[Novice-Rigs] EICO 717 Electronic Keyer

[Edward Swynar]

Hi Guys,

This little offering doubtlessly just wouldn't be topical enough for the
Hints & Kinks section of "QST"...! No matter: it just may be of interest to
those owners (are there any even left out there, reading this...?!) of the
vintage EICO 717 tube-type electronic keyer...

Specifically, have you ever noticed that your actual keyed on-the-air
signal---NOT the monitored audio signal from the 717 itself!---evokes
memories of "contact bounce" with just the very first series of dots you
send...? And is your very first dash in a string of dashes noticeably longer
than the ones following it...?

I did with the unit I acquired here last Spring (serial #140-09-9959). I
checked---and re-checked---the voltages & resistances of the tubes, and
found all of the readings to be well within tolerance. I even bypassed the
key output lead, the dot & dash terminals, AND the AC line cord with disc
capacitors & RF chokes, on the assumption that RF was gtting into the
"innards" of the keyer, & affecting it...

The problem persisted, until finally on a whim, I replaced V4---the 12AU7A
dual-triode dot multivibrator---with a 12AX7 dual-triode. Voila! The
gibberish is gone when first sending dots, and the dashes are all the same
length now...

"F.W.I.W."...hey, where else are you gonna dig-up nuggets of information
like this anyway...?!   :>)

~73~ de Eddy VE3CUI - VE3XZ