video out disturbed on 1040STE

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Retro freak
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video out disturbed on 1040STE

Post by fbaldassarri »

Hi Folks,
recently (and suddenly) I encountered the following problem on my 1040STE.

I uploaded a quick video

As you can see my video output is disturbed... It is not the SM124, as I have more than one, and I tried with multiples monitor... same issue: so it is definitely a problem of the video output on STE.

It seems the TOS and GEM are loading normally. I can barely see the cursor and the desktop (icons, upper bar, etc...); but without the correct vertical and horizontal syncs.

Do you know what could be? :shrug:

Thanks in advance,
Atari 1040STE, Atari 520STFM, Commodore 64, Commodore 64C, Commodore 64G, Commodore 16, Commodore Plus/4, Commodore Amiga 500, Commodore Amiga 600, Commodore Amiga 1200, Commodore 128, IBM PS/2 Model 30, Olivetti PCS 86... etc etc etc...

Atari User
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Location: Minden, NV USA

Re: video out disturbed on 1040STE

Post by 6BQ5 »

So, you tried multiple monitors all show the same issue.

Forgive me for not knowing more about the monitor ... but, can you change the cable?

If not then can you try a ST DIN -> VGA cable? Modern VGA monitors work in monochrome because the sync frequencies are higher.

If VGA monitor also does not work with ST->VGA cable then something is definitely wrong with STe, even if it is simple problem of poor contact somewhere.


Atari 130XE
Atari 1040 STe

Atari Super Hero
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Re: video out disturbed on 1040STE

Post by siriushardware »

I am wondering if the machine is stuck in low resolution even when you have a mono monitor connected to it, due to a fault on the 'mono sense' input on the monitor socket.

Do you have a standard definition RGB monitor or TV with RGB-in, along with a suitable connecting lead? If so, try it to see if it is working normally in low and medium resolutions. Alternatively, try viewing the low resolution output on a TV, via an RF lead.

There's a simple check to find out whether the 'mono sense' sensing input is working. With the machine on, booted, and no monitor connected, make a wire link connection between pins 4 and 13 on the monitor socket and leave it connected. The moment you make the connection, the STe should reboot because it has detected a change of monitor from 'Not Mono' to 'Mono'. Give it time to finish rebooting, and then remove the connection - the machine should reboot again because it thinks the monitor has been changed from 'Mono' to 'Not Mono'.

If the machine does not reboot when you do this, it probably means the mono monitor sense input is defective, leading the computer to think that it always has a colour monitor plugged in, even when you plug a mono monitor in.

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