[AMRadio] Globe Scout now working

w5jo at brightok.net w5jo at brightok.net
Fri Jan 5 10:36:20 EST 2018

Thanks for telling us Charlie,

I have a Globe Champion 300A that had poor audio when I got it.  It, too, 
had a factory mistake in that the bypass capacitor in the second stage audio 
was in backwards, effectively reducing the audio.

Previous owners did not find the problem rather they put 811A tubes in the 
Modulator rather than the stock 809s to increase the modulation percentage. 
After I changed the capacitor, along with all the others that needed 
changing, it worked as it should.  Funny, after all these years finding a 
mistake like that, and congrats on getting the Scout going.

Something that can complicate the WRL transmitters is that the schematic 
shipped with the radio does not always show the way it was wired.  I have 
the original manual for my Globe King 500A and it shows the modulator tubes 
to be 5514 rather than the 811 in it.  The 811 was stenciled on the chassis.


-----Original Message----- 

Thanks to the folks that responded so quickly.  I went back to do a bit more 
troubleshooting and found a 60 year old mistake.  The grid of the pentode 
section of that 6U8 was supposed to have a 220K resistor to ground.  The 
builder of this one, who did a very good job, put a 2.2K in there instead. 
He must have been a CW op only.  Putting in the 220K brought AM to life, 
even with an 8 meg screen resistor.


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This page last updated 22 Feb 2018.