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Faint vertical lines (shadows) on a CRT

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First post, by SheikYerbouti

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It's been a decade since I had my last CRT, so I don't quite remember what's normal. But I just bough a new in box Samtron E78 (manufactured around 2003) and upon turning it on, it works great, BUT there's these vertical shadows across the screen. Not on the screen itself but "behind" it. So now I'm wondering if that's just normal CRT behavious or is my monitor defective? It seems to work great otherwise.

Reply 1 of 10, by imi

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the only faint lines from CRTs I know are horizontal on trinitron screens, the stabilizing wires holding the aperture grille.

do you have a photo showing the effect you mean?

Reply 2 of 10, by SheikYerbouti

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imi wrote on 2020-05-28, 15:05:

do you have a photo showing the effect you mean?

It looks something like this (click to enlarge):

14843383.t.jpg

Not the best picture, sorry about that. I also noticed, that the lines don't appear until I connect my computer to it. While it's just displaying the No Connection -box, it's perfectly black otherwise. My graphics card is a cheapo Avance Logic ALG2302.A.

EDIT: It's similar to what this monitor this showing (not my monitor, just some random for sale CRT):
439832534-orig.jpg

Reply 3 of 10, by imi

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the second picture looks fine to me, that's just moiré from the camera.

probably just noisy VGA ouput from the card, you could try turning down brightness to see if that helps make it disappear.

Reply 4 of 10, by SheikYerbouti

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imi wrote on 2020-05-28, 15:43:

the second picture looks fine to me, that's just moiré from the camera.

probably just noisy VGA ouput from the card, you could try turning down brightness to see if that helps make it disappear.

Thank you, I'll start scouting for a better graphics card!

Reply 6 of 10, by imi

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true, I'd try that before changing the card ^^

Reply 7 of 10, by SheikYerbouti

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cyclone3d wrote on 2020-05-28, 17:50:

Could also be a crappy VGA cable if it isn't built into the monitor itself.

Good call, I'll check that too!

Reply 8 of 10, by psychz

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Have had this happen on an LCD too (SyncMaster 720), output from my 486 (CL-GD542x VLB cards, Pine Technology iirc). At first I thought the card was bad, got a replacement, the second one gave me similar results. It got fixed after replacing the caps on them!

Stojke wrote:

Its not like components found in trash after 20 years in rain dont still work flawlessly.

:: chemical reaction :: athens in love || reality is absent || spectrality || meteoron || the lie you believe

Reply 9 of 10, by Tiido

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The stuff I saw in the photo looks like digital interference from video card itself. Placing some good capacitors to RAMDAC power lines on that card can probably cure this problem.

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Reply 10 of 10, by SheikYerbouti

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Tiido wrote on 2020-05-31, 02:15:

The stuff I saw in the photo looks like digital interference from video card itself. Placing some good capacitors to RAMDAC power lines on that card can probably cure this problem.

Good to know, thanks!

I also noticed, that the lines don't appear when I choose a resolution of 1024x768, only on 800x600 and lower.

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