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Atari ST1040 and ST250 Display Issue

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Greetings All !!


I have picked up a monitor cable (DIN 14 pin I believe) that goes from the ST computers to a VGA connector. I also have an arcade VGA input convert the converts the 15khz to standard VGA. The convert I have and monitor works as this same setup works perfectly for my Amiga 500. However, when I use this cable with my ST1040 or ST520, I get a "rolling" image like there is no vertical sync. I have checked both the H and V sync pins on the cable and both have continuity. I have attached a picture of the image. I am thinking the cable must be faulty as the Amiga 500 cable and this same setup works great. I also have a recommend VGA to HDMI converter that was shown in a youtube video working with a similar cable but the HDMI display will not even get an image. Any ideas is greatly appreciated !!! Thank you !!!




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17 hours ago, TGB1718 said:

I had similar issues with a VGA monitor, turned out to be a poor solder joint on the ST video socket,

just a re-flow on all the solder points resolved the problem.

Thank you but I don't believe that is my issue has both my 1040ST and 520ST have the same exact issue. 


1 hour ago, Chri O. said:

Well in my case I had no luck with GBS 8200 VGA Arcade Converter until I build video sync mixer for Atari 1040 STE (H sync+V sync to (C sync))


Chri, I think that is what I need to do ! I have the exact same GBS 8200 board !! I'm just curious because the person on eBay I purchase the ST to VGA cable from has sold tons of them and when I explained to him what was happening, he thought the cable he sold me might be bad ? Anyway, I would love to try what you did !! I also have the esynic VGA to HDMI converter which also didn't work. It was recommended by this youtube video below. His video shows separate H and V sync which is how the cable I have is wired. He did mention that the monitor is dependent on what signal you send it and I know my HDMI monitors don't support 15khz. What do you think ?


1 hour ago, Chri O. said:



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19 hours ago, macjax said:

I have the exact same GBS 8200 board !!

When you mentioned the Arcade VGA converter I had a hunch, welcome to the family. ?

On Atari STFM (TV Frequency Modulatior) models you can probably just modify the cable (disconnect pin #9  and connect to pin #2) but for Atari ST and STE you need the video sync mixer.

NOTE: this is untested as I don't have any Atari STfm.


About the esynic VGA to HDMI converter, 15khz and HDMI will never work I can tell you this much.


Atari Monitor pinout.gif

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Ohh if you do get this going get the Wemos D1 Mini Arduino Development Board ESP8285 for the next hack if you want the perfect picture quality and GBS 8200 board. ?

https://shmups.system11.org/viewtopic.php?f=6&t=52172  good luck reading this it took me two days ?

GitHub link: https://github.com/ramapcsx2/gbs-control

Edited by Chri O.
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  • 3 weeks later...

With this board, are you able to get all three ST resolutions?  I know that the pin out for the color monitors and mono monitors were different.  

The mono pin out had all three red, blue, green lines attached together with a mono detect pin.



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Hey djglish, actually no and a good question. I was only able to get Low and Med resolutions. High was greyed out. Now I don’t know exactly why but just figured the sync combiner couldn’t handle it ? Not really sure. Maybe someone here can advise ?

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The video cable must be only designed for the color mode.  I made a cable, years ago, with a switch that let me switch between the two modes.  It worked well on the multisync monitor that I had at the time.  Unfortunately that monitor bit the dust.  Best Electronics makes a cable for this.  The vga mono signal will work on a standard vga monitor since it is a 60kHz signal.  


I bought a little vga to HDMI box that let me upscale to an HDMI TV.  It gives a good picture.  It's a little klunky since I go from my special cable to a vga cable to the HDMI box to a HDMI cable and then to the TV.  



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