View Full Version : ATI EGA Wonder in a IBM PC 5155 with build in composite monitor - no EGA graphics ?

Peter z80.eu
May 23rd, 2017, 07:44 AM
I was able to get an ATI EGA Wonder card for my IBM PC Portable. So I tested what video modes are possible with the build-in composite monitor.
CGA graphics and text modes working fine, as expected. I was also able to switch to enhanced EGA text modes with the help of "SMS.COM", ATI's utility to select several video modes. I was not able to get a good result with an EGA video mode capable game, vertical sync wasn't working correct, picture is scrolling continuosly down, it flickers and there are also additional retrace lines across the whole picture, making it impossible to work with it.
Does EGA graphics mode even interlaced not work with the composite monitor of an IBM PC 5155 ?
The monitor selection is done as recommended in the ATI manual page 13, SW1-8: ON ON ON OFF ON ON OFF ON .
Vertical hold adjustment seems to be a solution, but I am NOT aware of any adjustment possibilities of the build-in monitor...

May 23rd, 2017, 10:30 AM
If by "EGA graphics mode" you mean 640x350, then no, it will not work with the composite monitor. 350-line mode has a scan rate of 21.8 kHz, while a composite monitor only supports the 15.7 kHz scan rate used by the CGA-monitor-compatible 200-line modes.

Peter z80.eu
May 23rd, 2017, 12:33 PM
I guess you didn't read all my words... otherwise you had noticed I mentioned "interlaced" - the ATI EGA Wonder is not a common, simple EGA card, instead, it has some real special video modes. Also, as I already wrote, I was able to get a working picture from EGA text mode using the SMS tool. You can even select Hercules 640x400 mode, and still shows a steady picture, but interlaced. So it would be helpful to get a report from someone who has that card, and not only an opinion about what works and what does not work. Someone here already wrote about it, but it wasn't detailed enough (see http://www.vcfed.org/forum/showthread.php?14364-IBM-Portable-PC-5155 ).

May 23rd, 2017, 03:29 PM
I did read all your words, but you weren't clear about exactly which EGA graphics mode you were in.

I have no experience with the EGA Wonder, but I did have an ATI Small Wonder which could display 720x350 MDA/Hercules graphics on a CGA monitor via interlacing. It worked fine on an RGB monitor but I couldn't get a good image from it in interlaced mode via the composite output. Other people report the same thing, that the composite output doesn't support interlaced mode:


May 23rd, 2017, 08:11 PM
While I haven't set it up myself, I have seen a 5155 with an ATI EGA Wonder working with the built-in monitor. The only EGA modes tested and known working were those that had the same rates as CGA, ie. 320x200 16-color, for which it worked wonderfully. I have not seen any 350-line modes on that monitor, but that doesn't mean it might not work.

I have seen the ATI EGA wonder producing 640x350 on an IBM CGA monitor, and the flicker was so terrible it was generally considered unusable. It's a party trick at best.

May 31st, 2017, 06:29 PM
YES it will indeed work with EGA 640 x350 resolution. I use one in my 5155. Try turning switch 8 off. That disables "Advanced Features" at start up but you can then enable "Advanced Features" with SMS.COM. That' how I have mine set. EGA graphics don't look great on the composite monitor, but they are usable, pretty blurry though due to interlacing. What game are you trying to play. I could try it on mine to see what results I get. There probably is a vertical hold adjustment inside the monitor section but not sure. It could be a bad CAP in there also.

Peter z80.eu
June 5th, 2017, 07:20 AM
Tried a game named "Bicycle Solitaire" which switches to 640x350 pixel (EGA) mode.
Result: http://www.z80.eu/images/Solitair_EGA_640x350_IBM_Portable_PC.JPG

June 5th, 2017, 07:48 AM
OK, I think I found that game. I'll try it later tonight to see if it runs on mine. Did you try turning sw 8 off and then SMS Enab to enable advanced features after boot?

June 5th, 2017, 09:31 PM
Well, it looks like that game behaves the same on mine as it does on yours(sms enab + sms ce80). However, if I connect my external Multisync monitor and run with "Advanced Features" disabled(sms disab + sms ce80), it looks perfect on the external monitor but but the internal monitor is useless in this mode. So, it seems that "bicycle solitaire" does run on true EGA, but it is not going to work with the EGA Wonder interlaced mode on the 5155's internal monitor. There are other EGA games that will work though. MS Flight Simulator 4 is one that works on mine in 640 x 350 mode, but I don't know how many colors it is using, probably only 4. If you want to get the most out of your ATI EGA Wonder, you'll need and external EGA or Multisync monitor.

Peter z80.eu
June 9th, 2017, 02:50 AM
Thank you for testing. Regarding 640x350 resolution, I didn't test Blockout or FS4 so far, but will try this now.

For an updated description what works and what does not, see my blog entry at http://www.z80.eu/blog/index.php?entry=entry170527-150000