I will do it tomorrow - XT is back at the office. I want to make sure I will send you the exact version I am using.

OK I did some testing and what I think is going on is that the IBM CGA cannot trigger the mce2ega's composite emulation correctly, maybe the pattern is slightly different, maybe my card is to blame maybe the system, etc.
I am using an old version IBM CGA that I bought unused and sealed a couple of years ago. The host system is this: Hyundai SUPER-16TE xt clone: restoration and info

Here is what is happening with both 1988 and 1989 versions of Maniac Mansion - both versions with composite mode activated and mce2vga in composite mode:

in both situations mce2vga just displays a slight blurrier image of the RGBI screen when the composite emulation is activated - at the same time a direct composite connection to an lcd-tv works as expected

So is it the games? Nope. I jumpered the Prisma EGAMAX860 to CGA mode and installed it in the same system. The card does NOT have a composite output so in the following pictures you can see the mce2vga in RGBI and composite emulation modes:

So mce2vga composite emulation works with the Prisma card and not the IBM one in Maniac Mansion.
I installed the IBM CGA in my 386DX40 build, I have the same behavior in mce2vga composite emulation: KQ1 is OK, MM is not.

Is there any sense to that? I mean KQ1 is OK with the IBM cga, the mce2vga composite emulation works fine. What's so special with Maniac Mansion that triggers this behavior? 😕 😕 😕 😕

Just want to say thank you to all those involved in this project. I'm looking forward to the final product.

Just a question that I wish to raise about the composite mode emulation.
What is the rationale behind having composite emulation on this converter?
Wouldn't it be easier to just connect an RCA cable to the composite out on the graphics card and connect it to any monitor or screen with a composite input?
Isn't the main goal to convert an RGBi CGA/MDA/EGA output signal at a lower horizontal frequency (that is not supported by modern monitors) to an output signal that is supported by modern monitors?

I'm not criticising the project or the features but, merely trying to understand the benefits of the composite emulation.

There are reasons to have composite emulation:

- you don't need a 2nd monitor just for the games that support it
- it is a problem in PAL countries where a ntsc-composite signal will display in b/w in older crt sets
- you don't need an original IBM CGA to get correct colors in composite mode
- a great bonus for CGA users
- other I can't think of atm 🤣

I dig up my systems and I tried an original IBM XT with a second original IBM CGA, this is what I am getting with the mce2vga composite emulation in the 1988 version of MM (didn't bother with 1989 version as I only have floppies to work with the ibm xt).
MM looks 50% correct this time, KQ1 again is fine

also the colors could be off, instead of magenta you get red.

or it is mixing intensity: you get bright magenta and dark cyan that could be other explanation.

keropi wrote:

There are reasons to have composite emulation: […]
Show full quote

There are reasons to have composite emulation:

- you don't need a 2nd monitor just for the games that support it
- it is a problem in PAL countries where a ntsc-composite signal will display in b/w in older crt sets
- you don't need an original IBM CGA to get correct colors in composite mode
- a great bonus for CGA users
- other I can't think of atm 🤣

Thank you for the feedback - this clears up a couple of misconceptions I also had about composite mode.

^ it's a nice bonus in the end and can give some games a nice graphical boost

@retrocanada76
if there is more info/tests I can provide please ask as this is weird... Also testing MM in several systems I can't say it's the best-written game... it certainly has bugs especially with the keyboard routines judging from what I experienced. You are supposed to be able to quit with CTRL+C for example, a couple of times this did not work for me and all I got was the ^ character displayed on the top part of the game - no exit. I had to reboot my pc 🤣

the 1988 works in my CGA card. As I told you: either you get wrong colors or irregular lines due to different clock pixel. can you generate the color bars on this one ?
and which card is that ? can you take a picture of the card ?

also this game runs beautifully in my new Tandy 1000 EX 😀 the only interesting 16 color game that fits into one 360K floppy...

For the picture I can see your magenta if somehow off. See the cyan/black/white patterns work, only when mixing the magenta that it does not work. So I believe that:

cyan, white is low intensity and magenta is high (because it seems really bright) or
cyan, white is high intensity but magent doesn't. In this situation the magenta would always fail.

