Recently I bough a faulty Wanhao Duplicator 4S to increase the capacity of my 3D printing requirements as I already own one and know the machine inside out. eBay seller’s description wrote that the 3D printer stalled in the middle of a print. I did some digging across the internet before I purchased the machine and was suspecting that some wires were not shielded correctly which resulted in electromagnetic interference. It cost me £300 and that’s half of the retail price so even if I couldn’t be able to fix it, I would have plenty of spare parts for my current 3D printer.