[Amps] Memorial Day weekend amplifier fun/work

[John Lyles]

After a week of troubles with the plate water flow interlock, we changed technologies, and got no more trips. I started a long term heat run Saturday morning, for the TH628 VHF power amplifier that I have reported about recently. 
Now at 56 hours continuous, key down, planning to shut down this week. So far nothing in the cavity amplifier or driver has faulted. The 9 3/16 inch transmission line to the water load is
running between 140-150 deg F on the surface, and load temperature is 139 deg F, with water cooling and a large fan added. Coincidentally, we've had a mini-heat wave this weekend, so the building is about 84 F inside. 
Peak power is still 2 MW, but the average power to the load is 240 kW. Efficiency is 68%, gain 15.3 dB in grounded grid. Still, I cannot get the plate to glow like a 4-1000 would. 
73
John
K5PRO