Ender 2 troubleshooting
My attempts to follow this up with the seller turned into a wrangle with them wanting me to contact Creality for support and I ran out of enthusiasm as I was busy and I had fixed the other printer. I just never take my own advice about not accepting repairs on new goods instead of demanding a replacement. One day I'll learn.
This weekend is quiet so I pulled it out and had the cover off the controller. It's a really easy printer to work on, just undo the three outer screws on the cover and it pops off giving you easy access to the board. I know it's never actually worked but I'm still impressed with how nicely this is put together for the money.
As I suspected, with the hot end heater cartridge disconnected the printer no longer cuts out when you apply power to the hot end. The heater cartridge isn't a dead short, but it's only about 2 Ohms.
To test things further I connected a 35W incandescent 12V light bulb to the heater terminals and everything works fine, so the board and PSU are almost certainly good.
I've now got a replacement hot end on the way, thankfully parts for these are dead cheap. You can get better quality upgrade parts for the Creality printers but when a good hot end is as expensive as the whole printer I'm unconvinced of the worth of this. Everything I've seen from other owners is that the stock hot end is perfectly adequate.