To mod or not to mod?

[Greg2600]

On 9/21/2020 at 5:48 PM, -^CrossBow^- said:

Not sure which mod you have, but even with the UAV there is some differences in the way the colors look. Tower Toppler is the worst offender as even through composite, the colors on tower toppler are not correct and the invert jumper that can be used for the 5200 and 8-bits will not work when used on a 7800 and I would presume a 2600 either. So that is one strong reason for keeping the RF intact when doing these and thankfully the UAV makes that easy since nothing has to be removed to use it.

 

I think the reason for the slight color variants on some games has more to do with the more pure signal the UAV is able to generate vs what the build in RF was doing. And naturally with s-video you loose artifacting completely and that can be jarring on the games that really used it if you aren't used to seeing them that way.

Mine is an old Longhorn, and the RF is disconnected as you know, so I can't really say if the mod resulted in incorrect colors.  However, I'm not the only one who gets greens instead of blues in 320 (Rikki & Vikki). We went back and forth about it on the UAV thread.  I tried fiddling with the color pots, but it's just not accurate enough for me.

[+-^CrossBow^-]

For sure with composite you do get green pea soup colored water. It only looks the right color in RF and will be blue in s-video but then has the vertical striping on it since the artifacting for the water is then non existent. 

 

Tower Toppler is really the only game I've seen with very wrong colors through composite from the UAV and I've not aware of a fix for that from the UAV. But it is the only game I've seen that much out of whack through composite.

 

[Greg2600]

Well even on Donkey Kong I observe the coloring is off, DK is far too dark vs. the reddish color he should be. 

[+-^CrossBow^-]

3 hours ago, Greg2600 said:

Well even on Donkey Kong I observe the coloring is off, DK is far too dark vs. the reddish color he should be. 

You mean with your LHE mod in place? I've not noticed any color issues with any other games other than Tower Toppler and the water in Rikki & Vikki but again that is only through composite. S-video looks as it should minus those games that rely on artifacting to achieve certain color effects like again, Tower Toppler and Rikki & Vikki. I would still rather use the s-video out to play those games than the RF output which was pretty atrocious on my 7800 before.

 

Ultimately to answer the OPs original question. I mod the consoles that I plan to use as my daily drivers so that I can have the most versatile setup available to use them. Be that RF, composite, s-video or RGB in the case of my classic consoles. Some of my others have HDMI that I added such as my Hi-DEF NES, and DCDigital in my Dreamcast. I wouldn't want to play those systems any other way after seeing how clear and sharp they now appear on my modern displays.

 

[Greg2600]

Yes, the colors are off on most games.  The 2600 colors are much more noticeable, particularly Activision games.  I think it's just this individual console, hence why I want to have S-Video done on a different one.

[+DrVenkman]

19 hours ago, -^CrossBow^- said:

For sure with composite you do get green pea soup colored water. It only looks the right color in RF and will be blue in s-video but then has the vertical striping on it since the artifacting for the water is then non existent.

Looks aqua to me. *shrug*

 

 

[+-^CrossBow^-]

5 minutes ago, DrVenkman said:

Looks aqua to me. *shrug*

 

 

Is that RF or composite? On my 7800 with the UAV I get pea green as a few others have found. I only get that color through RF. I do get that color through s-video but with the vertical stripes. I even posted screen shot comparisons of this either earlier in this thread or another. Then again, all of that testing was through an LCD so perhaps on a CRT the artifacting would work properly. I do see the purple tinting on the left edges of the water that I also see on composite through a UAV.

 

[+DrVenkman]

22 minutes ago, -^CrossBow^- said:

Is that RF or composite? On my 7800 with the UAV I get pea green as a few others have found. I only get that color through RF

Hmm, that’s a good question. I think this is RF - I didn’t put a UAV into my 7800 until a few months after this pic and I can’t find a good pic of Rikki & Vikki since then.  

 

I wonder if @TailChao has any thoughts about what he thinks Rikki & Vikki “should” look like through composite? Or @Trebor, who has done such excellent work documenting the 7800 palette? 

[TailChao]

20 minutes ago, DrVenkman said:

I wonder if @TailChao has any thoughts about what he thinks Rikki & Vikki “should” look like through composite? Or @Trebor, who has done such excellent work documenting the 7800 palette? 

I tried to draw the graphics to look okay with some variation in the palette, since the color generation is wonky anyway. Generally the shots from my Linytron are what I'd expect from composite - but in any case you'd want the colors over RF replicated as closely as possible. Here's some shots from the Rock Cavern to compare, one of which is old enough that it was before we started tweaking the stage layouts after focus testing...

