After fitting the large output transformers to the panel, the next step was to wire them up. First you need to wire the links on both the primary and secondary windings to set the correct ratio (2:1 in this case). Two links are required on the primary as the two windings are wired in parallel. They are the red and black wires shown on the picture below. The secondary needs only a single link to wire the two windings in series. This was done with yellow wire. The primary sides are connected to unbalanced amplifier outputs so these need a single core screened cable terminated in a two pole Molex KK connector to plug into the backplane PCB. These are the grey cables you can see.The secondaries are balanced and use a twin core screened cable (black cables). Only the hot and cold are connected to the transformer. The screen is not connected at the transformer end but only at the XLR end. The XLRs are not connected yet. They will be connected after the panel has been mounted in the mixer.
The four cable pairs on the right are the the direct outs of the four channel amps. The four on the left are the master bus L/R and AUX1/2 send bus outputs which come from the two Twin Line Amps fitted next to the four channel modules.
I have a simple convention I use to identify the hot and cold wires in the Van Damme twin screened cable I use. The two wires have white and blue insulation so I make the white hot and the blue cold for obvious reasons.