IBM 5151 Monitor and EGA Wonder 800+

[TamaMan]

Hi,

Rephrasing my question regarding a setup of an IBM 5170 (8MHz) with an EGA Wonder 800+ card and an IBM 5151 monochrome monitor.

During ATI ETEST "EGA Color Adapter Test", all other graphics modes except "l. 640 x 350 Graphics - 16 Colors" (and most EGA games) will cause the picture to roll.




Is this a known limitation of the 5151 monitor or a matter of adjusting, for example, the horizontal drive slightly? Or something else?

PS. The monitor should be fine, all tests OK with the Graphics Solution Rev 3 card in emulation mode.

Thanks.

-TamaMan

 

[carlos12]

Theoretically and if I'm not mistaken, the only graphic mode that an EGA card can display over an MDA monitor (such as the 5151) is mode 0Fh, 640x350, black and 3 shades of gray (green on this case). So my guess is this demo could be actually using mode 0Fh (maybe it detects the monitor, as it can be done easily by software, but it didn't change the text), or maybe the ATI EGA Wonder 800+ has some kind of routing from mode 0Fh to 10h, or it makes the 640x350 16 color compatible with the 5151 and similar monitors. I don't know the specific details of this card compared with the standard IBM so all this is only a guess.

Anyway, for sure I don't think most games would work, as most of them use mode 0Dh (320x200x16 colors) or, less frequently, mode 0Eh (640x200x16), which are incompatible with the monitor. The frequency is just different. I would stop trying unsupported games as you run the risk of damaging the monitor. Among the few ones that support 640x350 over monochrome monitor I think there is Sim City (I speak from memory, please check it before trying it). Also some version of Flight Simulator may have support for this.

 

[TamaMan]

From https://minuszerodegrees.net/manuals/EGA Wonder 800+ Operation Manual (1st Edition, April 1989).pdf

"Displays EGA, CGA, MDA, Hercules and 132 Columns Software on a TTL Monochrome Monitor.

• Provides wide software compatibility on the TTL monochrome displays, modes which are not normally available.
• Colors of EGA and CGA software are converted into corresponding monochrome gray scale shades.
• No pre-boot drivers are required. The EGAWONDER8OO+ automatically provides these graphics capabilities on TTL monitors"

and later on

"TTL MONOCHROME (18.43KHz)

These monitors are designed to be used with Hercules or MDA cards. With the EGAWONDER8OO+, the following software standards can be displayed:

• Monochrome text mode
• Hercules text and graphics modes 720x348
• RGB text and graphics mode 320x200 - in 4 or 16 shades
• EGA text and graphics mode - 640x350 in 2 or 16 shades
• 132 columns x 44 rows text for software which either supports this mode or by drivers which are provided by ATI Technologies Inc. on the disks supplied with the card."

OK, now as I am pasting the above, I realize that "EGA graphics" is only mentioned on that one working mode. Perhaps there was less market for supporting wider range of EGA modes on TTL monochrome monitors in late 80s. If it would have been even technically feasible as the CGA emulation mode in other earlier ATI cards.

-TamaMan

 

[Plasma]

According to the manual, other modes should work. The EGA Wonder is not a regular EGA card and doesn't have the limitations of the IBM EGA. Possibly one of the crystals on your card is bad.

 

[TamaMan]

Just found in the driver setup README file mention of grey scale optimization blinking in certain "animated" EGA games when using a monochrome TTL monitor. Games mentioned are Gunship, F19 Stealth and World Tour of Golf. So this hints that EGA games should work.

I think I'll start off by adjusting the drives on the 5151 if they are just slightly off for the EGA Wonder 800+ card. IBM MDA and ATI Graphics Solution Rev 3 work fine in all modes.

 

[TamaMan]

Before opening the 5151, I tried F19, Gunship and World Tour of Golf with the README mentioned grey scale optimization disabled and enabled ("ECONFIG MASK BA FF 40" and "ECONFIG MASK BA BF 0"). No change in the rolling of the picture.



The card seems to have three clock generators. As games work OK with CGA selected, I wonder which are related to the emulated EGA modes? Also as I don't own a scope, only an UT61D multimeter, I'll need to investigate how verify the crystals.

 

[modem7]

The card seems to have three clock generators. As games work OK with CGA selected, I wonder which are related to the emulated EGA modes? Also as I don't own a scope, only an UT61D multimeter, I'll need to investigate how verify the crystals.

A borrowed oscilloscope would also allow you to see (out of curiosity) what is going on regarding the vertical sync pulses out of the card. E.g. During 'rolling', is it that the vertical sync pulses are missing? Or, no longer 50 Hz? Or, changed from negative to positive going?

 

[TamaMan]

Yes, with a scope and the mentioned MDA/CGA/EGA signalling information the root cause could be possibly solved. Thanks for the link.

Just as additional information, here's ESETUP:


and ECONFIG:


PS. If someone with a 800+ hooked up to a 5151 could verify that all other EGA graphic modes/EGA games should work OK. Thanks!

-TamaMan

 

[TamaMan]

Update on the Horizontal and Vertical Retrace pins on the 800+ card. Using a multimeter in the "Hz" mode, I got the below results. I made a small INT 10h ASM program to switch between modes using 0-9 keys from the keyboard as I disconnected the 5151 just prior to taking the measurements.

CGA selected in ATI's ESETUP.
Modes 00h to 07h (picture OK):
Pin 8 (H.Sync): 17.45 kHz
Pin 9 (V.Sync): 47.54 Hz

EGA (C80) selected in ATI's ESETUP (then power off and on cycle as suggested by ESETUP).
Modes 00h to 06h (picture rolling)
Pin 8 (H.Sync): 17.56 kHz
Pin 9 (V.Sync): 41.96 Hz (peaks at 45.67 when changing modes)
Mode 07h (picture OK)
Pin 8 (H.Sync): 18.32 kHz
Pin 9 (V.Sync): 49.53 Hz

If I understand these results correctly, pin 9 (V.Sync) is perhaps just too much out of tolerance for my 5151 when the card is configured for EGA and modes 00h-06h are used?