> When I unplug J3, disconnecting the regulator from the transistors, I get > a nice solid stable 28.5V from the LM317, and I can adjust it up or down. > As soon as I connect the regulator output to the transistor bases, I > measure 44.0V on the output of the LM317 and at the transistor bases. No > adjustment regardless of the pot setting. The collectors of Q1 & Q2 are > at 44.7V. This happens with or without a load on the emitters of Q1 & Q2 > - I used a 100 Ohm resistor for a test load. No appreciable difference > with or without it. The LM317 stays cool the whole time. Are you really really sure the pass transistors are wired correctly? It sure sounds like the 40V is being conducted right thru one of the junctions to the LM317. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.