To get to the axis bridge rectifiers: I remove the tape reader in the upper portion of the logic board cabinet. Just below the tape reader, there is a horizontal bank of capacitors. Remove the screws holding this entire unit. You may need to remove some of the wires from the terminal strip. As you pull this forward there is a black heat sink on the right side in the back of this rack. There are 4 VERY LONG screws holding this heat sink to the rack that will take forever to remove. The bridge rectifiers are on the inside of this heatsink. You will appreciate that you removed the tape reader if you have one there.