UPDATE to the post below.
I finally got my printer working. Ran an initial fill after priming the dampers and cleaning up seemingly endless ink drips I got everything buttoned down and finally working. I think part of the problem was that I had the damper fittings screwed down a little too tight and that seemed to stop the ink flow. On the other hand, too loose and you get leaks. Has to be just right, it seems. This has all been a learning experience, I guess.
I'm starting to wonder if I'm going to get my printer working again. I replaced all the dampers with ones from InkJet Mall and also replaced the Flush Box and put in a new pump and capping station assembly. After putting everything back together and running power cleans, I tried a nozzle check and found that there is no ink coming out at all. Before this, my 7800 was printing very well.
Today, I took the damper assembly off and primed the dampers to make sure I could get flow into them. I put everything back together and there is nothing printing at all. Everything sounds normal to me. I'm starting to get very concerned. Any ideas would be welcome.