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- Xref: sparky comp.sys.ibm.pc.hardware:21702 comp.windows.x:15173 comp.unix.sysv386:13077
- Newsgroups: comp.sys.ibm.pc.hardware,comp.windows.x,comp.unix.sysv386
- Path: sparky!uunet!pipex!ibmpcug!exnet!exnet2!jshark!lowton!mark
- From: mark@lowton.rn.com (Mark Powell)
- Subject: Orchid Prodesigner IIHCs and Sampo Alphascan 15
- Message-ID: <1992Aug12.132821.742@lowton.rn.com>
- Sender: mark@lowton.rn.com (Mark Powell)
- Organization: Mark-one Communications
- Date: Wed, 12 Aug 1992 13:28:21 GMT
- Lines: 53
-
- An X386 question:
- I have an Orchid Prodesigner IIHCs and a Sampo Alphascan 15
- monitor. I got the Xconfig database off of comp.windows.x
- some weeks ago and from it I see my card can clock up to 75MHz.
- (I'd previously only been using the 65MHz clock which I was told existed.)
- The Sampo can sync. up to 60KHz according to docs. (anyone
- know better?), but when I try the following Xconfig values
- I get a steadier picture (higher vertical sync.) than a 65MHz clock,
- but there is image breakup on vertical lines.
-
- ###############################################################################
- # Card: Orchid ProDesigner IIs
- # Contributor: David Wexelblat [dwex@mtgzz.att.com]
- # Last Edit Date: 10/14/91
- #
- # chip ram virtual clocks default-mode flags
- ET4000 1024 1152 900 25 28 32 36 40 45 75 65 "1152x864"
-
- # name clock horzontal timing vertical timing flags
- "640x480" 25 640 672 768 800 480 490 492 525
- "800x600" 36 800 848 920 1056 600 608 610 633
- "936x702" 65 936 968 1168 1208 702 747 788 810
- "1024x768i" 45 1024 1064 1224 1264 768 777 785 817 Interlace
- "1024x768" 65 1024 1064 1128 1280 768 768 770 800
- "1152x864" 75 1152 1200 1248 1400 864 864 876 900
-
- Monitor's fastest horizontal sync.= 1/60000 = 16.67us
- 1152x864 mode horizontal time = 1/75000000 * 1400 = 18.67us
- 18.67us = 1/18.67e-6 = 53571Hz (well below the 60KHz maximum monitor sync.)
-
- This is the original database entry with the numbers trimmed a little
- in the "1024x768" line and my own "1152X864" line. The "1024x768" is
- fine at 65MHz, but if the clock value is changed to 75 in Xconfig and
- X restarted the display is steady, but again with vertical line break-up.
- The monitor cable is supposed to be shielded and the monitor doesn't seem
- to be near any RFI source.
-
- Anyone any ideas why this is happening?
- I can only assume that the Sampo is not up to it's specs.?
-
- Thanks in advance.
-
- BTW Even though using 75 gives break-up maybe I'll keep using it if it's
- better for my eyes. Anyone agree? Maybe a repost to sci.med? I'm
- using 75 at the mo. to post this article, so the break-up isn't bad,
- just annoying after sitting down and working out that from the specs.
- this card and monitor should provide a 1024x768 at around 70Hz. Only
- to find I've got to settle around 60Hz.
- --
- Mark Powell
-
- mark@lowton.rn.com Home: +44 942 714317
- uunet!gator!jshark!lowton!mark Nr. Manchester, UK.
-