Hot end loosing temp

I have a taz 2, which is modified with all upgrades for the taz 5.

Recently I installed the hexagonal hot end. It was running great. I started printing at higher temperature (280-290) as a test.
I also was modifying the connector so that I could use my BUDA and hexagonal interchangeably.

I’m not sure if it was because I was running the nozzle and new high temperature, or if it was when i was modifying the V2 connector pins, but i’ve run into a problem now that I cant seem to fix for a couple weeks

My nozzle will get up to temperature (290 lets say) but when my part cooling fans turn on, the temperature immediately drops. I cant print with the fans on fast 40%, and even at 40% the highest temp it will go is 250.

So i’ve tried replacing the themosister, the heat cartridge and recently PID tuning. So far nothing has been able to solve this.

When i re-install my BUDA nozzle, and of course, reflash, the nozzle is able to keep temperature at 240 with the fan on.

When i manually stop the RIGHT side fan, the temperature begins to rise again. I cant re-position the fan because its the stop shroud.

I realize there is a “hot end not heating thread” but i was unable to find a solution there.

Any idea? Is my rambo too old to support the hexagonal hot end? Did i fry something? My Rambo has no signs of damage or burns.

I have the 24V 360W power supply.


Just a guess, but did you print out a new fan shroud for the Hexagon? It’s likely that the fan is blowing on the heater block and not down past the nozzle, if it’s blowing there, then it’s going to be pretty hard for it to keep hot as you are basically cooling it off.