Genesis Model 2 vertical bars in S-Video using JNX Genesis/AES S-video kit.

Finch

Hardened Shock Trooper
10 Year Member
Joined
Jul 14, 2009
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Modded my Genesis Model 2 using the JNX S-Video mod kit that is also used for the AES. While not all Model 2's use the Sony CXA1145 encoder, mine does, so the mod works fine. Guide link. Only problem is that I am getting dark vertical bars across the image. They mostly show up on medium brightness backgrounds and other large sections of solid color, but it's quite noticeable. Anyone know a fix for this? They never really bothered me before on my previous TV or my PVM, but on my new TV they are much more visible. You can actually see them present on the example screenshot for Columns that is included in the JNX guide.

Ugly original S-Video:, note lack of vertical lines in the teal color in the title.

Modded S-Video: Vertical lines are now present in the teal color, although everything else looks way better than the original.
 

Finch

Hardened Shock Trooper
10 Year Member
Joined
Jul 14, 2009
Posts
431
Samsung HL61A750 DLP rear projection. They were visible on my previous TV too, a Sony 34XBR910 CRT, and they are also there on various LCD screens I've used. Only place I don't really see them is a 14" PVM....but that is probably just due to the screen size.
 
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Xian Xi

JammaNationX,
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Dec 1, 2005
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Got pics? I'm guessing it's an upscaling artifact.
 

NoAffinity

Kuroko's Training Dummy
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Mar 20, 2017
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Unfortunately, mods, upscaling, any improvements to the genesis tend to bring out the jail bars. The cxa1145 is the primary culprit for causing them, but not the only culprit. There is a ton of noise generated by the genny pcb itself, some worse than others. I've got 2 hdg model 1's. Both look and sound great, especially when line quintupled through the ossc, but both have pretty noticeable jail bars. One is rgb bypassed, the other is stock. The stock one is slightly worse, but even with the rgb bypass on the one, it's only a slight improvement. There are additional basic solutions (check retrorgb.com for guides), and in addition, the way you installed your mod may be introducing noise to the analog video circuit due to proximity to the origin of the noise. You may have already done this, but keep the wires for your mod as short as possible and components of the mod away from bigger chips, the cxa1145, and any oscillators. Easier said than done... :)

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incrediblehark

New Challenger
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May 3, 2006
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it seems like it really varies system to system too... it seems to depend on the circuitry of the systems causing interference. My Genesis 1 and Master System both have these same jailbars you are referring to, very narrow in width and mostly noticeable on shades of blue. I never noticed them on my RGB monitors but once I switched to OSSC they really stood out. I ended up switching to a Genesis 2 which also had the CXA1145 but exhibits none of these issues. Just worse audio so I ended up doing the sound mod instead. There's a couple of fixes that worked for some people like lifting/grounding a pin on the cxa1145 but didn't work for me. There are some models that have a cxa1645 instead, you might get a clearer picture with one of those. Sega-16 has a detailed guide on models and variants.
 

oliverclaude

General Morden's Aide
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Feb 3, 2013
Posts
7,688
You can get rid of jailbars (they appear on blue areas) via a mod, at least for RGB.
 
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