A schematic would be handy.
Output transistors are paralleled so a short in one means they will all measure shorted on that side with a DMM, or near-shorted due to the fractional ohm emitter resistors. A shorted transistor can take out one or more driver components depending how it fails. I power up a fuse-blower with no load connected (a bulb limiter is handy if you don't have a variac) and monitor the output voltage at the speaker output. If I'm seeing the amp with a hard + or - DC voltage it's usually the output transistors on one side. If no DC either its shorting rail-to-rail or a PSU issue.