 

 

So the aqua is what I'd want.

 

I was trying to figure out how to reliably duplicate this in a new composite mod design but never got around to it. What I can recall is lots of the existing mods just kinda smash Maria and Stella's chroma together with two resistors and this can lead to color drift - if you digitally combine them there'll be less crosstalk. Also, Tiido pointed out that C2 near Q2 in the NTSC board schematic is kinda questionable, and I agree... it looks like they were going to decouple Q2 and messed up - removing this reduced color variation as well.

Edited September 24, 2020 by TailChao

[+-^CrossBow^-]

Well, I don't recall where I posted it before, but here is a link to a video where I compare the composite and s-video through my 7800 with a UAV. This isn't direct capture and was done with my camcorder aimed at my LCD panel. So it is showing as close to what I was seeing with my own eyes as possible. You can immediately see the pea green/teal colored water through composite on my LCD. I didn't capture RF on this video because the RF modulator has been removed from my main 7800 that was used for this. But I've tested it with other consoles I've worked on and the RF looks like @DrVenkman's screenshot above. The s-video produces a more correct color but with stripes since the water does make use of artifacting to produce the actual color intended.

 

 

[gilsaluki]

On 9/21/2020 at 11:06 AM, GoldenWheels said:

So I have a composite modded and a standard 7800...oddly (compared to community reaction) I always found the RF on my 7800 very GOOD (better than any other RF system I own, including Coleco, Intellivision, and my 2600) and while composite does make some games look a lot nicer....part of me really misses some of the ghosting when playing Joust.

 

There is just something about playing Joust on RF in the dark while that ostrich arcs across the black screen, leaving a phosphorescent trails behind it. Those trails remind me of being a kid...for multiple reasons!

My RF is just fine running on CRT (very later-built SamSung TV).  Very clean.  No need to modify.  

[adamchevy]

My RF is just fine running on CRT (very later-built SamSung TV).  Very clean.  No need to modify.  

My RF on a later Sony Trinitron looks great as well out of my Heavy Sixer. I do notice that the colors aren’t as vibrant compared to my RGB modded Heavy Sixer.

[+-^CrossBow^-]

5 minutes ago, gilsaluki said:

My RF is just fine running on CRT (very later-built SamSung TV).  Very clean.  No need to modify.  

I've seen quite a few 7800s come through my hands that had really good RF as well so yes the RF can look good but it does vary from console to console and TV to TV. The quality of the cables help as well. I use really short 3ft RF Cables that are good quality in my setup for testing and for those few consoles that I haven't added composite or s-video to in my collection that I might use routinely.

 

[gilsaluki]

37 minutes ago, -^CrossBow^- said:

I've seen quite a few 7800s come through my hands that had really good RF as well so yes the RF can look good but it does vary from console to console and TV to TV. The quality of the cables help as well. I use really short 3ft RF Cables that are good quality in my setup for testing and for those few consoles that I haven't added composite or s-video to in my collection that I might use routinely.

 

Agreed.  I have modified a 7800 (composite RCA jacks).  It really didn't improve the video enough to justify the cost, time, and burnt finger tips (always burn myself using a soldering iron).  So, I leave it alone.  Then again, I am not that particular.  Thankfully I still have a good supply of good CRTs for the foreseeable future.  My wife hates them, says they are "ugly".  Whatever. 

[Greg2600]

 

That's my LHE composite with the green. 

 

 

Overall the picture quality from the LHE is fine, but the color balance I just am not fond of.  It's more demonstrable via the naked eye, blues and reds are just simply too dark, on both 7800/2600 games.

[desiv]

For me, I modded my 7800.  Mostly for ease of use/access.

I'm not a "collector" and I'm not super picky if the colors are off a tad, as long as I am still enjoying the game.

I do have a CRT TV downstairs, but I generally use the RF on that for the older systems, and my 7800 is on my 1702 monitor upstairs.

[newtmonkey]

I modded my 7800 for composite as I had no other way to play it due to differences in US and JPN RF channels.  I literally had no other way to play my 7800 other than, I dunno, importing an old US TV or VCR?

[+slx]

I have a 7800 hooked up to a B&O MX4000 CRT via RF and get quite a nice picture. It is not really noticeably worse than the direct SCART connection from the French unit. Both won't show anything at all via RF on a 10-year-old Philips TV (and the newer models don't even support analog RF input). I have a UAV board and will eventually mod the non-SCART unit to be able to connect to modern displays as the CRT is too heavy to lug around.

