grounds were there should not be one. First check the input jack.