What can go wrong with the cutting heads used in those old record cutters? I read a post in another VK forum recently in which a member whose family owned a Wilcox-Gay "Recordio" radio/record cutter said the cartridge in the record cutter "burned out", and a replacement could not be found. Was that part something special, even when these units were new in the (I'm guessing) '30s-40s? What if anything can burn out in them that will render the record cutter unusable?
I'm guessing that cartridge had rather high voltage across it and was reasonably well insulated when it was new, but over time, as the insulation began to wear out and deteriorate, the voltage would arc across the cartridge's connection terminals (or even inside the cartridge itself), damaging the cartridge in an instant. Or did these cartridges just deteriorate on their own over time, to the point where the output of the cartridge, which I am guessing is crystal (not unlike the cheap crystal phonograph cartridges found in kids' phonos of the '50s), just dwindled down to zero or close to it?
BTW, I used the turntable and tone arm (the latter containing a cheap crystal pickup) from an old, beat up kids' phono from the 1950s-early sixties in a Part 15 AM radio station I had for a short time in the early 1970s, before I got my ham radio license. I removed the amplifier and connected the cartridge directly to one input of a 4-channel microphone mixer. It worked well as far as being able to drive the transmitter (a 3-tube Lafayette Radio KT195 "wireless broadcaster") well enough to be heard on the pipsqueak output signal, fed to a 10-foot length of wire in my basement. I doubt, however, if I'd have had nearly as good results had I used a turntable with a magnetic or other type of cartridge that ordinarily requires the use of a preamplifier stage ahead of it, to give the next stage enough signal to work with.