Hi guys I had a problem with the r271 blowing (yep cleaning the tip with power) on and so as per the fine information on this forum I did the repair as suggested. All went well and it started a demo print via the built in sample and it laid down the first layers then started cooling down (the extruder). So off with the cover and oops the inline fuse I added was popped so replaced it this morning, turned on the printer went to change filament (not cartridge)and it started to heat and then pop it blew that fuse. I've checked my soldering and nothing else was affected. Any idea what to check for? Until the extruder stopped I have had about 350hrs on it without any trouble. Oh yeah its running Da Vinci software and its the newer board (1.0a) and a reset empty cart in the slot.
Pete

Make sure the wires on the heater near it's body is not touching each other. Also make sure neither heater wire has exposed metal to metal contact anywhere along it's path from the board to the heater.