My wife's Fender BXR-60 amp is in need of a new power cord. I'm pretty handy with this sort of thing, but I'm stumped as to how to get the back panel off to access the area where the cord is attached. I took the two screws off the sides that hold the panel in place, loosened the nuts holding the silver cover in place, as well as a couple other screws. The panel wiggles like it wants to come out, but in the end, it's still stuck. Thoughts? Thanks for the help!