[HBR] Fw: RSGB One-Tube Keyer: UPDATE

[William Hopkins]

Hello everyone, 

I built the 1960 ARRL Handbook keyer back about 10 years ago. I don't remember anything difficult about getting it to oscillate. (Translation: I was lucky.) Have you put it on a scope? Also, have you checked to see if it indeed is oscillating - all the time - but seems to be doing nothing? Again, do you have any kind of voltage across the output to the relay (I guess that's what you are using; I used a mercury switch.) Third, the high value resistors in the circuit for weight, etc., make for little leeway in adjusting the differences between the dots and dashes, but I'm confident an alternate way can be found around that. Last, as I remember, there is a large value cap in the circuit for delay (you can see I'm not at the home QTH as I write this). Is that cap the right value and is it functional? Did you try another tube? What does the power supply output ripple look like? 

Good luck. 

73's 
Bill Hopkins, AA2YV 


----- Original Message ----- 
From: "EP Swynar" <gswynar at durham.net> 
To: hbr at mailman.qth.net 
Sent: Wednesday, May 21, 2008 7:43:51 AM (GMT-0500) America/New_York 
Subject: [HBR] Fw: RSGB One-Tube Keyer: UPDATE 

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 

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... 

Too bad, because it was really beginning to look like something...! 

Does anyone with any past experience with such devices maybe have any words 
of wisdom they might share with me in my quest for a cure...? There was a 
"one-and-a-half" tube version of this very keyer featured for years in the 
early 60's editions of the ARRL's HANDBOOK --- maybe some of you guys who 
built it back then have some tips. 

Many thanks in advance...! 

~73~ Eddy VE3CUI - VE3XZ 

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