Unless yours is very different from mine: the top cover comes off, the bottom cover comes off. This gives you access to just about everything. Is there some reason you need to get the front panel off?
Dave
KF7JAF
I recently upgraded a Viking II-CDC and the covers are as Dave KF7AF has stated. The top cover, as I recall, slides off backwards so you can gain access to the tubes and that is usually all that is needed to remove tubes to check them.
I usually bring up the voltage slowly on a Variac to 70Vac to see if tubes are faintly glowing and then to about 95Vac.
To get to the chassis circuitry underneath, yes the cabinet (shroud) needs to be removed.
You didn't state as to whether or not this transmitter has had its Power Supply components upgraded. If in doubt, replace them before increasing voltage and before any power output tests.
Phil