NES RGB mod

[Drakon]

So, I'm working on my RGB kit for the Famicom AV and I'm getting close! But all I seem to get is pictures like these:

http://imgur.com/hqxwt.jpg
http://imgur.com/hkDzg.jpg
http://imgur.com/UK3CT.jpg

It appears to be pulling sprite information from the wrong addresses, or something like that. It should be noted that I can't get the one actual Famicom game I have to load up. The only games that I can get to load are NES games thru a NES-to-Famicom converter. Sound comes through just fine. It's just the pictures are garbled. At least the colors are crisp and bold thanks to the RGB! But, yeah, this is something of an issue.

And I'm pretty sure it's not the fault of the converter, since I got NES games to play on the system with it just fine before I started the modding. The PPU I'm using is RP2C03B, which I think is compatible but I'm not 100% sure since my Japanese is rusty. (For reference: http://homepage3.nifty.com/F-LABO/ProductsList.html ; third item down.)

Any advice?

yikes, only time I had stuff like that happen was when some pins weren't connected, check your connections.  I really gotta find a way to make a low pass filter to get rid of these stupid lines...

[RGB32E]

Did you order this kit?



I'd really like to get just the PCBs for this kit!!!  I suppose I could just design my own.... hmmm...    

So, I'm working on my RGB kit for the Famicom AV and I'm getting close! But all I seem to get is pictures like these:

http://imgur.com/hqxwt.jpg
http://imgur.com/hkDzg.jpg
http://imgur.com/UK3CT.jpg

It appears to be pulling sprite information from the wrong addresses, or something like that. It should be noted that I can't get the one actual Famicom game I have to load up. The only games that I can get to load are NES games thru a NES-to-Famicom converter. Sound comes through just fine. It's just the pictures are garbled. At least the colors are crisp and bold thanks to the RGB! But, yeah, this is something of an issue.

And I'm pretty sure it's not the fault of the converter, since I got NES games to play on the system with it just fine before I started the modding. The PPU I'm using is RP2C03B, which I think is compatible but I'm not 100% sure since my Japanese is rusty. (For reference: http://homepage3.nifty.com/F-LABO/ProductsList.html ; third item down.)

Any advice?

[xenomus]

Yes, that is the kit I got. I told of a way to order it through a shipping proxy on the previous page, if you are interested.

A minor update on my situation: I swapped the kit out for the original PPU and got the same graphical glitches which confirms that it's probably just some bad contacts between the socket and the board and not a problem on the RGB kit side. So next, I shall try cleaning and resoldering the contacts to the best of my ability.

[capcom2010]

I finally got around to give this new NES RGB mod a try. Video and color saturation wise is excellent, but It seems that I'm not the only one having the horrible "Jair bars" issue   . Which is basically killing the purpose of having RGB   ...Here are a few pics showing my NES with the new RGB mod (gameplay taken directly from a crt tv screen, and using a RGB to component converter):

Super Mario Bros 3



Metroid


The camera didn't get the best video quality details on these shots, but you can clearly see the bars effect...
Also, I noticed that those bars get even worse if the recommended 68pf ceramic cap is installed in pin 24 (RD/OE) of the RP2CO3B (which seems to be necessary either way).So the problem is around that area....

Quick question, do the previous NES RGB amps also show the problem?...

[Xenogias]

Yes, that is the kit I got. I told of a way to order it through a shipping proxy on the previous page, if you are interested.

A minor update on my situation: I swapped the kit out for the original PPU and got the same graphical glitches which confirms that it's probably just some bad contacts between the socket and the board and not a problem on the RGB kit side. So next, I shall try cleaning and resoldering the contacts to the best of my ability.

On a brighter note,  I can't see any jail bars!  I'm eagerly waiting to see your final results for this =]  By the way,  which of the kits did you get, the multi av or RGB-only.  It looks like they have 3 versions of each with different prices...is this for pre-assembled vs un-assembled or something else?

[Drakon]

I'm having quite a jailbar problem here too.  I'm also looking for a solution

[RGB32E]

Which amp design are you using?  The NES seems to be very sensitive to noise, and many caps might have gone bad, so there could be a number of contributing factors.  Here's what mine looks like (via XRGB-3):

I finally got around to give this new NES RGB mod a try. Video and color saturation wise is excellent, but It seems that I'm not the only one having the horrible "Jair bars" issue   . Which is basically killing the purpose of having RGB   ...Here are a few pics showing my NES with the new RGB mod (gameplay taken directly from a crt tv screen, and using a RGB to component converter):

Metroid

[capcom2010]

Which amp design are you using?  The NES seems to be very sensitive to noise, and many caps might have gone bad, so there could be a number of contributing factors....

