Hi again,
Oh yes, that's right, now i remember. I've been working on a host of other electrical problems in between so im spreading a bit thin.
Anyway, yes, now i remember you posting that you tried plus and minus 2.5v and that is why i had said that the input common mode range was ok.
It wasnt about the 9v supply, but then i should have made that more clear anyway, which i dont think i did.
If it doesnt work with plus and minus 2.5v supplies (the +0.7v input that is) then something is really wrong. It should not work right with the minus power supply pin at 0v, but with that pin at minus 2.5 it should work ok. Since it doesnt, maybe the amplifier got damaged when you connected the 9v source (with no minus supply) and the input differential went too high for that op amp. That's my only guess, especially since you got the LM358 to work with no problems. The only other thing would be to make sure that the pinout is what you think it is, but i think you did that already.
So the thing to do now i guess is get another two or three of these op amps and try again, only this time make sure to use a minus supply, and also another idea would be to use a resistor say 10k in the feedback path rather than a short as in a normal voltage follower. That resistor may help protect the inputs if the output decides to go super high again, at least possibly.
The only other thing i can offer then is if you want to send me one of the op amps i'll test it myself with my own equipment, but it sounds like you got the tests right already.
Wait a minute...are you saying that you got it to work now with voltages above 0.7v with a 0v negative rail? If so then it sounds like it is working right?
Still, if you would like me to test one for you you could send me a chip and i'll test it and send it back, no prob.