> If you will recall, in the mid-1980's, there was a massive recall of all
> 8877's by Eimac.
Apologies if I've repeated this story in the past...
There was a wave of contaminated Eimac 8877s that preceded the 1985 event.
It nearly cost me my college job when I was working at a small FM station in
Rockford, Illinois between 1978 and 1979. Long story short: An AEL FM-2.5K
transmitter used the 8877 to produce approximately 2250 watts into a
three-bay circularly-polarized antenna.
One day, an air blockage caused the 8877 to overheat -- to the point where
the anode turned pitch-black. At the same time, grid current was running
dangerously high in order to produce the full licensed TPO. I drove to
Richardson Electronics in the Chicago suburbs and purchased a replacement
8877. Upon installing it, no amount of drive, nor tuning would bring it
near full power and cavity tuning adjustments were way outside of normal.
Purchased a second tube. It behaved exactly the same as the first.
Purchase a third tube. It too behaved the same...
Thinking that the problem was me and not the 8877, the station's owner flew
in a consulting engineer and paid him several $K to tell him what I already
knew, but being only 20 years of age, I was beginning to question my
analytical troubleshooting skills. There's nothing like the pressure of
being off the air with zero ad sales to test one's ability to work under
extreme pressure. And extreme it was.
Somehow, I ended up speaking with Eimac's Reid Brandon who informed me of
the bad batch of 8877s. He sent me one directly from Eimac's Salt Lake
City facility. I installed it in the AEL transmitter and it performed 100%.
I was tempted to tell the owner "told 'ya so," but reserved that remark for
another occasion.
Needless to say, grades suffered that week but it was quite an experience
I'll never forget. I still use an 8877 in my Alpha 77Dx. I'm reminded of
the Rockford event every time I put my hands on an 8877.
Paul, W9AC
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