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Connecting Amiga to VGA monitor

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vladstamate

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Dec 2, 2012
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Orlando, FL, USA
I am sure I am neither the first nor the last to try to connect their Amiga to a modern-ish VGA monitor. I am trying to do this in 2 ways:

1) Using a 23pin DSUB to VGA cable connect directly to a LCD monitor. I have about 8 of them in my collected, tried about 3-4 and I get no image. I assume the monitors I have cannot sync to the signal coming out of the Amiga. I found this list here of monitors that could work: amibay So I can try obtaining some of them

2) Using a Gonbes device (GBS8200). That actually gives me an image on my LCD monitors. However the image jumps every other second, presumably due to sync issues. Now I think my problem is the fact that the Amiga is connecting to the GBS8200 via same 23pin-to-VGA cable and I think that is not right. Looking for videos online I see that people who got Amiga to talk to a LCD monitor via the GBS 8200 connect wires directly on the board (R,G,B, Sync and ground).

I guess I am looking for confirmation that what I think is indeed the problem.

The other issue is that it seems so DAMN HARD to find female 23pin DSUB connectors. Where do you all source them from?
 
I've had no trouble using adapters like this: https://amigastore.eu/en/207-amiga-rgb-to-vga-monitor-adapter.html
However, my use case was different: I used a VGA to RGBHV BNC breakout cable so I could connect it to a scan converter. Your Gonbes is also a scan converter, however I used both the H and V for sync whereas you might only be using H, or sync-on-green, or whatever. My suggestion is to explore more sync options on your Gonbes.
 
Hi your vga monitors can't sync to the 15khz signal from the amiga.

Using the gbs8200 it should work fine, you will need to feed rgb and composite sync to it. Using h v separated sync will not work (this is a design defect in the gbs8200).

The db23 pin is hard to source what i have done is cutting the last two pins to the db24 connector and work great.
Tutorial for the gombes : http://amigamodblog.blogspot.com/2012/06/amiga-500-scan-doubler-vga-converter.html

You can also use the composite output on the amiga for games, and on screen options your workbench configure productivity modes or the vga modes they are 31khz for desktop work. Of course if you run a game it will fall back to 15khz. An AGA amiga is necessary for this and probably a cpu accelerator (productivity modes and vga eat more cpu time).
 
If you already have a 1084 Amiga cable, usually a DB23 to DB9 connector you can also use that cable by getting the opposite gender DB9 and soldering the wire harness that comes with the GBS directly to that, or wires if you don't have the harness. The 1084 cable has the signals you need for the GBS. Then it is a matter of plugging in the DB9 cable to the 1084 cable and then into your Amiga and it should work.
 
Your idea is good actually. I do not know if my cable is the 1084 Amiga cable but I do have the DB23 to VGA cable. I will open that up and see what pins of the DB23 are connected to what pins of the VGA head and then like you said I can use an opposite gender DB9 which is much easier to source.
 
Another option that i've done with an Atari ST and my friend also used the same box with his Amiga (my amiga is a 3000 so it already has vga) is to use a SCART cable (the good kind with all the proper resistors) then use a specific SCART/HDMI converter. However, this gets you to HDMI, not VGA, if that matters? Heres the ST youtube link but I'm sure there are Amiga videos as well using the same box (I found a couple but they weren't english)... This is the only box i've found that works properly, because from what we can tell, it's using an actual decoder chip they use in TV's.

https://www.youtube.com/watch?v=pZrTISByUb4
 
ngtwolf said:
Another option that i've done with an Atari ST and my friend also used the same box with his Amiga (my amiga is a 3000 so it already has vga) is to use a SCART cable (the good kind with all the proper resistors) then use a specific SCART/HDMI converter. However, this gets you to HDMI, not VGA, if that matters? Heres the ST youtube link but I'm sure there are Amiga videos as well using the same box (I found a couple but they weren't english)... This is the only box i've found that works properly, because from what we can tell, it's using an actual decoder chip they use in TV's.

https://www.youtube.com/watch?v=pZrTISByUb4
Click to expand...