The latest RGB amplifier ( using the pair of NJM2267's)...

Is that photo of yours taken out of a NES or Av Famicom system?....

...

[Drakon]

The latest RGB amplifier ( using the pair of NJM2267's)...

Is that photo of yours taken out of a NES or Av Famicom system?....

...

well that saves me a bit of work.  I didn't make a njm based amp and I wasn't sure if it was my amp that was the problem.  From what I found on the internet it seems certain models of the nes have this issue.  So it LOOKS like the problem isn't the ppu or the amp but something to do with the system (bleh)

Quick question, do the previous NES RGB amps also show the problem?...

Yes it does.  I've built 2 different types of amps and both had the lines.  Heck even when I hookup my system without any amp I still get the lines.

I've tried this one that I made out of a modded mooseman amp



And I've also tried the simple pce amp

http://www.gamesx.com/grafx/pce_rgb.jpg

both have jailbars

And what do you mean that the 68pf cap is necessary?  I don't have it installed at my graphics are fine except for the jailbars.  I wonder if using a resistor on the rd/oe line would do anything?

[capcom2010]

So it LOOKS like the problem isn't the ppu or the amp but something to do with the system (bleh)

Seems to be a PPU digital inteference..

And what do you mean that the 68pf cap is necessary?  I don't have it installed at my graphics are fine except for the jailbars.  I wonder if using a resistor on the rd/oe line would do anything?

Well,  most games work just fine with the RGB PPU , but others excibit some graphic problems (glitches or scrambled screen)....I can't recall who suggested adding a 68pf -and up ceramic cap to the RD / OE line , pin 24 to fix these problems....And it definitely works, I was having troubles with Megaman 2, added the cap, and the game worked perfectly afterwards....

[Drakon]

Well,  most games work just fine with the RGB PPU , but others excibit some graphic problems (glitches or scrambled screen)....I can't recall who suggested adding a 68pf -and up ceramic cap to the RD / OE line , pin 24 to fix these problems....And it definitely works, I was having troubles with Megaman 2, added the cap, and the game worked perfectly afterwards....

it was mooseman who came up with the 68 pf cap idea

http://playoffline.wordpress.com/mod/nesrgb/

My megaman 2 plays flawlessly except for the bubbleman stage which has some very minor graphic randomness.  But it's so small that it's not even worth bothering with installing the cap.  Right now my concern is just removing those stupid jailbars.  I find it strange that adding the 68pf cap made the jailbars worse.  Right now I'm grounding my video just to a random ground on the nes pcb instead of a ground wire on the ppu slot.   Would that possibly be a part of the problem?  Also my amp has power coming from a seperate psu.  And I amp sync with an amp I built instead of using the nes video amp.

also step 5 of this site

http://jpx72.detailne.sk/modd_files/fc/avmod.htm

suggests that adding a cap on two ppu pins reduces the vertical bars when using a composite signal.  Would doing this also help a rgb signal?

here's another POSSIBLE solution

http://www.famicomworld.com/forum/index.php?topic=3057.msg42243#msg42243

again it's based on a composite signal and not rgb

[Drakon]

I FIXED THE VERTICAL BARS/LINES/JAILBARS.  Very exciting.  All thanks to a brilliant idea from rt9342.  The reason you get crazy lines is because moosman said you're supposed to keep pin 17 of the ppu attached to the nes pcb.  This is INCORRECT (atleast for me).  You should disconnect pin 17 from the nes pcb and wire it straight into your rgb connector as video ground.  If you connect pin 17 of the ppu to the ground of the nes pcb that's what causes the noise making the massive vertical lines on the picture.  When you keep pin 17 it on a seperate ground from the nes pcb the lines are still there but BARELY noticable and definitely not enough to make the picture look bad.  rt9342, hats off to you sir.

Basically this rgb ppu (rp2c03b) has 2 ground pins.  Pins 17 and pin 20.  Pin 20 seems to be just a regular ground like the ground you get from a regular nes ppu.  However pin 17 is NOT a regular common ground pin.  According to rt9342 pins 17 and 20 are NOT connected inside the ppu.  The reason is that pin 17 is a video ground ONLY.  In fact it's ultra sensitive to everything so it should be ONLY hooked into video signal connections.  On the regular nes ppu pin 17 doesn't do anything that's why the pcb has this pin connected to common ground.

