At least one of the 3CX800s in my AL-800H apparently had been "flashing
over" every now and then as evidenced by blowing the diode protecting the
metering in the amp. I followed the recommendation received in this forum
regarding judicious application of hammer blows to the tube to dislodge
possible gold particles and eliminate the problem (nothing to lose!).
Holding the tube in one hand with a 1" board resting on the plate cap, I
applied about a dozen firm blows with a small hammer to the board. I
reinstalled the tubes, making sure to keep them upright all the while, and
apparently the process cured the problem, at least for now. They've been
idling with full plate voltage on them for a couple of days, with an
occasional QSO, and no flash-overs yet. Full power out on all bands with no
unusual behavior observed.
K8AC
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