NESRGB discoloration horizontal bar at top of screen

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honkbahh
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Joined: Thu Oct 05, 2017 4:31 am

NESRGB discoloration horizontal bar at top of screen

Post by honkbahh »

The short: There is a brownish horizontal discoloration bar at the top of my screen in my nesrgb T.W. 2015 modded toploader.

The Long: I have an nesrgb (toploader) modded by a well respected person who I believe does great work. The mod is for composite, s-video, and rgb. The board is NESRGB14 T.W. 2015 and my output in the back is multiout. Both composite and S-Video work fine.

The cable I am using is the SNES csync multiout SCART recommended by the modder at the time of purchase (I have no idea what resistors are in it). I purchased two (one for my NES and my SNES) and both cables work just fine on the SNES, so at least the cable functions as it should (but maybe not the best choice for nes?). I also tried a sync on luma and it had the same issue.

Other Factors: I know its not an overscan issue, I am using an original power supply. I used to play on a framemeister and didn’t have this issue. However now I play on a PVM and now I see the issue. The framemeister is long gone, so I cannot go back and test it there again. Also, I have not gotten to play much in the last year, so I couldn’t for sure say that the transition is the main problem, although it seems likely and this would lead me to thinking i’ve got some type of resistor issue in my cable. However, I had a bizarre color issue (where the colors would flash to dark and very saturated) with this same mod a few years back, and I sent it back to be fixed. He replaced the color caps, which didn’t help, so then he says he replaced the entire nesrgb board in December 2016. This new board has the same model number as the old board (that color issue was also only present on rgb while s-video and composite worked fine). That makes me nervous it could be other something else and the PMV timing just coincidental, especially because it has been a good 6 months since I touched the nes.

Looking for thoughts and suggestions. Especially if the cable is actually this issue, could it have worked fine with the framemeister and not the pvm? Thanks!

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honkbahh
Posts: 4
Joined: Thu Oct 05, 2017 4:31 am

Re: NESRGB discoloration horizontal bar at top of screen

Post by honkbahh »

So I figured it out, and yes I'm a douche. It worked perfectly going directly into the tv, extron to tv, and gscartsw to tv, but not gscartsw to extron to tv. Then I found a small switch in the back of the extron that has 75 ohms and 510 ohms. I switched it to 75 and the issue was gone.

The nes itself directly into the extron had no problem with the 510, but through the gscartsw it needs to be at 75. So that's it...

It gives me a follow-up question. Everything else seems to function fine at the 510, but what should they be switched to? Thanks all!
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Syntax
Posts: 1827
Joined: Wed Aug 09, 2017 12:10 am
Location: Australia

Re: NESRGB discoloration horizontal bar at top of screen

Post by Syntax »

75 man :)

This had me stumped, I have never seen a shadow like that before.
Thankyou for sharing this with us.
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AndehX
Posts: 790
Joined: Sun Oct 18, 2015 11:37 pm

Re: NESRGB discoloration horizontal bar at top of screen

Post by AndehX »

Yes. Always 75 ohms for all consoles.
honkbahh
Posts: 4
Joined: Thu Oct 05, 2017 4:31 am

Re: NESRGB discoloration horizontal bar at top of screen

Post by honkbahh »

Thanks for the help. Not sure why they were at 510, because the user before me used it for games like myself. I'm also surprised it worked at 510 when the nes was directly connected through it. Oh well, I'm all good in the hood now. I'll switch all of them to 75 tonight... After I get the kids to bed, do the dishes... :cry:
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