
I found several sources for replacing the panels, and they are not terribly expensive (about$30 to $35 apiece). I was able to take apart the filter and find tears in two panels.
The hard part was figuring out how to put the interior panels back together. The grid, as it is called, is linked to a manifold, and it has to be put together just right. There are 8 panels all together, including one that is slightly undersized. Putting the panels back in place was a nightmare ... until I discovered the ONLY way to do it.
You have to turn the grid system upside down, with the manifold on the bottom, and then push the panels into place. The manifold has one bit of info; it tells you ONLY where the small undersized panel fits into place. After that, you have to snap the others into the manifold.
Any way, it worked out.
Hope this helps all of you might run into the same problem.