Seeing this thread pop back up again, I can now happily report that the mysterious trouble in opening my 8000T's casework has been solved: for some reason, the stamped steel cover on my example was epoxy-bonded to the top of the aluminum faceplate extrusion across the unit's entire width! I don't know if this could have been done at the factory or whether a previous owner must have been responsible, but it took a scary amount of effort and a leap of faith that I was prepared to break my tuner should I be wrong (I couldn't see what was going on until it was opened) in order to pry the damn thing off. The result was a separated but fairly bent top cover, but I was able to reflatten it out pretty well afterwards.
Fortunately, I found out the preceding before my unit's bulb has needed replacement. Thanks Dcb49 for the tutorial. It's interesting to note that a mega-tuner-comparo webpage I've forgotten the name of advised that the 8000T be left permanently powered-up for best sound, something I've never tried for fear of burning up the bulb even faster.
Fortunately, I found out the preceding before my unit's bulb has needed replacement. Thanks Dcb49 for the tutorial. It's interesting to note that a mega-tuner-comparo webpage I've forgotten the name of advised that the 8000T be left permanently powered-up for best sound, something I've never tried for fear of burning up the bulb even faster.