[adamchevy]

Agreed.  I have modified a 7800 (composite RCA jacks).  It really didn't improve the video enough to justify the cost, time, and burnt finger tips (always burn myself using a soldering iron).  So, I leave it alone.  Then again, I am not that particular.  Thankfully I still have a good supply of good CRTs for the foreseeable future.  My wife hates them, says they are "ugly".  Whatever. 

My wife also hates my Sony CRT. I keep it around because it was one of the last ones made that has component and Svideo. It will do 1080i output. It’s the last one I think I’ll purchase. It weighs 250lbs and is awkward to move for two people.

[Geoff Oltmans]

From what I've seen personally, there's a pretty big difference in RF output quality depending upon the tuner. I have an old TV with the VHF/UHF tuning knobs and I swear even though it's not the best quality set overall (it's a GE Portacolor 9"), the RF output is very clean. By comparison, the late-90's VHS RCA VCR connected to a composite monitor looks pretty noisy with the same cabling, and my modern TV ( < 3  years old) looks absolutely horrid with anything RF or composite.

 

[+slx]

17 hours ago, Geoff Oltmans said:

From what I've seen personally, there's a pretty big difference in RF output quality depending upon the tuner. I have an old TV with the VHF/UHF tuning knobs and I swear even though it's not the best quality set overall (it's a GE Portacolor 9"), the RF output is very clean. By comparison, the late-90's VHS RCA VCR connected to a composite monitor looks pretty noisy with the same cabling, and my modern TV ( < 3  years old) looks absolutely horrid with anything RF or composite.

 

The 7800s were not really built for digital LCD TV tuners (and modern TVs analog tuners are probably built cheaper and with less attention given to them than when analog TV was the main way to get pictures in). My 10 year old philips TV LCD refuses to recognize the 7800s RF output altogether and another unit struggles, the 7800's RF is maybe at the edge of spec. (all PAL experiences)

[RevEng]

On 9/24/2020 at 10:27 AM, -^CrossBow^- said:

[...] You can immediately see the pea green/teal colored water through composite on my LCD. I didn't capture RF on this video because the RF modulator has been removed from my main 7800 that was used for this. But I've tested it with other consoles I've worked on and the RF looks like @DrVenkman's screenshot above. The s-video produces a more correct color but with stripes since the water does make use of artifacting to produce the actual color intended.

"color intended" is always a crapshoot with artifacting colors. The two artifacting colors depend on where the luma edge lines up with regard to the colorburst reference. Any slight delay in the luma signal path will alter the color of the two artifact colors. Green is later than Blue in YIQ color space, so your luma is a bit delayed compared to systems that are showing blue for the water in R&V.

 

A while back Trebor and I did a study of how artifact colors vary with the underlying color. The discovery he made was that the video mod adds another layer of complexity to the situation above. A simple transistor mod will shift the artifact phase with the phase of the underlying color, while a mod that tries to clean up signal edges will leave the artifact colors unshifted.

 

 

Each brick above has the base color on top, and then the two artifact colors generated with it underneath the base color.

 

Artifact colors are useful, but it's impossible to guarantee that any particular artifact color will be displayed the same on different consoles, and really there's no real "correct" set of artifact colors.

[koolmoecraig]

The way I look at it is that my eyes were way better back in the 80's. The UAV mod returns my eyes to their original condition

[Geoff Oltmans]

12 hours ago, slx said:

The 7800s were not really built for digital LCD TV tuners (and modern TVs analog tuners are probably built cheaper and with less attention given to them than when analog TV was the main way to get pictures in). My 10 year old philips TV LCD refuses to recognize the 7800s RF output altogether and another unit struggles, the 7800's RF is maybe at the edge of spec. (all PAL experiences)

Yes, I can imagine noise rejection by the tuner circuit before passing it to an LCD's image processor is very important, since it will likely introduce it's own noise when attempting to figure out how to scale the image and whatnot.

[Trebor]

19 hours ago, RevEng said:

Artifact colors are useful, but it's impossible to guarantee that any particular artifact color will be displayed the same on different consoles, and really there's no real "correct" set of artifact colors.

Indeed.  And while Eutrophication is actually a thing, placing green water in the realm of possibilities, naturally or otherwise, unless the game is borrowing an idea from Ghostbusters II*, it can be considered fortunate some consoles are not experiencing pink water.

 

As we have also witnessed when comparing artifact color console differences, in some instance(s), an end result of cyan, while another was pink:

 

 

*Disclaimer...I am not denying a possible link between Vigo and Misery the Inconvenient.