I have the Big and have only been using one print head, even tho I have the dual extruder.
I wanted to get used to the single before trying the dual.
While putting the parts together I noticed a lot of build up on the nozzle and underside of the heating block.
I decided to clean it before mounting it to the dual plate and SNAP there went the thermistor right at the block.
Half in and half out no fixing it.
So I decided to use the extruder I have not used and it is out of wack....
It wont regulate the temp, I had it set for 210 for the first test and it went up to 268 before I noticed.
Every time I try to heat it it just keeps going up, there is no stopping it until I kill the power........
So now I have no extruders that work!!
Went to Inventa Part, guess they dont have parts for sale yet.
Going to Ebay now.....