Welcome!!! Do you have speakers or CD players or any input equipment still connected? Just wondering if you have tried both ways ( by itself and with speakers and input items) and it is doing the same thing?
Welcome to the site. I have the same setup. There are upgrades and lots of information about those 2 units. I like the amp and have had a few of them. I always like to keep one around. Enjoy!
Another resource that i used a lot because they always had what i needed is Simplyspeakers.com
And i think they were the ones that gave me the CD to use for centering. It worked great.
In my experience, I have not liked the outcome of my Re-foam job and pulled the surrounds off to do them again.
I don't see an issue doing it more than once or twice as long as the cone survives.
Good luck on the project!