[HBR] Re: GB> RSGB One-Tube Keyer: UPDATE

[Brad Thompson]

At 07:42 AM 5/21/2008, EP Swynar wrote:
>Good Day All,
>
>Well, I've finished construction of the 12AT7 RSGB electronic 
>keyer...and the darn thing refuses to work!
>
><http://www.flickr.com/photos/15888272@N05/?saved=1>http://www.flickr.com/photos/15888272@N05/?saved=1
>
>The oscillator just won't...OSCILLATE for me, that is (that's the 
>first triode section of the 12AT7 in the schematic). I'm going to 
>re-check the wiring yet again, and maybe swap in different 
>components...but at this stage, I'm dead in the water...
>

Hello, Eddy--

Make sure that the transformer's unconnected winding is truly 
unconnected and that its leads are not accidentally short-circuited.
Also, check the connections on the primary side-- if two leads are 
inadvertently swapped, the feedback voltage won't have the proper
phase and the circuit won't oscillate.

73--

Brad AA1IP