Do you have a real Hercules card, or some clone?
It looks like the game reprograms the active scanline width, and your hardware does not handle that properly.
That could either be caused by a bug in the hardware or a bug in the game.
I own a real Hercules card, so I might be able to give the game a look on my machine, assuming it runs on a 8088.

I have an Hercules clone card. All other games works...

If i select Hercules option:
As you say is probably doing some low-level work on the hercules that depends on a real hercules card, i'm doomed.. 😜
I tried on a real 286 12mhz with the hercules clone card, i never see an hercules real card on my country. Even Hercules clones cards are difficult to get today...

If i select CGA (previously SIMCGA loaded) option:
It displays perfectly, but before start the gameplay it hangs on the screen with character sleeping on the tree. I assume that runs some hardware routine that is not catched by SIMCGA

MMmmmm... if you try on your machine and it works, at least I can clear up the doubt

And the plot thickens. It works perfectly well on a Schneider Euro PC (obviously clone, not Hercules). Configured for Hercules, nothing else like simcga loaded.

It works on my Hercules GB102 card as well.
I'd have to check what the code does exactly, it probably sets up some kind of tweaked mode, and your clone may not be compatible. Other clones may be 😀

I got the following CRTC register values for the videomode it uses:
0x0: 53
0x1: 40
0x2: 44
0x3: 7
0x4: 123
0x5: 2
0x6: 100
0x7: 108
0x8: 2
0x9: 2
0xA: 0
0xB: 0

In register 0x1 we see that it sets an active scanline width of 40*16 = 640 pixels.
Register 0x9 tells us that it uses (2+1=) 3-scanline interleave (standard 720x348 uses 4-scanline interleave).
Combine that with register 0x6 and you get 100*3 = 300 total scanlines.
So it sets up some special 640*300 mode.
It seems to set up the vertical adjust register incorrectly though. It sets (123+1)*3 scanlines as vertical total, which gives us 372 scanlines. Then it adjusts by 2 scanlines, for a total height of 374 scanlines. That is slightly more than the 370 scanlines that regular Hercules/MDA modes use. I think they should have programmed it to vertical total of 122, and then a vertical adjust of 1, so you'd get 123*3 + 1 = 370 total scanlines per frame, at a slightly higher framerate than what you have now.

It also seems to set textmode about a dozen times before it switches to graphics mode (which it only does once, heh).

😖.. now this became personal.. me against prehistorik.. 😜

Thanks for the responses and took the time to test on your computers

Love the tech stuff Scali. That confirms that it uses rare resolution.

I will try other Hercules clone cards that I have at my disposal, because the rare resolution, can be the monitor too?

fede2222 wrote:

I will try other Hercules clone cards that I have at my disposal, because the rare resolution, can be the monitor too?

I don't think so.
It programs a total screen of 864x374, which is very close to the standard 864x370 in Hercules 720x348 graphics mode.
Most monitors should have plenty of tolerance to handle those extra 4 scanlines. And if they don't, you'd see the screen rolling vertically, and I don't think that's what happens. You only have horizontal distortion of the image, correct?

Well... after the little demons fall asleep, i can do the tests...

First i tried changing the monitor, then tried changing the hercules card. The problem was SOLVED.. but, a new mistery arrived...

With this Hercules clone card, the one that was in the machine and has the flickering

Hercules Samsung Ambar Phosphorus Monitor

Hercules (other brand) White Phosphorus Monitor

Hercules TRL White Phosphorus Monitor


At this point my first impression was the monitor is the problem...

but...

With other Hercules clone card that i storage for spare parts

Hercules Samsung Ambar Phosphorus Monitor

Hercules (other brand) White Phosphorus Monitor


At this point i have second thoughs... why now is working on the Samsung Monitor??

Conclusion... ¿?
I will use the other hercules card, because i love the ambar hercules screen. But the hercules card that made the flickering on the ambar monitor works perfectly on the white monitor...

I don't know why.. 😠

Now i can play prehistorik.. but the mistery remains... 😕

That's interesting.
My guess is that the problem is with the card, not the monitor.
Since other cards work fine on that monitor with the same game.
I think the card generates a wrong signal for that specific mode. Somehow some monitors can handle it anyway, others can not.

One thing I noticed is this:
The Winbond card uses a 16.257 MHz crystal. This is not the correct speed for Hercules, but it is correct for MDA.
The SiS card uses a 32.000 MHz crystal. I assume it divides the clock by 2 to get 16.000 MHz. This is the correct speed on Hercules.

