Atari 1040 STF SCART to GBS-8200 not working

[zezba9000]

So I'm trying to get my Atari 1040 STF (and eventually 520 ST) working on a modern LCD.

 

I've bought these...

 

ATARI ST QUALITY RGB SCART: https://www.ebay.com/itm/ATARI-ST-QUALITY-RGB-SCART-LEAD-TV-VIDEO-CABLE-2-METRES/321231353702

 

ATARI STe RGB SCART LEAD WITH STEREO AUDIO: https://www.ebay.com/itm/ATARI-STe-RGB-SCART-LEAD-WITH-STEREO-AUDIO-VIDEO-CABLE-2-METRES/390925970438

 

Use GBS-8200 GBS-8220 with VGA (15KHz support): https://www.ebay.com/itm/Use-GBS-8200-GBS-8220-with-VGA-15KHz-support-monitor-Amiga-Atari-Sega-SNES-etc-/232826060192

 

GBS-8200: https://www.amazon.com/gp/product/B078ZDTLBJ

 

There is nothing in the examples that shows anything special is needed: https://drive.google.com/file/d/1EKWLkn6dIlYVOv7d8ZDClqqRkY8HIjr1/view

 

------

But nothing works, the GBS-8200 just says no signal.

I'm using a both devices off the same 5v 2a power supply.

What am I missing?

Edited November 5, 2020 by zezba9000

[ParanoidLittleMan]

Pretty much complicated . Atari-RGB Scart cable, then that GBS passive adapter what only has Scart connector and couple other connectors (price 31.90), then GBS-8200 (22.99) .

Funny prices - passive adapter with cheap connectors and little cable costs more than converter with plenty of components ???

Hard to say what can be wrong. It should work if cables are OK, and on Scart RGB switch voltage is present (normally +12V from Atari video connector is used for) . Then that expensive passive thing actually only sends RGB and sync signals to GBS-2000 . 

I guess that problem can be right in sync signals.  Or maybe it is not set for GBS-2000 properly. Is +5V connected properly to board ?

And it is not specified for which Ataris this combination is good. Some experiences folks ?

 

[snarkdluG]

Does the extra scart board have any IC on it? 

 

The GBS82XX is not great out of the box. It also introduce lag. 

 

I think you need composite sync on GBS8200 to get it to work satisfying with Atari. And Atari doesn't have that on the 13 pin DIN connector. You only have horizontal and vertical sync (and composite video but that is not the same). 

 

Here is how you get composite sync otherwise.

 

 I would also use GBS Control on it to behave better. 

[zezba9000]

Ok Ill go over in more when i get time.

What is the best option to get Atari ST working on a modern screen?

[snarkdluG]

11 hours ago, zezba9000 said:

...What is the best option to get Atari ST working on a modern screen?

From expensive to cheapest;

Framemeister, OSSC, retrotink. 

 

But cheapest is not really cheap. 

[Chri O.]

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

 

More info in this post: Atari ST1040 and ST250 Display Issue

Edited November 6, 2020 by Chri O.
More info

[zezba9000]

23 hours ago, Chri O. said:

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

 

More info in this post: Atari ST1040 and ST250 Display Issue

 

Ok thanks. So the 74LS86 is "OR" gates?

 

So combined sync goes to PIN-S (aka C Sync) on the GBS-8200?

[zezba9000]

On 11/5/2020 at 12:28 PM, snarkdluG said:

From expensive to cheapest;

Framemeister, OSSC, retrotink. 

 

But cheapest is not really cheap. 

So you're saying this will work out of the box on a Atari 1040 STF & probably 520 ST?

https://www.retrotink.com/product-page/retrotink-2x-scart

[Chri O.]

22 hours ago, zezba9000 said:

 

Ok thanks. So the 74LS86 is "OR" gates?

 

So combined sync goes to PIN-S (aka C Sync) on the GBS-8200?

1. YES Exclusive OR Gate.

2. YES but you need to cut Hsync trace if installed inside the GBS8200 converter ( VGA input only ).   see pic.

[zezba9000]

Finally getting back to this. (Have to many projects).

 

So only have the green color channel hooked up in this test but its working.

Edited December 11, 2020 by zezba9000

[zezba9000]

Have full color working now!

I may look into adding a VGA Mono switch option for the box I'm making.

 

So I had to modify the mixer diagram a little and got much better image stability.

Remove the resistor from PIN 12 & PIN 6 (leave resistor on PIN 13). Will test on my Atari ST 520 but got way better image on 1040 doing this (I wonder if this holds true for others).

 

Didn't know this level of 3D was possible on a 16bit computer of this age.

[Chri O.]

Cool so finally you got this going ?

I am also busy with bunch of other project, trying to port STM32 Arm Cortex ACSI2STM Atari hard drive emulator to Teensy 3.5 MCU https://github.com/retro16/acsi2stm.

19 hours ago, zezba9000 said:

Didn't know this level of 3D was possible on a 16bit computer of this age.

http://www.atarimania.com/game-atari-st-armour-geddon_11097.html

Try this game I spent many hours with my brother in multiplayer using two Atari STs and RS-232.

Edited December 12, 2020 by Chri O.

[zezba9000]

And tur-la-de-da its done!!!

 

I added a switch for Color and B/W modes as you can see in picture.

 

 

Now I got the color video signal a WAY more stable by tweaking some stuff even more on the mixer.

* No resistor on HSync-Pin-12

* 10k resistor on VSync-Pin-13

* 10k resistor on CSync-Pin-6

* No resistor on Pin-5

 

Also added a 10k resistor on the audio GND as it seemed to help interference noise.