PC Engine RGB jailbars, let us find a working solution

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kamiboy
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PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

Only solution I've found online is this:

http://pcengine.freeforums.org/jailbar-fix-t233.html

Just tried it on my Core Grafx, but no dice. I should mention that I used electrolytic caps rather than the tantalum or creamic that the OP mentioned, but I doubt that is the issue here.

Any modders here have any input into this issue? What is that mod even supposed to be good for anyhow?
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Fudoh
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Re: PC Engine RGB jailbars, let us find a working solution

Post by Fudoh »

Just tried it on my Core Grafx, but no dice
is that a CG1 (dark grey with blue lettering) ? I don't have that one right now, but my CGII barely shows any jail bars compared to my white PCE (both running through the same interface unit with the same RGB mod), so the hardware in use certainly plays a major role.
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Artemio
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Re: PC Engine RGB jailbars, let us find a working solution

Post by Artemio »

I have some information in the issue that I'd liek to share, but I have no solution for a PC Engine.

I have tried the transistor, NJM and THS mods with composite video as sync and pure sync, and in a Duo they are always present in my setup. I am using a PVM2530 and a PVM1944Q, and also an xrgb mini.

However, I modded my TG-16 with the NJM and the jailbars aren't there in the exact same setup, it is using composite video as sync.
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

Fudoh wrote:
Just tried it on my Core Grafx, but no dice
is that a CG1 (dark grey with blue lettering) ? I don't have that one right now, but my CGII barely shows any jail bars compared to my white PCE (both running through the same interface unit with the same RGB mod), so the hardware in use certainly plays a major role.
Indeed, a CG1. I also have a PC Engine Duo that I'll have to try the same jailbar stricken game on in order to compare. Thing is just this weekend I saw the RGB modded white PC Engine of a fellow that had crystal clear video, no artefacts at all.

So far as he can remember he never did do any mods to diminish jailbars, he only mentioned that once he switched the RGB amp to a IC based one over the older transistor based solution the jailbars on his games went away.

Thing is my RGB amp is already a transistor based one.
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CkRtech
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Re: PC Engine RGB jailbars, let us find a working solution

Post by CkRtech »

The link says to put pins 41 and 43 to ground. Pin 41 appears to be power. Pin 43, I am not sure. http://gamesx.com/wiki/doku.php?id=hu6260_netlist
Console5 has it listed as SYN- http://console5.com/wiki/Hu6260

So I guess there is some noise in there that those caps are attempting to filter out.

Otaku's guide also recommends caps - although further down the line - if you want to attempt to "soften" the jailbars. http://www.otakus-store.net/en/content/6-guide-nec-rgb.

So there could be noise in the power. There could be noise from somewhere else. Seems like noise in the power to the chip would lead to various forms of "noise" in any of the signals from that chip.

Does anyone know if the jailbars are present on all colors? According to the "netlist" on gamesx, it looks like there are +5 lines right next to the Red and Blue pins. That could potentially not be good if there is noise present.

Based on what Artemio said regarding the mod on the TG16, I wonder what the +5v on a scope (probed close to a hu6260 +5 pin, for instance) would look like on a TG16 vs a Turbo Duo?
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

Trouble with the otaku solution is that it does not mention the ratings on those caps. I can see from the pictures the four small ones are all likely rated 100uf, but no idea about the big one.
Last edited by kamiboy on Wed Oct 08, 2014 8:43 am, edited 1 time in total.
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keropi
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Re: PC Engine RGB jailbars, let us find a working solution

Post by keropi »

just adding to the caps thing, I have tried them (tantalum) on my white pce with the transistor amp, it did nothing to remove that greyish ghosting on solid blue backgrounds... I use c-sync btw
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Artemio
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Re: PC Engine RGB jailbars, let us find a working solution

Post by Artemio »

I just tested out the otaku solution. I tried out 100uF, 330uF and 1000uF in parallel with C909.

I believe it softens them, the only way to be 100% sure would be to wire a switch so I could toggle between it installed and not, but I had none at hand. I am inclined to say it does make them less visible, but it could be pure placebo since it took me about a minute or two to solder and desolder and test in a dark room. They are of course still noticeable.

I always notice them when running soldier blade, during the intro when close ups are shown surrounded by solid color. And in Magical chase, when the checkerboard before the stage scrolls.

