Here's what I found on this forum when I replaced my TV in our '05 Dolphin"
"I keep getting questions about how to get the front overhead tube-type TV out of a National RV. This pertains to a 2005 Dolphin, but probably is similar for near model years since National probably adopted one set of fixtures for several models.
The TV is hung from the overhead framework by a steel cage that has a removable bottom tray. The trick is to get to the cage.
The front wood trim, or fascia, is a single piece that needs to come off. There is one screw in the top center fascia piece that screws into the ceiling. Remove that.
Remove any putty caulk that is between the fascia and the side cabinets.
Open the side cabinet doors, and you will see two hole plugs that cover recessed screws that screw in from the side cabinet trim frame sideways into the fascia (two each side). Remove the plugs and then the screws.
The fascia should now be loose and can be pulled forward at the bottom and dropped down from a slot in the ceiling.
Now the steel cage will be exposed.
Remove the plastic panel that is under the TV (above the dash).
Reach in the back to unscrew the antenna connection from the TV.
Unplug the TV from the power outlet in the upper right equipment cabinet and pull the wire plug free into the space behind the TV.
There are three bolts on each side of the bottom of the cage holding the bottom tray on. The clearance is tight but the bolts can be accessed. Loosen the two nearest the windshield (rear of TV).
Remove the center two bolts and one front bolt. Now get help and remove the other front bolt.
The TV needs to drop down at its front, and then is lifted off the tray.
It is 100# plus, so plan accordingly.
This is the info provided directly from a NRV tech before they went under. Good luck."
J.J. Hayden (KN4SH)
2005 National Dolphin 5342