What monitor are you using ? Why I ask is that diff LCD monitors have diff built in capability. example: Samsung 914v and 930B directly supports 640x350 where the Dell 1908fp does not and would probably try to scale to 720x400 which would leave bars..
Am sure someone more knowledgeable will have better info but am sure that could be the issue....

Monitor is an EIZOS Flexscan 1701

According to the SpecSheet (attached) it probably cant do 640x350. Would that be the issue ?

thanks

Ok - I tried two additional screens and it seems the combination of:

EGA card + EternalCRT + LCD screen can lead to rather arbitary results:

EIZO screen: NC=720x400 (poor text)/ PRINCE=640x480 (horizontal and vertical black bars )
SAMTRO S51 (15inch LCD) NC=640x350 (good text but bars at top and bottom - compressed ?) / PRINCE 640x480 (horizontal and vertical black bars compressed ?)
DELL (E190S-5:4 19inch LCD) NC640x350 ((good text but bars at top and bottom)) / Prince 720x480 ((horizontal and vertical black bars )

Im not sure how a "correct image" should look like. It seems that the DELL screen (being 5:4 aspect ratio) accidentaly looks more or less ok (just subjective impression)
Forcing 640x480 in the EIZO and SAMTRON makes the image look vertically compressed it seems. The non native 720x400 at the EIZE screen makes text look horrible. Still not sure how to get this right.

Aui wrote on 2024-10-31, 07:34:

Im not sure how a "correct image" should look like. It seems that the DELL screen (being 5:4 aspect ratio) accidentaly looks more or less ok (just subjective impression)

You are never going to get a perfect image on an LCD, you'd need something capable of 4k resolution but in 4:3 or at least 5:4 aspect ratio to have the pixels required for correct scaling. Frankly black bars might be preferable to the monitor forcing full screen and some weird scaling ration that will result in blurry image or some edges being thinner or thicker. Example: 1280x1024 19" LCD can do perfect scaling of 640 in horizontal direction but 350 vertical is another story. The best looking would probably be 2.5x350=875 with the rest being black bars, end even that will have some issues due to being .5 and not an integer number. But 2x would result with 700 lines, which is better for pixel scaling but might result with excessive black bars and wrong aspect ratio - keep in mind the original EGA had quite some gaps ("scanlines") between each horiztonal line to fill the entire screen. You'd need about 4x the resolution on monitors with fixed pixels to represent that properly. Perhaps 3x would be good enough, a bit fuzzy in some lines but the black ones would appear to inrease the sharpness.

TL;DR: You want EGA to look good, you need EGA CRT monitor. Or at least a decent SVGA CRT and some good upscaler. LCD can be better or worse, but never perfect. And black bars are often preferable to broken full-screen scaling.

Thanks - Im currently on a really steep learning curve (scanlines, frequencies, aspect ratios, square and not so square pixel - which actually are not pixel at all but scanlines). EGA monitor is probably out of the question unless I make a really lucky find. Equally regretable is that I have discarded my last VGA CRT a while ago. Maybe I find at least one of these. For now I will have to accept the less than perfect LCD solution.

Just realized how prophetic Will Wright was when crafting his Sim City scenarios...
(taking full advantage of my advanced EGA system )

Aui wrote on 2024-10-31, 07:34:

Im not sure how a "correct image" should look like. It seems that the DELL screen (being 5:4 aspect ratio) accidentaly looks mor […]
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1EIZO screen:                                          NC=720x400 (poor text)/ PRINCE=640x480 (horizontal and vertical black bars )
2SAMTRO S51 (15inch LCD)             NC=640x350 (good text but bars at top and bottom - compressed ?) / PRINCE 640x480 (horizontal and vertical black bars compressed ?)
3DELL (E190S-5:4 19inch LCD)     NC640x350 ((good text but bars at top and bottom)) / Prince 720x480 ((horizontal and vertical black bars )

Im not sure how a "correct image" should look like. It seems that the DELL screen (being 5:4 aspect ratio) accidentaly looks more or less ok (just subjective impression)

(I added "code" markup to the quote to not mess up the table-like layout)

It seems the EternalCRT provides modes at the output that are unexpected by the digital logic of your LCD screens. This product is based on the MCE2VGA logic, which has some more in-depth description of the modes here: https://www.serdashop.com/MCE2VGA . As PRINCE is running in EGA low-res, the converter is intended to output 720x480 pixels (which has standard VGA frequencies, but the combination of 720 horizontal and 480 vertical resolution is not used by any mode supported by the VGA BIOS), with black bars all around the image. This is likely designed that way to be able to display the CGA overscan ("border") area around the image. The actual image is 640x400 pixels, created from doubling the 320x200 mode used by PRINCE. This means we expect a 40 pixel black border (which can be turned non-black if the software desires, e.g. Commander Keen 4 will turn it cyan) around the whole image.