It must be noted that I am currently using the THS mod, with composite video as sync since when I used the sync from the chip amplified by the old transistor mod it didn't get rid of the jailbars, I removed that. I am also using a separate 7805 as power regulator for the mod, since taking the 5volts from other points close to the audio circuit invariable gave me a lot of noise in the headphone port.

In a related note, I have some information for those worried about the capacitors in the Duo being to close to the power regulators. I've read some install a fan in order to reduce the temperature and not reduce the life of teh audio capacitors. I did some measurements with and without a 2" fan installed.


Without fan:
Image
With fan:
Image


Jailbares were unaffected by the fan.
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

I have a single switch that I can use but there are 5 caps involved in the otaku solution so I am not going to bother as I assume a single cap wont make that much of a difference.

I'll try the 4 100uf caps and then a 470uf cap for the big one to see whether that helps.
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

Tried 220uf on C131-135 and 470uf on C103. C103 did nothing I think. C131-135 helped soften the jailbars, once again, I think, could have just been my eyes playing tricks on me.

In any regard none of the mods managed to get completely rid of them. Because the 220uf caps have to go on the bottom of the motherboard I had to take them off as otherwise it would not fit back in the case. If you want to do this mod on your Core Grafx get hold of some flat creamic caps or tants. Cylinder types are too thick.
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

So, I talked to my mate with the crystal clear OG PC Engine RGB mod. The curious thing is that he boosts his csync signal using the amp in the diagram below. I feed my displays the raw sync signal tapped somewhere on the motherboard.

I was going to try the amp myself but I am missing two resistors in my collection of parts. Anyone with the right parts care to give it a go?

Image
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Artemio
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Re: PC Engine RGB jailbars, let us find a working solution

Post by Artemio »

I've tested that as stated above, and it gives the same result in my Duo and setup.
leonk
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Re: PC Engine RGB jailbars, let us find a working solution

Post by leonk »

I'm confused by this thread and was wondering if someone can provide some background information. I recently acquired a TG16 and want to RGB mod it. I was thinking of getting one of these amplifiers:

http://www.neo-geo.com/forums/showthrea ... amplifiers

It's based on the design from this forum: http://nfggames.com/forum2/index.php?topic=4822.0

If I do this modification to my TG16, will I get jailbars in the RGB output? Or is this happening in this case because the AMP design is completely different?
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

Artemio wrote:I've tested that as stated above, and it gives the same result in my Duo and setup.

Ah, so you did, sorry. Well, the bars are not that offensive to look at. They make solid colours look dirty if anything and I can live with that.

One day down the line I might get a few flat 100uf caps and do a permanent otaku mod just for the heck of it.
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

leonk wrote:I'm confused by this thread and was wondering if someone can provide some background information. I recently acquired a TG16 and want to RGB mod it. I was thinking of getting one of these amplifiers:

http://www.neo-geo.com/forums/showthrea ... amplifiers

It's based on the design from this forum: http://nfggames.com/forum2/index.php?topic=4822.0

If I do this modification to my TG16, will I get jailbars in the RGB output? Or is this happening in this case because the AMP design is completely different?
Jailbars seem to happen regardless of which amp you use. It is an issue with the console.
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Artemio
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Re: PC Engine RGB jailbars, let us find a working solution

Post by Artemio »

leonk wrote:If I do this modification to my TG16, will I get jailbars in the RGB output? Or is this happening in this case because the AMP design is completely different?
I don't have jailbars on my TG-16, I modded it with the NJM amp. However, I've had my duo with this mod, the same NJM mod as in my TG-16 and also the transistor based one just posted above; and jailbars are present in the Duo.

I believe you won't have any jailbars on your tg-16 with this mod, since so far it seems they only show up in certain models. We don't have hard evidence yet though.
leonk
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Re: PC Engine RGB jailbars, let us find a working solution

Post by leonk »

Artemio wrote:
leonk wrote:If I do this modification to my TG16, will I get jailbars in the RGB output? Or is this happening in this case because the AMP design is completely different?
I don't have jailbars on my TG-16, I modded it with the NJM amp. However, I've had my duo with this mod, the same NJM mod as in my TG-16 and also the transistor based one just posted above; and jailbars are present in the Duo.

