OK life slowed down enough for me to get back here...

Hi Sandy, and thanks for the information. The past few days
I've become pretty familiar with the inside of the Nuarc as I've
tried to get it adjusted as you'd suggested.

Nicholas, thanks for checking in on this. I have the 26-1K.
I'm happy to hear that you are so familiar with these integrators.
I just got it last week, and have had trouble with the light
flickering, then going out occasionally. The bulb looked old
and was quite blackened so I got a new one and installed it
last night. Then while trying to adjust the sensor early this
morning, the new light stopped working. ugh. I checked the
fuses, and one was blown. Tomorrow I have to try to find
new fuses for it ( I plan to just replace them both). Now I'm
wondering why the fuse blew, and if this thing really has some
serious problem. It's on it's own dedicated circuit that's getting
112 volts (I checked that at the receptacle), and the input
and output leads on the transformer are set correctly for that
voltage. I have learned way more about electricity and the inner
workings of this thing than I really want to know :o) I just want
to expose my plates and make some nice images.

So... Sunday I will try to get fuses and hope that fixes the bulb
situation, then maybe I can get back to calibrating it, and I
welcome help with that. Maybe the reason I had trouble getting
a repeatable result before was the old bulb.

Thanks... please stay tuned while I try to work through this the
next few days. I appreciate the help!