In EGA high-res mode, the output is 640x350, which is a standard VGA mode. The NC text mode is "EGA high-res".

It seems the DELL monitor perfectly picks up the signal properties from the EternalCRT converter. As the EternalCRT is not supposed to add black bars at the top and bottom in that mode, this is likely how the SAMTRON and DELL monitor handle the 640x350 mode. You can get any VGA card to generate the same mode by using high-res EGA software, and test how these monitors react to 640x350. For example you can use checkit: It will display a grid image in "mode 10h" during the video tests.

Aui wrote on 2024-10-31, 07:34:

The non native 720x400 at the EIZE screen makes text look horrible. Still not sure how to get this right.

On BIOS-programmed modes, VGA output is 640x350 in EGA-like modes (text mode in their compatiblity variant and high-res EGA graphics mode), 720x400 in VGA text modes, 640x400 in CGA and EGA low-res modes as well as the 256-color mode (320x200 or 640x200, those modes are double-scanned) and 640x480 in high-res VGA graphics. The VGA card is supposed to signal the line count to the monitor using the polarity of the sync signals. The EternalCRT is supposed to signal "350 lines" to the LCD monitors when in EGA text (or hi-res graphics) mode, so I have no idea why the EIZO monitor picks up 400 lines. 400 lines is indeed difficult for the monitor, because there are both 720x400 and 640x400 modes, and chosing the wrong one leads to bad results (as you see). Possibly, the monitor tries to detect whether the mode is double-scanned or not (double-scanning indicating 320x200 or 640x200, whereas 400 individual lines indicates 720x400). As the EGA test mode is not double-scanned, this would explain the wrong choice of 720 instead of 640 horizontal pixels.

In summary: It seems the DELL monitor is the only one that picks up all modes correctly. The four-way black frame around PRINCE is supposed to be a "feature", not a "bug". The black top/bottom borders on the SAMTRON monitor is caused by that monitor to scale the 640x350 image to 1024x700 (doubling the line count), so 68 lines are missing. Using just 700 lines allow easy, yet good-looking interpolation which produces an image that will be percieved "better" by most viewers than trying to re-scale to 768 lines, even if it causes a slight amount of compression. On the other hand, I don't see how the borders on the DELL make sense from that perspective, as the target line count of 1024 lines is still below 350*3, but the image is obviously higher than 350*2. I guess those bars are meant to get the image into the 4:3 ratio. Nothing in your image indicates that any enhanced capabilities / modes of the JEGA card are used, and I'm afraid that the EternalCRT is most likely not handling them at all.

Hi could you dump the jega card video rom? also which computer are from?

Aui wrote on 2024-10-29, 01:38:

Hi everyone, my first foray into EGA territory (I already think maybe I started off too difficult) […]
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Hi everyone, my first foray into EGA territory (I already think maybe I started off too difficult)

I have been trying to set up a Japanese AX - JEGA card with only partial success. From what I understand, the card should be capable of both a normal EGA mode and an "enhanced" EGA mode to display (more delicate) Japanes characters. When Im operating the card in DOS (Using Monotech-EternalCRT on an LCD screen !), I seem to get correct EGA color palette but the image has large black bars at the top and bottom. In addition - text resolution seems to be somehow off, with poorly displayed, smeared out characters. According to the Wiki - JEGA has a resolution of 640 × 480 (this is not VGA) rather than the 640 × 350 standard EGA resolution.

My questions are this: Would an normal EGA card always leave top and bottom bars on an LCD screen (640x350 is not 4:3 after all) or Is the reason for these bars the JEGA mode. If so - any ideas how to acess it or change it. I tried the dip switches on the card but they dont seem to be the solution. It rather seems I need to get acess to the cards BIOS somehow? Any help or suggestions wold be appreciated.

(I also tried to find and translate something about Japanese maker of the card 'ProSide' company, but there is not much I have found / no drivers manuals etc seem to be available)

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And do you still have the card?

Yes I have the card. I also plan to get the ROM at some point. I dont have a BIOS / ROM reader / writer and no experience. I am planning to learn (and get the required equipment) but currently I dont have enough time for such a deep dive.

The card came from this Computer:
ProSide 386DX 25 -Battery Damage

It is some no name (Proside?) AT clone. I had to replace the mainboard because despite replacing a large number of traces, it would not come back to life. The new board has identical specs and runs perfectly fine. The machine is now my goto "pre-Win 3.1." EGA machine.