[BC] The last of the tube 1000 watt transmitters

[gRAdy Moates]

I had a 20V3 in Starkville, MS at WKOR, and a 20V2 at WJHO in Opelika, AL.

I cut my teeth on that 20V2. . . I was a 19-year-old DJ there, when 
it stopped working on a Sunday morning, and the manager and part 
owner (Smilin' Jack Smollon) woke me up and brought me in to help him fix it.

That was the day I learned to trust the test equipment!
The bias supply was reading about -12 Volts, when it shoulda been 
-120 Volts.  When I saw that reading, I said, "must be the Simpson 
meter" and moved on.
An hour later, when I still hadn't found anything wrong, I said, 
"What if that was a correct reading?" and found that the DC blocking 
cap on the modulation monitor output sample from the 20V2 was 
shorted, leaking the bias voltage to ground through the "arc-quench" circuit.

Some lessons you never forget!

Grady
>The last Collins 20V3s were manufactured in 1968 + or - 2 at their 
>Dallas plant.  They were 100% tubes (including an 807 driver) to the 
>very end.  I think they even used mercury vapor rectifiers, 
>also.  The replacement was the 820-D which used 5-500 tubes.
>ron