George Johnson wrote:
> Barry et al,
> Your experience plus the post from KK9A makes me wonder if there is an
> electrical (not S/W) drive problem on those motherboard parallel ports.
> snipped
> I noted in KK9A's post that he used LPT2 (on the SIIG board) successfully;
> not the Dell motherboard port. Hmm...
> A look at the size of the series resistor in the base of the keying
> transistor will allow an estimate of the current drawn from the LPT port.
> George .. W1ZT
------
I believe George has nailed this squarely on the head. Most keying
circuits call for a 1K
resistor in series with the base. For as long as I can remember, I
have used a minimum of
3.3K, and my 2 circuits now ( 1 spare ) both use 4.7K.
May have something to do with computer evolution, but that's just a
guess.
73
Ed
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