The difference should be within the margin of error, but perhaps that one monitor is very sensitive. Even so, I'd expect it to have problems with more games then.
Does the monitor have any kind of horizontal controls? Like h-width or h-hold or such? If it does, perhaps you can tweak them a bit, and it may make the image stable.

what is the extra chip that you could plug into that empty chip socket on that Winbond card?

Scali wrote:

That's interesting. My guess is that the problem is with the card, not the monitor. Since other cards work fine on that monitor […]
Show full quote

That's interesting.
My guess is that the problem is with the card, not the monitor.
Since other cards work fine on that monitor with the same game.
I think the card generates a wrong signal for that specific mode. Somehow some monitors can handle it anyway, others can not.

One thing I noticed is this:
The Winbond card uses a 16.257 MHz crystal. This is not the correct speed for Hercules, but it is correct for MDA.
The SiS card uses a 32.000 MHz crystal. I assume it divides the clock by 2 to get 16.000 MHz. This is the correct speed on Hercules.

The difference should be within the margin of error, but perhaps that one monitor is very sensitive. Even so, I'd expect it to have problems with more games then.
Does the monitor have any kind of horizontal controls? Like h-width or h-hold or such? If it does, perhaps you can tweak them a bit, and it may make the image stable.

It makes sense... The game that i detected the problem so far is prehistorik, but i don't know what other games use "particular" ways to use the display.. In the recent 2 weeks i install 40 games, no problem at all. Will see...

The monitor has potentiometers to adjust h-width and v-height, i assume the third may be h-sync/refresh/frequency.. who know?.. but is blocked..

i take the photo previously to get to work... i will try tune up tonight with the Winbond.

Joey_sw wrote:

what is the extra chip that you could plug into that empty chip socket on that Winbond card?

😕 😕 ... don't know... never took attention to that socket before...

The clone card has an LPT port plus the video port... but the LPT port is functional... so, don't know what the use of this socket..

fede2222 wrote:

It makes sense... The game that i detected the problem so far is prehistorik, but i don't know what other games use "particular" ways to use the display.. In the recent 2 weeks i install 40 games, no problem at all. Will see...

Have you tried the game Hexsider? It supports two Hercules modes, one of them uses a similar tweakmode to Prehistorik. The other is a slower 'compatibility' mode.

Scali wrote:

fede2222 wrote:

It makes sense... The game that i detected the problem so far is prehistorik, but i don't know what other games use "particular" ways to use the display.. In the recent 2 weeks i install 40 games, no problem at all. Will see...

Have you tried the game Hexsider? It supports two Hercules modes, one of them uses a similar tweakmode to Prehistorik. The other is a slower 'compatibility' mode.

Well... i put the Winbond again on the 286... i start prehistorik to check that the problem with prehistorik persists... and yes, the image was flickering

Next i run HEXSIDER with the 2 Hercules options

Hercules 1

Hercules 2

No problem at all

fede2222 wrote:

... The monitor has potentiometers to adjust h-width and v-height, i assume the third may be h-sync/refresh/frequency.. who know […]
Show full quote

Scali wrote:

The difference should be within the margin of error, but perhaps that one monitor is very sensitive. Even so, I'd expect it to have problems with more games then.
Does the monitor have any kind of horizontal controls? Like h-width or h-hold or such? If it does, perhaps you can tweak them a bit, and it may make the image stable.

...
The monitor has potentiometers to adjust h-width and v-height, i assume the third may be h-sync/refresh/frequency.. who know?.. but is blocked..

I tried tweaking with the potentiometers, they are H-pos and V-pos. To center the image at the screen.

First before make the tweak i ran prehistorik to check the image flickering, and yes, flickering

Then tweaked the H-pos and V-pos, because the image was centered already the only thing i do was move to left and move to right again... AND!!

It stabilize the image... i can't repeat the flickering.. and i tried.. 😜... now is working with the Winbond too.

RARE computer things... 😖

fede2222 wrote on 2016-06-13, 01:49:

RARE computer things... 😖

fede2222 where are you, last visited in 2018...
I am currently checking out some hercules-stuff on my Schneider Euro-PC with MM12.

My current targets:
- Ripping all unnecessary files out of any software that is not needed in order to run hercules. (making most usage of the limited space)
- Checking what cga-emulator is best the cga-only titles (which will include pc-booters)

Man that's fun with such a limited machine... 😀