Cool - all seems to work etc - it is (however) about 10 inches longer than the previous one.
My laser-cutter (a 60w 6040) has a craftily designed extension at one end to accommodate a longer tube... also craftily designed so that there's now a bare metal wall, about 1 inch from the anode, so it's arcing.
The laser seems to be firing (it burned the test tape), but arcing puts the fear of god into me, so I'm not doing anything else without getting advice etc.
So. Questions:
1) would you expect a laser-tube to do this?
2) if "yes", what ought I to do about it?
The things I have in mind for 2) are
a) insulate the anode... which is currently an alligator clip on a terminal
b) build a non-conducting (eg: acrylic) extension to replace the current metal one.
Answered your own questions. Yes, insulate the end that is arcing. You can do this by using a mass of silicone around the connection. I wrapped the bare wire around the insulation. The took a length of silicone tubing and placed it over the wire and the connections. I then filled this with silicone.