Logan
Read my thread on the Kendrick.
http://www.iceinspace.com.au/forum/s...ad.php?t=57962
I'm not impressed by them, but I got the one I have working. The 555 IC had blown up in mine - sounds like you have the same problem. That resulted in max volts out at all settings of the control knob.
So your heaters should have been running flat out and quite warm to touch, if yours is behaving that way.
Woops! I just looked at your photo. Brown is under the driver transister/FET. Must have been overheating? But I would still suspect the 555 (as well?)
Have you checked the resistances of your heaters? Have they "blown"?