Now, while those are out, check all emitter resistors, the big, light brown ones, one per output... Should be .33 ohms, your meter may not measure sub ohm accurately, but that's Ok, we're looking to make sure they are not open or shorted...
What we did there was eliminate any other short that might be present. Good news there bud.
Collateral damage can occur on the board with a blown output. a LOT LESS chance with the WO boards but it can happen. Bless you for not keep putting in fuses after the first blow, that can cause additional problems.
So, do the BE,BC, Ec checks on the TO-220 pre-driver trannies on the bottom of the right side of the board, you'll get some weird readings on the reverse tests but we're looking for shorts or opens is all, in diode mode. Base on those 220's is left pin when pins are down and writing is toward you..