TAZ6 screen is blank. ON-OFF power switch is lit. I’m stumped and stuck. Can someone assist please? Machine has been working well up to now.
It sounds like you will want to check the fuses on the Rambo board. I have attached a photo of the locations of all three fuses.
RAMBo has 3 user replaceable fuses. The small white fuse holders are Little Fuse OMNI-BLOCK fuse holders. They are compatible with NANO2 Fuses. Fast or very fast acting are recommended. An example part number for replacement fuses is 0448005.MR
F2 supplies the motors and on-board power supply.
F3 supplies the extruder heater + fan outputs and logic.
F4 is a 15A ATO (the type found in many automotives). F4 supplies the heated bed output.
5 Amp Nano Polyfuse (x3): https://www.lulzbot.com/store/parts/5-amp-nano-polyfuse-x3
Thank you for your help. Yes it was the F3 fuse. New one(s) on order. Thanks for pointing me in the right direction.
PS. I did not know they made replaceable fuses that small. 
Yes but what caused the fuse to blow?
I’m in the same situation now, F3 fuse blew. Looks like I created a short somewhere on the hot end while trying to tighten up the hexagon block a bit trying to fix a leak coming out of the top of the heat block. These fuses are special order, I hope I fixed the short. Don’t want to get these fuses plug it in and have it instantly blow again. Don’t want that to happen to you either pops! Glad I had a pair of hemostats around else I don’t know how I would’ve gotten that fuse out. The included tweezers were to flimsy to grasp and pull.
The main thing that we see that causes the fuse to blow, is if something metallic or conductive comes into contact with the nozzle. It can create a short back to the RAMBo board and that fuse will usually blow, before taking out the RAMBo board itself.
In my case I had the bright idea of cleaning the outside of the nozzle with a small brass bristle brush.
Live and learn…