Also major thanks to RGB32E.  He also had some great ideas that wound up not really fixing the problem but still he was totally willing to help me in any way he could.  Very great member on this forum

Okay this PPU is EXTREMELY sensitive.  I hooked up the positive audio wire and got sound and the picture was still perfect but there was a slight buzz noise because the audio wasn't grounded.  As soon as I hooked up the audio ground wire the picture goes a little off.  The lines come back a tiny bit and other small things happen.  In mario 3 if you scroll the screen during a stage faint diagonal lines appear.  If the audio ground is left disconnected the picture is perfect and the diagonal lines go away.  But you have to deal with a slight buzzing sound....man this is weird.

[capcom2010]

Which RGB amp did you used in the end?..  

[Moosmann]

I tried this, but it doesn`t work. The lines are still visible in Castlevania 2 and other "problem" titles.
I also tried lift Pin 17 without ground, but don`t make a difference.

Greetings Markus

[Drakon]

I tried this, but it doesn`t work. The lines are still visible in Castlevania 2 and other "problem" titles.
I also tried lift Pin 17 without ground, but don`t make a difference.

Greetings Markus

maybe your nes is a different model.  Or maybe your setup is different.  I'm using a rgb to s-video converter and when I had pin 17 connected to the nes pcb I was having the exact same type of picture as capcom2010.  As soon as I removed pin 17 from the pcb and wired it into video ground the image completely cleaned up.  I don't have a castlevania 2 but my mario 2 was by far the worst game I had in terms of video image full of lines.  Switching between using pin 17 and the common ground for my video signal is really like night and day for that game and any other game.  Using pin 17 doesn't 100% get rid of the lines but on my rig it gets rid of about 95% of them.

And capcom2010 for some reason amping the rgb on my rig works but doesn't look quite right.  Since I'm using s-video I just wound up using the amp I made on the brightness of the s-video signal.  Strangely the unamped signal that comes from the ppu is dark but has super strong colour saturation.  So I actually didn't need to amp the colour at all just the brightness to make the picture perfect

Moosmann I read from other posts that different versions of the nes apparently have worse lines than others.  And disconnecting pin 17 from the nes pcb and wiring it into video ground doesn't make anything worse.  So there's really no harm in doing what I did.  Maybe for your system it doesn't make a difference but for me it makes a MASSIVE difference.  I hope other people who have lines as bad as capcom2010 try what I did to see how well this really works.

(by the way moosmann your amp rocks it's much stronger than the pce one I built)

Okay I did some more testing and wiring the pin 17 ground into the ground for my video amp does not damage to the picture.  Not a big issues but someone pmed me asking about this so that's now the 3rd person who's come forward with this exact same issue.

[Arasoi]

Drakon, thanks for answering my questions. I just finished giving the mod a try.

Unfortunately, at least on my NES deck lifting pin 17 and grounding it (or leaving ti ungrounded) made no difference in signal quality for me. The jailbars in Megaman 2 stayed the same as normal.

Perhaps this mod hinges on differences between NES motherboard revisions.

[Drakon]

Drakon, thanks for answering my questions. I just finished giving the mod a try.

Unfortunately, at least on my NES deck lifting pin 17 and grounding it (or leaving ti ungrounded) made no difference in signal quality for me. The jailbars in Megaman 2 stayed the same as normal.

Perhaps this mod hinges on differences between NES motherboard revisions.

really?  That's really weird.  What's it grounded to?  Make sure that whatever it's grounded to doesn't connect to the common ground of the nes (any ground connection that's not pin 17 from the ppu and make sure that pin 17 is DISCONNECTED from the nes pcb and not connected to the nes in any way.)

Maybe this also has to do with the type of rgb ppu you're using?  I'm using a rp2c03b (atleast that's what it says on the chip).  That's very odd because on my system it makes a massive difference on the picture quality.  There's nothing I want more than to find a way to fix this problem for everyone.  I wonder if it only shows up on a signal that's converted to s-video etc.  Capcom2010 those line-tastic screenshots you took is that on a tv accepting the rgb signal or has it been converted into something else like s-video?

[Arasoi]

I can confirm I connected to a completely separate ground, it was not in any way associated/attached to the NES motherboard. No difference. I have RGB and svideo (through the JROK encoder in my NES) going to two monitors I am looking at, it made no difference in either.

The PPU I have is also a RP2C03B.

[Drakon]

I can confirm I connected to a completely separate ground, it was not in any way associated/attached to the NES motherboard. No difference. I have RGB and svideo (through the JROK encoder in my NES) going to two monitors I am looking at, it made no difference in either.

The PPU I have is also a RP2C03B.

