The connection between the power supply and the head contains two 3/4 inch OD water lines, two about 3/4 inch OD power lines (one for the oscillator, one for the amp), and four thin lines (frame GND, 24V, security, and 220VAC). They are all stuffed into an about 3 inch diameter piece of zoof tubing.
I wanted to replace the water lines...
Remove everything from the zoof tubing, replace the water lines, make everything all nice and un-twisted then stuff everything back into the zoof tubing. The zoof tubing came off Real Easy (tm). This made me rather nervous, things which come apart easy never seem to go back together easy.
Everything was impressively tangled. Plan A was really doomed from the start. This also revealed that the insulation on the 220VAC line was cracked. So, time for a Home Despot run for some new cable.
So, now how to put everything back together:
First step: cable-tie the thin wires into a single bundle. So there are now five lines in the umbilical of approximately equal unruliness.
Second step: tape all the ends together, such that all the connectors don't hang out and catch on the insides of the zoof tubing. This required two attempts, the first one was still too wide.
Third step: stuff it into the zoof tubing. The power lines and tubing were rigid enough to go in. As I got further along, I would stretch the closed end, hold it down with my knee, and then work, the stretched part down the umbilical to the open end. It was actually easier than I expected.