STE VIDEO GHOSTING FIX

Various tweaks and fixes from video ghosting to audio fixes etc.
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exxos
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STE VIDEO GHOSTING FIX

Post by exxos » Mon Aug 28, 2017 11:34 am

 
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While I was developing my replacement AtariPSU I noticed the video quality improved immensely. However, I still saw some "ghosting" on the display which baffled me for a few hours. While ghosting can be other factors, such as bad video cable, ora bad LCD TV, for me the problem was on the Atari itself. On the left is the image before my fix, and on the right is after my fix. The left image shows ghosting to the right of the Atari Fuji and at the ends of the black box lines. While the ghosting is faint, it can still be seen clearly compared to the image on the right. Thankfully the fix is a easy one..NOTE - This mod was to fix RGB/scart issues and has not been tested with RF or Composite video signals.  

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Near the top left of the simms there is a yellow capacitor (C411) which needs more capacitance across it. The odd-ish thing is, R544 is actually a 8V regulator feed from the 12V rail. Normally I would have expected good regulation there, and it is, but its still not good enough to solve the video problems.

The results are...

1uF ceramic doesn't fully solve the ghosting problem.

10uF electrolytic probably 95% solves the problem.

47uF seems to work best, may improve a couple % with the 1uF in addition.

So a 47uF capacitor with the possible addition of a 1uF ceramic seems to fix this issue. Larger values than 47uF can be used, but I wouldn't recommend going below 47uF. Like I keep saying over and over in other pages on my site, you NEED low ESR capacitors otherwise "any old capacitor" will not work! Look towards Panasonic FR range of capacitors.

That's it! Enjoy your ghost free display :)

Another couple of images of ghosting issues (and fixed ) on a STE I wasservicing today..
 
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MSTE VIDEO GHOST FIX (WIP)

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I had a MSTE in for repair so I looked into solving the ghosting issue.It was only slight on this machine, so capturing a image proved difficult.However with soldering a low ESR 10uF capacitor across C506 as shown inthe above image removed what little ghosting I saw.

If anyone can verify this and take images on their own MSTE then it wouldhelp.

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redhawk668
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Re: STE VIDEO GHOSTING FIX

Post by redhawk668 » Sun Feb 11, 2018 6:54 pm

I did this fix too, on my 1040 STE. I am running my STE through a SCART/HDMI converter and this has improved the image quality significantly. Very happy with it.
Total retro nut, my collection: 1040 STE, TOS 2.06, 4 mb, CosmosEx - 520 STFM, TOS 1.04, 4 mb, Blitter, CosmosEx - 520 STFM, TOS 1.04, 4 mb - 1040 STF, TOS 1.04, 1 mb, Gotek - Amiga 1200 with Blizzard 1220/4 - Amiga 500 + ACA500 - Amiga 500 + TF530, 1 mb chipram hack.

Atari 8 bit: 800XL, stock - 600XL, Ultimate 1 mb, Sophia RGB - 130XE, 320 kb, Sophia RGB

Sinclair stuff: ZX Spectrum Plus - ZX Spectrum 48 kb and self built clones.

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Re: STE VIDEO GHOSTING FIX

Post by exxos » Sun Feb 11, 2018 9:37 pm

redhawk668 wrote:
Sun Feb 11, 2018 6:54 pm
I did this fix too, on my 1040 STE. I am running my STE through a SCART/HDMI converter and this has improved the image quality significantly. Very happy with it.
Nice one, thanks for letting me know!
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

BlankVector
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Re: STE VIDEO GHOSTING FIX

Post by BlankVector » Tue Feb 13, 2018 12:50 am

Hey, that's amazing :ugeek:

redhawk668
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Location: Netherlands

Re: STE VIDEO GHOSTING FIX

Post by redhawk668 » Tue Feb 13, 2018 9:15 pm

Another thing is, I’ve connected the HDMI converter to a VGA connector and connected it to a 5:4 ratio Acer AL1917 VGA LCD screen, image quality is great and it has built in speakers. So, basically the converter works as a scandoubler/scaler. I use it with all my retro computers not only my Atari ST’s. I got this screen for free and after gathering dust on the shelf, I decided to put it to good use. I am very happy with this screen ;)
Total retro nut, my collection: 1040 STE, TOS 2.06, 4 mb, CosmosEx - 520 STFM, TOS 1.04, 4 mb, Blitter, CosmosEx - 520 STFM, TOS 1.04, 4 mb - 1040 STF, TOS 1.04, 1 mb, Gotek - Amiga 1200 with Blizzard 1220/4 - Amiga 500 + ACA500 - Amiga 500 + TF530, 1 mb chipram hack.

Atari 8 bit: 800XL, stock - 600XL, Ultimate 1 mb, Sophia RGB - 130XE, 320 kb, Sophia RGB

Sinclair stuff: ZX Spectrum Plus - ZX Spectrum 48 kb and self built clones.

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Re: STE VIDEO GHOSTING FIX

Post by exxos » Tue Feb 13, 2018 10:24 pm

redhawk668 wrote:
Tue Feb 13, 2018 9:15 pm
Another thing is, I’ve connected the HDMI converter to a VGA connector and connected it to a 5:4 ratio Acer AL1917 VGA LCD screen, image quality is great and it has built in speakers. So, basically the converter works as a scandoubler/scaler. I use it with all my retro computers not only my Atari ST’s. I got this screen for free and after gathering dust on the shelf, I decided to put it to good use. I am very happy with this screen ;)
Nice :) why not post your setup with some screenshots over on this section viewforum.php?f=30 :)
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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