Atari ST to Commodore 1084s monitor

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Re: Atari ST to Commodore 1084s monitor

Postby calimero » Wed Jan 11, 2012 2:56 pm


I make composite cable but I did not know that PIN 2 on DIM 13 already carry complete composite signal :/

(I hope to connect RGB lines + H + V sync to get composite video signal and to check if I will get RED color...)

anyway, this composite is quite good - it is not sharp as separate RGB + sync (I would say that difference in sharpens is double!) and there is some small ghosting but it is quite good for games...

now I will need to buy another Commodore monitor for Amiga 500 ;)
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Re: Atari ST to Commodore 1084s monitor

Postby wongck » Wed Jan 11, 2012 3:49 pm

calimero wrote: I did not know that PIN 2 on DIM 13 already carry complete composite signal :/

Not all models do.
Check the AF wiki or the FAQ links at the wiki.
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Re: Atari ST to Commodore 1084s monitor

Postby Dal » Wed Jan 11, 2012 4:06 pm

Any model with a modulator outputs composite on pin 2
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Re: Atari ST to Commodore 1084s monitor

Postby Nui » Wed Feb 08, 2012 6:56 pm

Do I need a modulator to connect an ST to a 1084S or does it also work with my STF?

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Re: Atari ST to Commodore 1084s monitor

Postby retango » Sun Feb 21, 2016 3:35 pm

First of all thanks a lot Anemos for the tip!!
I tried the connection in post 1, and it did not work for me (I might have made some mistake when soldering the cables, so it may still work). However, I tried another connection, and it DID work!!! Atarti 1040 STF to Commodore 1084 S-D2 (with Female DB9 in the monitor). Instead of connecting Atari ST Pin 2 to DB9 Pin 7 (V+H sync composite), I connected Atari ST pin 9 to DB9 Pin 8 (H-Sync) , and Atari ST Pin 12 to DB9 Pin 9 (V-Sync).. And it worked!
In practice, instead of building a new cable (after my failed try), I used an Best Electronics Cable ( and built a DB15 to DB9 adaptor adaptor with these terminal breakout connectors:

I Connected
DB15 ----> DB9
Red (Pin 1) ----> Pin 3
Green (Pin 2) ----> Pin 4
Blue (Pin 3) ----> Pin 5
H Sync (Pin 13) ----> Pin 8
V Sync (Pin 14) ----> Pin 9
Ground ----> Pins 1,2, Ground

I did not use the resistors mentioned by Anemos, although maybe there are some in the Best Electronics cable..
Thanks again and good luck if anyone is trying this!

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Re: Atari ST to Commodore 1084s monitor

Postby walterg74 » Mon Aug 29, 2016 10:31 pm

So since someone already revived this, this year...

Having problems with an STf and a 1084S-D2...

Tried an atari/scart + scart to db-9 adapter and nothing. I assume this is because the stf has no video on pin 2 where usually sync is taken from, and seemingly not even just sync.

I tried another cable I had, the famous atari/philips cable. With this one, I get image but it rolls vertically a lot!
Mi tried doing a continuity test to see what pins were connected, and it seems h-sync and v-sync are both connected frlm/to the correct pins, so jot sure why it rolls. Also, pin 2 was connected as well to the c-sync pin of the db-9 (probably to cover all models?).
Could it be that there is *some* signal from pin 2 that is causing issues? Cable connectors are not removable and I don't wanna break it.

Anyone know what it could be and if there's any way to fix before attempting to build a cable on my own from scratch..?

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