[BC] Checking a modulation choke the easy way

[Michael D. Brown]

Here's a quick way to check the modulation choke on the CCA (or any
other) high-level modulated AM transmitter.
Put a 100 ohm resistor (and a 1or 2 amp fuse on the "hot" side of the AC
line, for safety) in series with the choke and feed 120vac through them.
Measure the voltage across the resistor. At 60hy and 60hz, the choke
will have 22.6k of inductive reactance, so there should be about 1/2
volt across the resistor.  If it's much more, or the fuse blows
immediately, then the choke has shorted turns and must be replaced.
This is a common problem with plate modulated transmitters more than 20
years old. 

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Michael D. Brown (not the FEMA guy)
Brown Broadcast Services, Inc.
    3740 SW Comus St.
Portland OR 97219-7418 USA
     503-245-6065
  mike at brownbroadcast.com