Sorry but I don't have any other commands for you to try. The Robo uses Marlin firmware, and the Marlin documentation says to use E-1.

http://marlinfw.org/docs/gcode/M303.html

Maybe the Robo is on an old version of Marlin that didn't have this feature yet.

There's really not a whole lot to troubleshoot. Either it fits or it doesn't, and if it doesn't you need to figure out which part is too big or too small. It could be a poorly machined part on either side, though it's hard to imagine either one making a machining error that would result in such a difference.

That is correct. The thermistor can only safely go up to 295, but the rest of the hot end is capable of going much higher. If you want to print at higher temperatures, consider installing a thermocouple instead.

These instructions are for MatterControl version 1.5.3 and previous. For 1.6:

1. Follow these instructions until you get to the 'Edit printer settings' step: http://wiki.mattercontrol.com/Custom_Pri...

2. Instead of editing settings, load the .ini file included in the download from this guide.

3. Continue with the other guide starting at the 'Export Printer Profile' step: http://wiki.mattercontrol.com/Custom_Pri...

4. Once you complete that guide, insert the .printer file into the .../MatterControl/StaticData/Profiles/$Manufacturer$/ and restart MatterControl.

You should now see the new printer profile in the drop down menu.

Ah yes, I forgot about the 5V micro-blower fan-- it's been a while since I tinkered with the TAZ. Thanks for your input!

Thanks, Matthew; good catch! The link has been updated.

What's the advantage of 5V? I've seen RAMBo boards have trouble supplying enough power to heat sink fans and heat creep occurs, so I just wonder why you chose 5V instead of 12V.