Guys,
I need some serious help here.
I'm trying to get NA to key my rig. It's beginning to look like
there is a problem with the Computer/Interface. That is, the standard
parallel port interface won't work.
NA is doing everything it should, I think. I checked the voltage on
pins 17 and 18 of the db-25 parallel port and it changes from about .06V
to 2.5V or more when the computer sends code. The voltage varies with
the code sent. (in other words, I can see the dots and dashes.)
Scope shows the same voltage change, however, I also saw some RF along
with the DC voltage. A .001 capacitor between pins 17 and 18 seemed to
eliminate the RF, but The rig is still not keyed.
I've checked the cable. Actually, I made a little db-25 with the
interface circuit on it in the open so I could check voltages, etc.
I need some electronics help here. Anybody know what the parallel port
is supposed to do, and how to convert it's action to a switch that will
key the rig?
I connected my hand key to the rig and verified that it keyed OK. Then,
I connected the above circuit in parallel with the hand key. This
circuit operated as above, but would not key the rig.
Can someone help with this problem? I suspect that my computer is
working in a different manner than earlier models, and it may require
some changes in interface design. Of course, I could be nuts, and need
to put my tongue on the other side of my mouth when I key... Whatever
the solution, it escapes me.
Help!
--
73,
Bob Kellogg, AE4IC
Prolably, not nececelery. -Benny Hill
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