If its in the power supply board take lots of pictures to get it back together because Lou, you and I know what a pain that is to get to. The only one I have done took 4-5 hours of disassemble time just to get to it. I guess they were not thinking on it ever having a problem and all that to replace the HV diodes because one opened up and change out the meter resistors because they had changed values and the meter was not reading HV correctly. If that is the case I would cut a hole in the bottom and cover it with a plate so the next time you will not spend all your time just getting to the board that's under the tubes.
You are so right Roland, but all the units made have the low voltage control board accessible on the right hand side of the units. But you are right, all the power supply stuff is underneath where it is a PITA to get to. I suppose the thought was that the PS will outlast the warranty.