[R-390] Bad solder joints in other projects (long)

Tue, 2 Apr 2002 08:35:18 -0600

Bruce,

I originally had an external supply for this keyer as well and I think it was helping to introduce RF into the mix.  When I rebuilt it, I used an internal-only supply of three AA cells.  The only connections I have now are the paddle and output.

I also have an attic antenna at about the same distance.  I think that's probably my biggest problem.  Oh for an outside antenna... sigh...

73,

Barry - N4BUQ

Barry,
I had a similar RF induced problem with my "store-bought" keyer- an MFJ 
model which has the electronics in a metal box mounted to a Bencher paddle. 
No problem when using the internal 9V battery, but it would "lock up" on 
some bands when using the wall wart for power, which apparently makes a nice 
receiving antenna. This was fixed by wrapping the wall wart cable about 5 
turns through a randomly selected ferrite core- a little donut about an inch 
in diameter- just where it plugs into the keyer. An aggravating factor is 
probably that my antenna, a 52 ft. long G5RV dipole, is in the attic, only 
about 20 ft. away.

Moving back to R390 stuff- I followed Jim Temple's saga and hopefully 
learned a few more troubleshooting tips. Thanks to all who helped. I feel 
inspired now to get the bench cleared off (yikes-it's scary) and resume 
debugging the R390.

73, Bruce
WA4ZLK

>From: "Scott, Barry (Clyde B)" <[email protected]>
>To: "R390 (E-mail)" <[email protected]>
>Subject: [R-390] Bad solder joints in other projects (long)
>Date: Mon, 1 Apr 2002 13:53:25 -0600
>
>Warning: Do not proceed if sand hurts your eyes...
>
>I had an interesting experience this past weekend.  I built a Super CMOS 
>III keyer a few years ago.  I originally housed it in a plastic enclosure 
>and was having problems with it going bananas when I tried to use it with 
>the transmitter at full output.  Apparently it was a problem with some 
>small amount of stray RF getting to the keyer's components.  The designers 
>suggested I move it to a metal enclosure which I did.  It solved the 
>problem of the keyer losing its mind, but I created another problem.