I'm also using a rp2c03b
oh poo that's terrible.  As you can see from my screenshots my picture's pretty darn perfect.  Anyway my nes pcb says copyright 1987.  Any other ways I can verify what revision of the nes pcb I'm using?  I was really hoping this would be a universal fix and not something that would make people have to buy a certain model of the nes.....

wait.....you get a picture if pin 17 is connected to nothing??

[Arasoi]

I do. I used Moosman's diagram on his site to make sure I was lifting the right pin. From his last post in here it seems he did also, though he would need to confirm.

[Drakon]

I do. I used Moosman's diagram on his site to make sure I was lifting the right pin. From his last post in here it seems he did also, though he would need to confirm.

I've never tried connecting pin 17 to nothing and seeing if I still get a picture.  However here's the e-mail I got from rt9342

"I learned about the PPU's separate grounds by accident.  When I first put a PPU socket in my NES, I left pins 14-17 disconnected, for the RGB outputs, and I figured, well, the PPU is already grounded by pin 20, so no need to ground pin 17.  And there was no picture..... until I grounded pin 17, and all of a sudden, picture!  Later, I pulled out the PPU and connected an ohm-meter across pins 17 and 20, and they were definitely not connected.  That's how I found out - I'd doubt that any info on that exists on the internet - maybe you and I can help change that."

As you can see he didn't get any picture with pin 17 connected to nothing.  So it's kinda strange that you do......

My playchoice board that the ppu came from says copyright 1986 and it's got a rp2a03e cpu.  It's a dual moniter board.  Don't know if there's something about that year/revision/type of pcb that gives me a different ppu...

took a pic of my tv it's much brighter than that it's just my camera being strange but you can still see the clearness

[Arasoi]

Turn off the lights and photo the screen with no flash.



Anyway, I'm not sure why pin 17 doesnt need to be grounded on my NES and does on rt9342's. I double checked that I had the right pin, and tried everything again, and got the same result. Go figure.

[Drakon]

I turned off the lights and took a pic with no flash.  Probably need to adjust something on my camera 

[Arasoi]

Snapped this from my Holo3dgraph's RGBs input. The JBs are fairly negligible, at least compared to some other shots I've seen of folks trying to reduce them.

[Drakon]

Snapped this from my Holo3dgraph's RGBs input. The JBs are fairly negligible, at least compared to some other shots I've seen of folks trying to reduce them.

that doesn't look half bad at all.  Have any games that really make them go bad?

[Arasoi]

Oddly enough, not really. Megaman 2 is one of the games where JBs are more prevalent, along with Castlevania 2 so thats about as evident as they get. Games like Metroid seem to have none at all. Some of the interference there in the screencaps is due to the cheap Genesis 1 SCART cable I'm using, which puts a bit of a crosshatch pattern onto the image. I need to build a better one but haven't quite gotten around to it.

The JBs show up much more via the holo3dgraph, as opposed to my Sony PVM monitors where a few tweaks of the controls can erase them almost completely.

[Drakon]

Oddly enough, not really. Megaman 2 is one of the games where JBs are more prevalent, along with Castlevania 2 so thats about as evident as they get. Games like Metroid seem to have none at all. Some of the interference there in the screencaps is due to the cheap Genesis 1 SCART cable I'm using, which puts a bit of a crosshatch pattern onto the image. I need to build a better one but haven't quite gotten around to it.

The JBs show up much more via the holo3dgraph, as opposed to my Sony PVM monitors where a few tweaks of the controls can erase them almost completely.

okay that's really interesting.  When I still had the bars megaman 2 was one of the games that didn't have it badly except for some bosses with all black backgrounds.  But in comparison to other games like mario 2 and even tmnt the arcade game megaman 2 was much much better.  I get the exact same cross hatch pattern on my image.

*edit* here's some screens

My capture card picks up some very very minor lines which don't show up on my tv

[FA-MAS]

Can the PPU swap be done on a NES toploader?

[Xenogias]

Drakon are you saying your wired pin 17 directly to the Scart socket ground?  Or are you grounding it to a location on the NES PCB?  The humming you get comes from the ground sharing of audio and video in a scart socket.  I think there is a way to eliminate the humming if you can separate the ground pins in the socket from the ground pins for audio and run a separate ground wire for the length of the cable...need to research it more.

[DarkCecil]

Hi, new to this thread, and I'm going to attempt this mod pretty soon. Anyways, I was reading about pin 17 being connected on a separate ground. So, I grabbed my PC10 board and took the ohm-meter to pins 17 and 20 on the DIP socket... and found that they are connected together on the board... So, great, another wrench in the jailbar puzzle?

