- 4' of 22 gauge wire - black
- one 2 prong electrical connector - there should be an extra in the RAMBo connector bag that came with your V3 - see photo below
- a few minutes of time
Disconnect the Bowden from both the extruder and hotend. Don't loose the little lobster claws! Now pass the 4' of wire INSIDE the Bowden from the extruder end until it comes out the bottom. Grab the wire at the top and then pull the Bowden out of the whip sleeve from the bottom near the hot end. Yes, you are removing the Bowden from the sleeve. This is all to make sure the thin black wire is inside the whip sleeve. If you come up with an easier way, chime in! Once the Bowden is removed, you have to put it back in exactly the way it came out (except without the wire inside it!). When you are done, you'll have the wire and Bowden inside the whip with the wire coming out of the side of the sleeve at the top like this:
Next, unscrew the bulkhead connector that the sleeve and wires run through in the top plate. Also remove the top access plate.
You need to loosen it all the way in order to get the wire through the fitting. Carefully find where the wire comes through the sleeve braid and push the end back through the same opening and up towards the top. The idea is you want to get this last foot or so of wire inside the sleeve, through the fitting and out of the end of the sleeve in the top. It is much harder to describe than it is to do! Once the free end is visible in the top, grab it and pull out some of the slack but make sure NOT to pull the lower end up into to the sleeve.
Now we are going to remove the connector and top cover from the HE280. Inside looks like this:
The arrow points to the connector for the heatsink fan. Clip the black wire about 2" from the connector. Then strip and solder the other end to the new black wire. Make sure to put on a piece of heatshrink tubing before soldering. There will be a short (2") black wire hanging free off the connector, that's correct. I like to put a little piece of shrink tube over the end to insulate it.
Now we are going to make the connection to RAMBo. The new black wire inserts into the connector like this:
The connector fits into the top edge of the RAMBo at the position marked Heat 1 - NOT Fan 1, like this:
That's it! Before buttoning everything up, test to make sure the fan comes on at 40°. You will need to plug in the HE280 connector and then turn on the printer. Then set the hotend temperature (LCD display is easiest) to 150°C (the minimum it lets you set). Watch and listen. If the fan comes on at 40° turn the hot end off and turn off the printer.
Now you can reattach the bulkhead fitting. Reinstall the HE280 cap, making sure to route the new wire so it does not interfere. Connect the connector to the HE280. Finally, connect the Bowden at both ends. Make sure to seat it all the way into both the extruder and the hotend. Here's a trick, after you insert the little lobster claw under the locking ring, push the tube in firmly, it should insert another mm or so. This insures that it is properly seated all the way. Here's the hotend completed: