Ultrasonic cleaner refurbishment

[powerdoc]

I have a Crest ultrasonic with separate generator and tank.  I purchased it used a few years ago and now want to use it.  It appears to have a problem with the coax cord which is damaged outside the tank and also appears to have been repaired internally inside the tank assembly, although for the life of me, I can't see how that might have have become damaged, but I digress. The ultrasonic transducers themselves show no defect in connection to the tank or discoloration from over heating.  What type of coax is generally used (before you ask, I already called Crest and their answer, of course, was to send it to them for repair) for ultrasonic generators with a BNC connector?  Also, can I test the generator by just hooking it up to my scope and checking for a waveform?  Many thanks, in advance, for any helpful information.