A bad driver transistor can cause an output to blow, also open resistors, etc. You said that you replaced the drivers, what did you use as replacements, 40409 and 40410's?
You can just pull the black connector plugs from the outputs and that will remove them from the circuit for testing. The red Collector wires can stay connected unless you need to remove the transistor from the chassis.
Be sure to leave the speaker disconnected from the amp until you can power it up without blowing fuses.