If you can set the circuit board on a clean, dry, insulated surface you can 'sort of' operate the monitor chassis. Some monitors (Hantarex in particular) will not operate without the yoke connected to the board.
CRITICAL SAFETY WARNING: If the board powers up you could have a live 20,000 volt high voltage lead flopping around which could
KILL you!

If possible and wire harness length allows, keep the HV lead connected to the tube for safety, but you can leave the neckboard off. No need to hook up the degausser coil for your board testing. You could try operating without the yoke connected on this chassis.