Hi Eric,
Don't worry too much about lower voltages not being enough mate. I don't often use below about 7 or 8v on the var side. But I do wonder what would happen if I measure (if I ever get the var rail working
) a current when I have the load across + and -? Won't that be different with regards to the OPA's 0v? Wish I had learned more about OPA's when I could still learn! Doh!
As to the measurements, with a load of 150r which I work out at 100mA at 15v the readings from 0v are as follows.
Pin5=13.73v, pin6=13.73v, pin7=0.01v, pin8(supply)=17.6v
Still can't see an error in the circuit but there must be surely!
Al