Atari 1040ST [13-pin] AV Out Question

[raoulduke]

Step 2... I'm assuming you cannot just connect a single pin of the 1040ST's output to a single composite cable and run it to a TV/RF modulator to test, right?

I'm about to order the only adapter I could find [which is $20 for me - it's in the UK], and I'd just like to clarify that I didn't confirm that the machine's output is somehow scrambled. Through the RF I could clearly see signal outputs but nothing resembling a coherent picture. I'm hoping that's because I was attempting to isolate piecemeal outputs [and then describe it all poorly in layman's terms].

** http://atariage.com/forums/uploads/monthly_10_2010/post-6701-128665872766.gif

 

[g4ugm]

You are probably better asking on an dedicated Atari Forum...

1) Are you talking Mono or Color output?

2) The mono is not TV compatible and is activated by grounding (Or do you pull it to 12v) the appropriate pin on the 13-pin plug

3) There is no composite on the 13-pin unless the machine came with a modulator installed (So an STFM)

4) The output should be standard TV sync rates analogue RGB. In the UK most TV's have RGB inputs via their SCART socket so a simple cable is possible. In the use most TVs have "component" YPbPr inputs. There appears to be an outline circuit to convert here:-

http://www.linear.com/solutions/1312

but I have no idea if its any good. A UK adaptor may not work as a US Atari will be set for NTSC scan rates and a UK adaptor will expect PAL scan rates.

 

[raoulduke]

You're right of course. I actually went a different route on this... I wish I'd paid closer attention to the fact that only 6 pins are actually used... could have saved some time. So I should be able to solder this together after dinner and I'll report back my results.

For posterity: 1) don't care; 2) don't know; 3) didn't come with a modulator [I fed it through to one, but I clearly don't understand enough of this (which is why I'm only answering in a cursory manner - I clearly lack basic knowledge)]; 4) our TVs (or I guess the TVs I plan to use) have both.

This issue has come up before and people said no re: TRS-80 MC-10 (and I still disagree) but my Apple Color Composite monitor should be able to handle these things (idk about hi-res...) and according to the manual it supports both PAL and NTSC, but I appreciate the heads up on standards and that's a good point. Still, I think if my VGA cable works... screw it. It will end up having cost me nothing and I still have to buy a mouse.

*The picture's a little small, I cut the VGA cable and put 13/15 pins in each slot through a piece of cardboard (so I can pull them in and out) but since it only needs 6 pins that makes this way more manageable. I plan to solder the 6 cables (1 of which is already twisted into a single black cable). As I say... seems simple but I'll report back.

 

[raoulduke]

No... wait, the adapter is purely passive; I don't think the standard should matter, actually. Maybe my logic is flawed there.

Also, the cable vendor, and I can't guarantee they'll do this for everyone but I suspect they probably will [http://www.ebay.com/itm/121660936784, offered to send me a 13-pin plug (just the plug) for £1, so that'll do better than whatever I can rig up on that end; and that'll give me a VGA cable and a composite cable for $20; which is still a little more than I wanted to spend on this, but my cable - if successful - is not a good permanent solution.

 

[g4ugm]

If you check the listing that cable only works with the "M" Atari models (Atari 520STM, 520STFM and 1040STFM) so those with an RF modulator built in, not the SF. The Atari only has composite on the 13-pin connector if it has a modulator. So you can't that cable it with a Composite monitor like the Apple unless you hack it to accept RGB inputs. see:-

http://atariage.com/forums/topic/227593-atari-1040stf-with-no-video/

For composite the standard matters because they are different, so you would probably get a mono display with distorted color, but as you say you have an STF with no modulator, and only RGB its not so important. RGB will probably work, with some tweaking on any RGB TV standard analogue monitor, so Atari Color Monitor, or Amiga Color Monitor, or 3rd party such as Philips cm8833.

You may also need to care about mono/color. Most games only run in color. Some apps such as midi sequencers only work in mono because its higher resolution and for that the simplest solution is a VGA adaptor cable, but you will only get a MONO display and games won't work. If all you want to do is copy disks Mono is just fine.

Atari Video is a mess, especially in the USA where RGB monitors are uncommon...

 

[raoulduke]

Wait... now I'm a little confused. I assume RGB encompasses a broader category, but I assume by RGB here we're referring to my VGA hack (where the VGA picks up Red, Green, and Blue on the first three pins)?

Actually this is a pretty solid deal: http://www.nkcelectronics.com/13-pin-circular-din-connect.html - For me that's $3.49 for one. Well it's solid in that I don't want the $10 10 pack on Amazon, though originally I'd considered making 9 others at cost - I doubt there's the demand. And I doubt the eBay seller can beat that price.

It only booted once... not sure what's going on...

 

[g4ugm]

The Atari has three video display standards.

Low -> 320 x 200 x 16 colours - "TV" scan sates so 50Hz Europe 60Hz USA
Medium -> 640 x 200 x 4 colours -> TV scan Rates
High -> 640 x 400 x Mono -> 72Hz x 31Khz video

and most "Original" Atari monitors only supported either Color(low/med) or Mono(High). You could use and expensive MultiSync but most folks didn't.

By default you get "low" resolution, if you have disk with settings in when you boot you can boot to medium, if you have a high res monitor with the pin set in the interface you only get high.

As most SVGA monitors will sync to 72Hz x 31Khz or ther abouts you can display the Mono res with a hacked VGA cable. IS that what you are using?

The VGA hack usually only works with "high" but its rumoured (and I haven't tried it) that some TVs with a VGA input will let you feed 50 or 60Hz RGB video into the VGA port and display it. Might be worth a try!
more info here:-

http://www.atari.org/hosted/quickfaq/stfaq_1.htm

but it looks like you have it booting and display so I guess you know all the above

 

[raoulduke]

I'm using a hacked VGA cable that I'll formalize when the DIN 13 pin connector gets here. I guess it boots normally. It just takes a really long time. I only made a TOS disk and it boots to TOS from ROM, so without a mouse or more knowledge of the platform I'm not sure what's going down precisely. I would think especially with the disk in that it would boot immediately, and that makes me wonder if there's a drive problem.

But the VGA hack works using the pin diagram I posted I think in the first post.

 

[g4ugm]

ok wrong way round. You can move the mouse with ctrl or shift or perhaps something else + the cursor keys (I couldn't find a link).

Try formatting a disk in the ST and see if that speeds the boot process.

Some ST's ony have single sided (360K) drives. I think the quick way to check is to try formatting double sided. If it has then putting in a double sided disk will not speed the boot process.
It will try and read the wrong side and fail...

Only reason for a disk is to save desktop layout...