How sensitive to heat are these units? I just replaced the two computer fans behind the DBR resistor because they weren't working.
I also just got the HHT. I work for an independent company so it took a while for me to get a hold of it. It is actually one of the simpler tools I have used. Only down side was that I could view all of the parameter but as soon as I hit "UPD" it just sent me back to the beginning of the menu. I assume this is some sort of proprietary lock out or something.
A more experienced friend of mine told me that those power supplies are ridiculously sensitive. I will have to check that. Is there anything you can do about voltage dips? Is there a trimpot or something that can pump up the volts?