My old Genie Pro 88 clicks and the light comes on but won't open--intermittent, sometimes works sometimes not. I see no adjustment screws anywhere on this thing.

These have had problems with the ground wire in unit making a good contact, reseating the ~20 pin ribbon cable, and I would also check the limit switches.

Tightened the ground wire... where are the limit switches? I can't find them anywhere! Thanks!

It looks like the part on the top right:
Genie Garage Door Opener Screw Drive Parts List (http://www.genie-garage-opener.com/screw-drive.html)

Of course! Sorry... I was thinking the up/down pressure switches which I still can't find on the thing. Not sure it has them!

I haven't been able to find a manual yet, follow all wires leaving the Operator.

http://www.geniecompany.com/docs/GENIE%20AC%20SCREW%20ENG.pdf
Look at page 6 on each end of the rail.
Does Part 15 a and 15 b look similar to yours?

The limit switches are similar. I will fool with those and see if there is any change. But interesting... look at Fig 7.2. I don't have those adjustment screws! I have seen them on every opener I have installed but no this Genie Pro 88... hmmm. Maybe I am getting blind in my old age but I see no adjustment screws... Mike

Look at page 27 for the open and close force adjustments, just below receiver terminals. May be like your model?

Yes. Clearly that manual is not for the Pro 88 I have. There are NO open close force adjustments below the receiver terminals--or anywhere else. The receiver block has five terminals, not four as shown in the 7.2 figure, two light bulb receptacles, an infrared jumper on the left to bypass the Safe-T-Beam when not used--that's it. I didn't know they made these devices without force adjustments! Mike