TIG'ing 6061 Aluminum??

[CGCINC]

I'm using 4043 filler.

I used to do really nice welds on Aluminum with my 250ex but the last three jobs I've done in Alum. has not worked so great.
Maybe the machine is at fault?!?!? I used to love this welder for Aluminum but it seems either I've lost the majic touch or something is not right...

[Mike J]

Did you try some test coupons with metals you know, and you confirmed no contaminants in your brushes or cleaners? You might have to experiment to isolate where the issue lies.