I've just been out welding, and suddenly my welder stopped working. It's still got the cooling fan running, and the wire is still being pushed out (and gas flows). But it's not striking, almost like the earth is no good. I've tested from the connecting posts inside the welder for continuity, both the earth clamp and the gun are connected back to the posts. I've opened it up and can't see anything obvious. The relay at the top of the machine still clicks when I pull the trigger. It doesn't strike on any power setting. I've even tried touching the wire to the earth post inside the welder to completely discount the earth clamp, still nothing. Is there anything I can look for? It's one of the Aldi welders, manufacturer date of 2009 apparently but it's been find up until now.