TIG Welding Problems

[cobrawanabe1699]

Hey everyone, I have a question for you...

First, here's the background....
-The welder in question is a brand-spankin' new Miller Syncrowave 200
-I know (as I have checked the entire gas delivery system) that the argon is making it to the gun
-I am attempting to weld 6061-T6 aluminum in DCEN (direct current electrode negative)
-I am using 7" long, pure tungsten electrodes (green band) in 3/32 dia.
-The gun (electrode holder and gas/electical line) is a Weldcraft (can't remember the model)
-I have the ground clamp postioned as close as possible to my workpiece, which is on a steel bench.
-I have tried to clean the elecrode in AC, but the problem persists...

Here's the problem...

In order to get a puddle, I have to strike an arc on the metal. But with this machine (I have used the same model before), that should not be necessary. As soon as the electrode gets within 1/4 to 1/8 of an inch of the metal, the arc should show up, no matter how much I'm on the pedal. By striking the arc, I am in turn contaminating the elctrode, and ruining the weld before I have even formed a puddle. The puddle does not appear shiny, and the electrode ends up black, without a properly balled tip. I have checked my settings time and time again, and have practically memorized all the literature that was shipped with the machine. I have also read the welding process books at my school almost religiously for the last three years, and am a pretty experienced TIG welder for my short 17 years, especially with 6061 aluminum.

Is it me or the machine? What in the world am I doing wrong? I think it may possibly be a current problem with the machine, as a group of my colleagues set up the machine without my supervision.

Thank you so much for your help!