VGA scanlines?

[pawaller]

Hi forum,
Please can I ask for some help from your collective wisdom?

I while back I acquired an 1040STFM to relive my formative years :-)

The 1080p LCD monitor I am using does seem able to display all 3 graphics modes but I am seeing vertical "scan" lines across the whole display.

scanlines.JPG

Unfortunately I do not have access to another monitor which works with the ST's output.

It is definitely more noticeable when displaying darker colours but I can see it is there even with the standard desktop.

I have tried 3 different cables including the EXXOS ST2VGA board but they all show the issue.
I've tried adding inline resistors to the R,G,B and V sync lines.
I've recapped the PSU and also tried a bench 5V PSU ( using Gotech so 12V is not needed).
I've also tried going through a VGA to HDMI box but I see the same results.
I've reseated the Shifter chip and cleaned its contacts.

Could there be something else on the motherboard causing this or is it purely a video hardware issue or is it my monitor?
Do I need to go down the OSSC route to get a better output?

Any advice would be appreciated.

Cheers
Phil

[stephen_usher]

Unfortunately the noise on the video is just a fact of life with these old machines.

LCDs show the artefacts more as they have discrete brightness levels but you can see it on the original CRTs if you really look.

[rubber_jonnie]

@stephen_usher is right, it's just the way a lot of these machines are, especially when used with LCDs.

I use my Mega STE on an LCD screen and got rid of a lot of this by tweaking the brightness and contrast until it cleared up and I'm sure some people have said to try and adjusting the dot clock on the display.

[Steve]

You can fix it with one of these: https://www.exxosforum.co.uk/atari/store2/#0267

More info: https://exxosforum.co.uk/atari/last/VIDEODAC/

[pawaller]

Thanks all for your prompt replies.

I did play around with the monitor settings as best I could.

Don't remember it being an issue back in the day using a CRT monitor but those were simpler times :-)

Thanks for the links, interesting read about what's been tried, to improve the video quality.

Will ponder if it's worth my while going ahead with DAC upgrade , I'll see how long the nostalgia lasts before investing in one and digging out the soldering iron.

Cheers
Phil

[dgw]

Most likely barking up the wrong tree here, but do ferrite sleeves make any difference or are they just for EMR? I notice my old monitors leads have large ones whereas modern VGA leads small or none at all.

[rubber_jonnie]

Most likely barking up the wrong tree here, but do ferrite sleeves make any difference or are they just for EMR? I notice my old monitors leads have large ones whereas modern VGA leads small or none at all.

I tried some with my C128 and they didn't make any difference for me, however they are cheap enough to give it a try.

[pawaller]

I am slowly getting used to the scan lines being visible :-)

Has anyone got one of these OSSC units? Would investing in one get rid of the lines completely??

Thanks
Phil

[rubber_jonnie]

I am slowly getting used to the scan lines being visible :-)

Has anyone got one of these OSSC units? Would investing in one get rid of the lines completely??

Thanks
Phil

I did get a great picture from my ST's via OSSC, but I used SCART and only ever used lo and med res. Be aware that you might, as I did, get an awful PSU with my OSSC that injected interference on screen.

Simple enough to swap out though.

Only thing is that they aren't cheap.

[pawaller]

Thanks , yep they aren't cheap!