Yes I used this exact box on my Amiga 2000 and 500 and it worked flawlessly. I will make a video for your YouTube channel soon showing off the box with the Amiga. I used the box + a Sega Saturn RGB cable -- just cut the sega saturn connector off and soldered on a DB9 female connector. I then used the normal Amiga 1084S cable into it.

The nice thing about this box is it perfectly supports PAL, NTSC and NTSC 4.43. It is pretty darned sharp and with no interference or lines (like the GBS apparently gets) -- can output various these resolutions over HDMI/DVI: 800x600, 1024x768 and 1280x1024. THen also 720p and 1080p (the image is stretched to takeup the full size.) It's not nearly as good as VGA on a flicker fixer (pixel perfect) but this is pretty darned good. I ordered one recently from Chine for just a hair over $20 USD shipped. You can use a HDMI to DVI adapter to use it with a regular old LCD screen.

It also supports Composite input (via SCART pin 20) but does not support S-Video or Component. Composite input is pretty great quality too.

Here are some pics of the entire thing including RGB on the Amiga, Atari ST and composite with an Apple II.
https://imgur.com/a/nhfjKWw
 
misterblack said:
Yes I used this exact box on my Amiga 2000 and 500 and it worked flawlessly. I will make a video for your YouTube channel soon showing off the box with the Amiga. I used the box + a Sega Saturn RGB cable -- just cut the sega saturn connector off and soldered on a DB9 female connector. I then used the normal Amiga 1084S cable into it.

The nice thing about this box is it perfectly supports PAL, NTSC and NTSC 4.43. It is pretty darned sharp and with no interference or lines (like the GBS apparently gets) -- can output various these resolutions over HDMI/DVI: 800x600, 1024x768 and 1280x1024. THen also 720p and 1080p (the image is stretched to takeup the full size.) It's not nearly as good as VGA on a flicker fixer (pixel perfect) but this is pretty darned good. I ordered one recently from Chine for just a hair over $20 USD shipped. You can use a HDMI to DVI adapter to use it with a regular old LCD screen.

It also supports Composite input (via SCART pin 20) but does not support S-Video or Component. Composite input is pretty great quality too.

Here are some pics of the entire thing including RGB on the Amiga, Atari ST and composite with an Apple II.
https://imgur.com/a/nhfjKWw
Click to expand...

I have seen similar boxes in action the main problem they have is that they take all modes that are 240p (amiga 640x200 320x200 etc) atari st low and med modes like they are 480i signals and then deinterlace them the result is not good at all to play games.
 
I finally fixed the problem by making my own DB23 female cable (by using a Dremel on a very cheap and easy to get DB25 connector) and then I soldered on the that DB23 to connect R,G,B Sync and ground with a special cable to the GBS8200. The GBS then did the scaling and syncing and now I can use ANY VGA monitor I want with my Amiga.
 
soviet9922 said:
I have seen similar boxes in action the main problem they have is that they take all modes that are 240p (amiga 640x200 320x200 etc) atari st low and med modes like they are 480i signals and then deinterlace them the result is not good at all to play games.
Click to expand...

So this box is a little different. It is basically a LCD TV SOC in there and instead of connecting to a LCD panel, it uses a HDMI transmitter instead. It is definitely not handling 240p perfectly, but 60fps animation seems pretty nice without major issues. Interfaced video signal does show signs of the deinterlacing but I don't really see major artifacts on the 240p. When I'm home I'll run some PlayStation games into it and see how things look. I played a few ST games on it and they all seem to look fine and run at 60fps.

If you can recommend maybe a good Amiga demo to try that will really expose the processing issues, it would be helpful.

Unrelated, I love your avatar pic. I'm just rewatching Babylon 5 for the first time since it first aired. Such a good show although it looks so dated now with the super 90s looking everything. :)
 
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