Hal, The beauty of the header strips is that the Z3801A can easily and quickly be converted back to RS-422 in the future, without having to partially dismantle the unit and do more soldering- again.
73, Eric Lemmon WB6FLY -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Friday, March 30, 2012 11:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP Z3801A Sale > There really is nothing much to this "modification." The Z3801A is already > designed to easily work on either interface, but most units are configured > for RS-422 as the default. It takes perhaps a half-hour to remove some > zero-ohm SMD resistors and solder in a few header strips. The simple procedure > is described and illustrated here: <www.ad6a.com/Z3801A.html> You don't need the header strip. There are empty slots waiting for some of the 0-ohm jumpers you have to remove. I think they are the three to the right of the circle in figure-13 of the above URL. You can work out which is which by following the traces or using an ohm-meter. Here is another URL in case you want a second opinion: http://support.ntp.org/bin/view/Support/Z3801AReceiverModifications -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.