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From: myers@hpfcdj.HP.COM (Bob Myers)
Newsgroups: sci.electronics
Subject: Re: VGA monitors
Message-ID: <17660167@hpfcdj.HP.COM>
Date: 21 May 91 17:58:25 GMT
References: <1991May18.074619.18581@kcbbs.gen.nz>
Organization: Hewlett Packard -- Fort Collins, CO
Lines: 21


I don't think that this is an issue of whether or not the card "knows" that
there is a monitor out there, but rather whether or not the signals are
properly terminated.  Without the monitor, the gear you're using may not
terminate the video and/or sync signals in the expected impedance (75 ohms
for the video; your guess is as good as mine if you have separate sync - I
don't recall the VGA system very well at the moment).  Check near the input
connectors of the video projector, interface, or whatever else you're using
for switches which may be marked "Hi-Z/75 ohms" or something like that.  If
you're NOT going to use it in parallel with a monitor, then set these to the
"75 ohms" position.

Another possibility is that your gear is expecting sync from the wrong place
(there'd be a switch for this as well).  This is less likely, as you say that
it works just fine when the monitor is connected in (and I assume everything
else remains the same).


Bob Myers  KC0EW   HP Graphics Tech. Div.|  Opinions expressed here are not
                   Ft. Collins, Colorado |  those of my employer or any other
myers@fc.hp.com                          |  sentient life-form on this planet.