To the group: Am reading a max of 400 watts or so on tune up from my Ameritron 800 H when driven with 60 W or so from my exciter. One of the tubes has gone south I hope not? How can/where can they be checked? Everything else is fine other than what appears to be low power from the amp All suggestions are appreciated. And: Merry Christmas to all. 73's, Gary...wa6fgi