2. Output transistors Q600/601 are reversed or installed backwards.
That will cause the fuses to trip.. Found that out the hard way when I took out the fuse to troubleshoot! 
Ya, you're reverse biasing the transistors which will pull a ton of current. More than the 100mA fuse limit and they will trip. They are reset when you power cycle your rack.
One thing you can do to check is get your DMM then find a GND point on the PCB you can clip to. One of the sides of R303 or R301 for example. To determine which side is grounded, look for the side that has continuity to the GND pin. Then clip you back lead to that and clip your other lead to the leg of a fuse that is furthest from the edge card.
Now carefully slide it into the rack (you'll need an empty space to two to the right to let the DMM leads come out) and power your rack. Test each leg furthest from the edgecard. You should see a 16VDC, -16VDC, and 48VDC at the legs. If one or more is 0VDC that fuse is tripping.
Mike