rh2y+@andrew.cmu.edu (Russell E. Hoffman, II) (05/30/90)
I have a PBJ Word-Pak II for my Color Computer that I've had for about a year. In the documentation for the OS9 driver for the WordPak, there is mention of making some changes to bytes at certain offsets in the driver module to change the setup of the video registers. This is supposed to help accommodate different types of monitors. I have a Gorilla "high-resolution amber" monitor. It is a composite amber monitor for 80x25 text. Does anybody know the correct offsets to change for this particular monitor. The problem is that while the display looks fine, it slowly oscillates up and down a little bit, which gets annoying after a while. Thanks in advance. Russell Hoffman Carnegie Mellon University rh2y+@andrew.cmu.edu rh2y@unix2.andrew.cmu.edu
knudsen@cbnewsd.att.com (michael.j.knudsen) (06/02/90)
>[Monitor picture moves up and down slowly]
Russ, soundslike your Gorilla has a weak filter capacitor in its
power supply, so some 60-cycle hum is leaking into its circuits.
This is beating (heterodyning) with Coco's 60-Hz vertical frame
rate, and causing the slight drift in vertical position.
Only fix is to replace the big electrolytic cap, or better yet add
another one in parallel with it. I doubt very much this is the
WordPack's fault. (I have one I'd love to sell cheap).
Sounds like there are lots of Coconuts at CMU, my PhD alma mater.
Do you know Walt Wimer?
--mike k
--
"Round and round the while() loop goes;
Whether it stops," Turing says, "no one knows."kirkenda@eecs.cs.pdx.edu (Steve Kirkendall) (06/03/90)
In article <1990Jun1.221140.11668@cbnewsd.att.com> knudsen@cbnewsd.att.com (michael.j.knudsen) writes: >>[Monitor picture moves up and down slowly] > >Russ, soundslike your Gorilla has a weak filter capacitor in its >power supply, so some 60-cycle hum is leaking into its circuits. >This is beating (heterodyning) with Coco's 60-Hz vertical frame >rate, and causing the slight drift in vertical position. > >Only fix is to replace the big electrolytic cap, or better yet add >another one in parallel with it. I doubt very much this is the >WordPack's fault. (I have one I'd love to sell cheap). There is another possibility: magnetic interference. On my Atari ST system, I have to keep my printer at least 9 inches away from my monitor, or my picture jitters like mad. I remember some other guy who had trouble because the the main power feed for his entire house went through the wall behind his computer. Try relocating some or all of your system's components. If stray magnetic fields are causing your seasick display, then this should solve it. ------------------------------------------------------------------------------- Steve Kirkendall kirkenda@cs.pdx.edu uunet!tektronix!psueea!eecs!kirkenda
rh2y+@andrew.cmu.edu (Russell E. Hoffman, II) (06/03/90)
>[bad filter capacitors....]
Nope Survey says XXX. There isn't anything wrong with the filter caps in the
supply, because when I run the PBJ driver in Greg-E-Term (a p.d. terminal
emulator), the display looks fine, which I am assuming means that the Greg-E-
Term driver uses different register values. Also, when I go from using Greg-
E-Term to using the OS9 driver, I have to re-adjust the vertical hold on the
monitor, further making me conclude that there are different register setups
being used.
Possibly does anybody know of a way that I can determine what register values
are used by GETerm and apply them to the OS9 driver? I'm not sure where they
can be found.