I believe you won't have any jailbars on your tg-16 with this mod, since so far it seems they only show up in certain models. We don't have hard evidence yet though.
That's good to hear. Do you have a link to the "NJM amp" schematics for TG16? I'd like to build one too..
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CkRtech
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Re: PC Engine RGB jailbars, let us find a working solution

Post by CkRtech »

Can any of you guys that are experiencing jailbars isolate your colors and verify that jailbars exist across all three color signals - R, G, and B?
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

That is hard to do though. We would need games with screens made mostly up of solid colours more or less purely painted with each colour component.
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Artemio
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Re: PC Engine RGB jailbars, let us find a working solution

Post by Artemio »

I am just starting work on a version of the 240p suite for the PC Engine, so I will do that solid color test and publish just that here... hopefully soon.
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CkRtech
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Re: PC Engine RGB jailbars, let us find a working solution

Post by CkRtech »

kamiboy wrote:That is hard to do though. We would need games with screens made mostly up of solid colours more or less purely painted with each colour component.
It doesn't have to be a pure, solid color in order to test. Each individual color is going to show everywhere on the screen except for pure color areas (i.e. no red showing on 100% pure blue), blacks, and areas where the current color being tested isn't mixed.

A generally "bright" game would probably be a good to use for testing.
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

What I meant was that you need a large surface area of one colour in order to see the bars well. They are not too prominent and you detect them best when the screen scrolls.

In any regard the test suit is the perfect way to test.

Personally I have a feeling that the bars are on all colours.
alamone
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Re: PC Engine RGB jailbars, let us find a working solution

Post by alamone »

So, is it only the original white PCE / TG16 that does not have jailbars?
Before I sold it, I RGB-modded a Duo-R using the TI 3-channel amp and it had jailbars but I just chalked it up to how the system is.
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

I have a Core Grafx and PC Engine Duo that both show the problem. Beyond that who knows.

Maybe the original PC Engine with a 3 channel amp is the only way to get jailbar free RGB out of a PC Engine.

I think the TG16 uses the same board design as the original PC Engine since it also only came equipped with an RF output, which is why it also does not have the artefact.
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keropi
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Re: PC Engine RGB jailbars, let us find a working solution

Post by keropi »

@kamiboy

I am using the transistor amp you posted on 2 white PCEs - sync amp included - it works fine for me in all my displays and the framemeister , ofc with the dirty look on solid colors... it's not that annoying like a megadrive+lcd , you have to pay attention to find them :lol:
Last edited by keropi on Wed Oct 08, 2014 7:31 pm, edited 1 time in total.
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ApolloBoy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by ApolloBoy »

I eliminated the jailbars on my Duo-R by adding a few caps on the underside of the board. I don't remember exactly where the caps are supposed to be soldered to, but I believe the Otaku's Store site has that info.
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Fudoh
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Re: PC Engine RGB jailbars, let us find a working solution

Post by Fudoh »

Maybe the original PC Engine with a 3 channel amp is the only way to get jailbar free RGB out of a PC Engine.
my CGII barely shows any jail bars compared to my white PCE (both running through the same interface unit with the same RGB mod)
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Artemio
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Re: PC Engine RGB jailbars, let us find a working solution

Post by Artemio »

Here is a small pce rom I just made with solid white and RGB, and scrolling horizontal bars of the three colors over a while and a black background.

https://www.dropbox.com/sh/pb6r81lbrssd ... 1nj9a?dl=0

Press I to switch modes.
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

keropi wrote:@kamiboy

I am using the transistor amp you posted on 2 white PCEs - sync amp included - it works fine for me in all my displays and the framemeister , ofc with the dirty look on solid colors... it's not that annoying like a megadrive+lcd , you have to pay attention to find them :lol:
It is worth noting that my mate originally used the transistor amp for the colours but got jailbars. Then he switched to the 3 channel amp for the colours and got the crystal clear image he has now.
He only uses the transistor for boosting csync.
Last edited by kamiboy on Wed Oct 08, 2014 8:54 pm, edited 1 time in total.
kamiboy
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Re: PC Engine RGB jailbars, let us find a working solution

Post by kamiboy »

Fudoh wrote:
Maybe the original PC Engine with a 3 channel amp is the only way to get jailbar free RGB out of a PC Engine.
my CGII barely shows any jail bars compared to my white PCE (both running through the same interface unit with the same RGB mod)
What RGB mod are you using? Three channel or transistor?
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