Revo Six Hotend replacing Hexagon Hotend

This is almost a perfect dropin replacement with only 2 issues I’ve encountered.

  1. Very Minor- The Revo 6 is 10mm longer, so you lose 10mm of Z and the zEndstop nob is soo loose as to be wobbly … fixable with a 10mm cap addewwd to the knob… easy fix.
  2. Killing problem: The hotend fan on it’s heater core is 24v instead of 5v like the hexagon was. So the PWM feed won’t run it… thus about 5-50 minutes in the filament suffers thermal runaway in the heatsink and clogs the entire thing up. Where can I connect a 24v hotend fan so that when the hotend is on the heatsink fan is too? The schematics do not make this very clear to me. I’ve tested the fan on 12v and 24v it’ll run off either, but not 5v it seems the Hexagon 5v fan was running using the PWM for E0 and Aux for E1 heatsink fans.
    Rambo 1.3l board.

Any suggestions?

Could you tell us a little bit more about your setup? What printer? Pictures?

For most (if not all) of the LulzBot printers, the tool head has two fan connections. One is for the cold end heatsink which is usually always on. The other is the part cooling fan which is variable speed controlled by M106. On my TAZ 6, both connections are to 5V fans.

I believe the fan you are talking about is the always on fan. If so, why not disconnect it from the Rambo board and just run 12v or 24v to the fan? I believe the current draw of the fan will be low enough that the existing wires should be able to handle it.

I believe a more sophisticated solution would be a relay or mosfet controlled by the existing Rambo connection. I’m not a hardware guy but I’m sure you can find a suitable circuit diagram on the internet.

yeah the diagrams were complicated enough and confusing enough to befuddle my EE coworker who designed his own engine control module. Someone elsewhere made the recommendation of obtaining a replacement 5v fan so I went and found one with nigh comparable CFM and static pressure ratings to the 24v… Seems to have worked so far.

oops… This is a TAZ 5 for the record.

I caved and bought a 5v fan to fit the Revo… problem seems to be resolved.

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