But that means something wrong, terrible is happening on your board, like shorted pins on the DB9 connector or so.

Just check if the red pin is shorted to the I pin... that would explain....

then run the checkit video test, check if you can see the low/high intensity difference on the magenta 320x200

^ I will pull out of storage my NTSC 1084 monitor and do a proper test of the card. I have some pics from when I got this one - it was bought new and specifically so I could get proper composite colors with my XT-class system.

I also took some pics back then when I acquired and repaired the NTSC 1084 monitor (it was quite a find because we are PAL land)

You can't get more original than this IMHO. The 2nd system I mention above is the IBM 5155 portable that also has an old-version original IBM CGA card inside as expected.

Maybe something happened on the meantime though, I will report back tomorrow.

A DOS guru also told me that Maniac Mansion's composite support is really bad so it's not a great example to show so many pics of.

Just to clarify for anyone else reading this, I post all these pics only to find out why I get these weird results with Maniac Mansion and original cards, not expecting proper and correct colors because they aren't really implemented. The converter DOES WORK PROPERLY with games like King's Quest 1 or even Commander Keen composite patch - I posted pics above.

retrocanada76 wrote:

Just check if the red pin is shorted to the I pin... that would explain....

then run the checkit video test, check if you can see the low/high intensity difference on the magenta 320x200

I decided to use a dedicated CGA/EGA monitor, the Hyundai HCM-1402 .
The Checkit photos are not good since my camera can't take good pics of it (I think it's the huge black area that affects color balance, it has an issue with this situation as apparent from the mda pics I posted some time ago) but the CGACAL one has no such issues. I can see a clear difference in magenta/light-magenta on the checkit tests, it's all normal.

I don't believe there is something wrong or shorted on the card it all checks out. So I followed the advice of the dos guru 😊 and tried other games that use the same mode as Maniac Mansion: Mode 4 320x200 4-color with color burst ON

Left is the composite output , right is the mce2vga in composite mode

Lost Tomb:

Dino Eggs:

Robo Odyssey:

So basically Mode 4 320x200 4-color with color burst ON can't be displayed with the mce2vga's composite mode emulation when using my old version IBM CGA cards.

^That's disappointing. I have an IBM CGA new in my Turbo XT which i'm planning to use a lot with the converter. I wanted to avoid another TV/monitor just for composite.

No it's not that disappointing Carlos - that's not the "proper" color composite mode! See my other pics on this thread, for example King's Quest 1 and KEEN4 composite patch both work perfect!
Maniac Mansion is a mess with it's composite mode anyways, keep that in mind.

well I cannot explain. Except that the pixel columns some look ticker than others. The composite is based on 4 pixels patterns like cyan-cyan-black-black (as seems if it was 640x200) but if you card generated them as cyan-cyan-cyan-black than it would fail. You need to take a picture of the maniac mansion patterns on your CRT monitor.

Also I noticed your CRT monitor seems to have the blue component off, look the white text has a blue drop shadow. Is it a camera effect ? Also between cyan and magenta there is a white separation.

I will take some good pictures of the mm patterns.
I will also re-check for that blue shadow you mention but I am pretty sure it's just the camera. When I tried to photograph the other checkit palettes I had real trouble with green, although it was nice on the crt the camera picked it up as a completely different color , a weird tone of light blue with a touch of green....

I have uploaded some pics here: http://www.mediafire.com/file/tk8g183viai60tf … a-comp_pics.rar
RGBi/Composite shots are from the same monitor - a NTSC 1084S-P that accepts both ttl and composite and you can switch on-the-fly with a front button.
Take into account that these being crt shots colors will be somewhat off 🤣

I don't know about CGA monitors but look the M from Mansion, right in the middle of it you can see a ticker magenta column. This should be one pixel wide, but somehow it seems larger. You can see this pattern all over the image.

Well, as you can see the monitor does display a working composite image - the RGBi shots are what you see if you make the monitor display ttl when the game is switched to composite mode (obviously in RGBi mode the image is way more clear).
Unless both my IBM CGA cards are somehow defective I would guess that's what they display in this specific screenmode and because the monitors back then where analog it didn't matter to them.

Maybe someone else more knowledgeable on this can shed some light... 😀