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monochrome monitor to rgb connection question [message #80934] Tue, 04 June 2013 00:01 Go to next message
jm is currently offline  jm
Messages: 11
Registered: March 2013
Karma: 0
Junior Member
Message-ID: <51@tekadg.UUCP>
Date: Mon, 5-Nov-84 13:05:51 EST
Article-I.D.: tekadg.51
Posted: Mon Nov  5 13:05:51 1984
Date-Received: Thu, 8-Nov-84 00:19:48 EST
Organization: Tektronix, Beaverton OR
Lines: 37

[]

I tell ya, I got soooo many questions.  Just wish I had some answers...

Problem:  I dislike looking at the text characters on my amdek 300a 
	when connected to my ibm color/graphics card.  But setting the
	6845 crt controller to interlace mode smears the picture.
	I assmue that this is because the amdek has insufficient bandwidth
	to accomodate the interlaced signal (or maybe it's the cable
	playing low-pass filter).

Proposal:  Connect an ibm direct drive monochrome monitor to the RGB output
	of the color card.  Then set the 6845 to interlace mode and see what
	happens.

Question:  Am I gonna blow up the whole mess?  Around here, technical info
	is scarce (odd as that may seem), and ibm doesn't fill in all the
	blanks in my mind with what they do say.  The very minimum I would
	say is that I need to make a new cable.  Then I may have to invert
	one of the outputs (maybe in software?).

I'm afraid my name ain't Mr. Video, so this one goes out to you all.

Next Subject:  What We Need is a library of "Patches, Hints And Kinks" for
	the PC user.  It would save re-inventing the wheel over and over,
	and make hacking (and I use that term advisedly) less fustrating.
	This is the sort of thing that would go in the file.  As would 
	solutions to the "reset memory size after startup" and 
	"reset button" problems...
	Comments?

	Jeff Mizener / Tektronix Portables ADG / Beaverton OR

{ucbvax,decvax,purdue,uw-beaver,hplabs,allegra,ihnp4,ogcvax}!tektronix!tekadg!jm
ARPA:	tekadg!jm.tek@udel-relay 	CSnet:	tekadg!jm@tek

"May your stone always grow rolling grass that is greener underneath."
Re: monochrome monitor to rgb connection question [message #80940 is a reply to message #80934] Tue, 04 June 2013 00:01 Go to previous message
dmt is currently offline  dmt
Messages: 55
Registered: May 2013
Karma: 0
Member
Message-ID: <174@hocsl.UUCP>
Date: Wed, 7-Nov-84 09:26:54 EST
Article-I.D.: hocsl.174
Posted: Wed Nov  7 09:26:54 1984
Date-Received: Fri, 9-Nov-84 06:09:55 EST
References: <51@tekadg.UUCP>
Organization: AT&T Information Systems Labs, Holmdel NJ
Lines: 48

REFERENCES:  <51@tekadg.UUCP>

 >  Subject: monochrome monitor to rgb connection question
 >  
 >  Problem:  I dislike looking at the text characters on my amdek 300a 
 >  	when connected to my ibm color/graphics card.  But setting the
 >  	6845 crt controller to interlace mode smears the picture.
 >  	I assmue that this is because the amdek has insufficient bandwidth
 >  	to accomodate the interlaced signal (or maybe it's the cable
 >  	playing low-pass filter).
 >  
 >  Proposal:  Connect an ibm direct drive monochrome monitor to the RGB output
 >  	of the color card.  Then set the 6845 to interlace mode and see what
 >  	happens.
 >  
 >  Question:  Am I gonna blow up the whole mess?  Around here, technical info
 >  	is scarce (odd as that may seem), and ibm doesn't fill in all the
 >  	blanks in my mind with what they do say.  The very minimum I would
 >  	say is that I need to make a new cable.  Then I may have to invert
 >  	one of the outputs (maybe in software?).

The Monochrome monitor is seriously incompatible with the output of the color
board.
(1)	The signals have different meanings and senses. For instance, the
	mono monitor responds to intensity signals on two leads, while
	the color board RGB output is sorted by color and the composite output
	doesn't have separate sync leads (needed by the mono monitor).
(2)	The mono monitor runs at a higher horizontal sweep frequency
	(by about 20% -- nontrivial). My guess is that would cause it
	to simply not work, though I've heard rumors about this sort
	of thing turning the IBM monitor into a blue smoke generator.
On balance, I'd go with a mono board and the mono monitor (in fact, I did
ten months ago). It generates a DIFFERENT character set, that's much
easier on the eyes.

 >  Next Subject:  What We Need is a library of "Patches, Hints And Kinks" for
 >  	the PC user.  It would save re-inventing the wheel over and over,
 >  	and make hacking (and I use that term advisedly) less fustrating.
 >  	This is the sort of thing that would go in the file.  As would 
 >  	solutions to the "reset memory size after startup" and 
 >  	"reset button" problems...
 >  	Comments?

Except for Norton's book, "Inside the IBM PC", which deals with software
only, I can't think of anything that fits your bill except the 
accumulated annals of net.micro.pc. Continue to subscribe, and ENJOY.

Happy hacking.			Dave Tutelman
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