[Drakon]

Can the PPU swap be done on a NES toploader?

yes, it can be done on any model of the nes and famicom

Drakon are you saying your wired pin 17 directly to the Scart socket ground?  Or are you grounding it to a location on the NES PCB?  The humming you get comes from the ground sharing of audio and video in a scart socket.  I think there is a way to eliminate the humming if you can separate the ground pins in the socket from the ground pins for audio and run a separate ground wire for the length of the cable...need to research it more.

wired pin 17 straight into the scart socket and don't connect it to the nes pcb at all.  First thing I tried was seperating the audio ground but it didn't work.  The humming is caused by the fact that my audio isn't grounded at all.

If anyone bothers attempting my jailbar fix please remember not to ground the audio.  In fact the only things my system has grounded is pin 17 of the ppu is grounded to my scart cord and obviously the ground of the ac adapter for the system.  You have to make sure that no other grounds on the system are connected to anything external otherwise my jailbar fix doesn't work.  As soon as I wire up the ground of the audio to anything the picture looks terrible but if I leave it disconnect things're rocking.  Also keep in mind I amp my sync signal outside of the console and not through the internal amp as moosmann's guide suggests.  Whatever causes the jailbars I'm guessing that it has something to do with the power in the machine.  I've found some interesting threads on theories of what causes the vertical lines and how to fix them.  The best one I found is on famicomworld but I can't access it right now for some reason (will post when it works again).  Basically it's a thread where someone claims that a big capacitor that has something to do with converting the ac to dc is dried out and doesn't do a smooth job converting the electricity causing slight fluxuations in what's supposed to be smooth dc power.  There's many guides out there like this one:

http://jpx72.detailne.sk/modd_files/fc/avmod.htm

telling you to wire a cap between the 5v and ground lines of the ppu.  I'm guessing that this fix smoothes out the fluxuating power that's supposed to be smoothed out by a capacitor elsewhere on the system but has supposedly dried up and stopped working right because it's umpteen years old.  I'm way too chicken to try these fixes right now especially considering that I've got things pretty much perfect by basically bypassing as much of the fluxuating ground connections of the system as possible.

another odd thing that happens is if I amp the rgb lines then the image has a white border on the right side of the graphics.  It doesn't matter which amp I use they all give me the white border.  I'm guessing this's caused by the same image distortion that creates the jailbars.  I didn't fart around much with trying to fix this issue since I'm using s-video and amping the s-video brightness requires just one amp instead of 3.  And amping the brightness of the image after it's been converted to s-video doesn't give me that weird white border on the right side.

This does concern me a bit and possibly my jailbar fix might only work on an image that's been converted to s-video and amped after it's converted.  I don't have a rgb tv to test this fix on so keep that in mind when trying my work-around.  If the problem is the power of the system (which RGB32E suspected all along) then my fix doesn't really eliminate the issue it just sort of works around it.  Probably a better solution for this would be finding a way to measure the dc power going through the system and seeing exactly how smooth it's flowing.  And if the power is a fluxuating dc instead of a proper one then as RGB32E suggested giving the system a new source of power might be the TRUE fix to this nasty problem.

[Arasoi]

I'd be interested to know which capacitors on the board are the ones that supposedly fail and create the noise that makes the JBs. It's not really hard to replace a cap or two and I'd be willing to give the fixes a try and post results.

[Drakon]

I'd be interested to know which capacitors on the board are the ones that supposedly fail and create the noise that makes the JBs. It's not really hard to replace a cap or two and I'd be willing to give the fixes a try and post results.

here's the thread discussing it

http://www.famicomworld.com/forum/index.php?topic=3057.msg42243#msg42243

the nes has this cap too but it's inside of the system instead of the ac adapter.  I'm guessing it's the big one sticking outside of the ac part of the system.  But I can't say for sure.  Good luck.  I tried pming this guy asking him if it will work on a rgb system but his response was that something's wrong with my rgb setup even though lots of people have the same problem as me....  So I very much think this is worth trying

[Arasoi]

Well it's definitely not the power adapter, I plugged in a Genesis 1 AC adapter and the JBs remained.

The Genesis 1 adapter is DC though, would this bypass the AC/DC conversion cap inside? Or should I still try replacing the cap?



I believe the two points to desolder are these:

[Drakon]

Well it's definitely not the power adapter, I plugged in a Genesis 1 AC adapter and the JBs remained.

The Genesis 1 adapter is DC though, would this bypass the AC/DC conversion cap inside? Or should I still try replacing the cap?



I believe the two points to desolder are these:

yes that's the cap try giving that one a swap.  I mentioned before the cap should be inside the system and not the ac adapter.  I dunno if a genesis adapter would bypass it.  The above thread from famicomworld mentioning this fix is meant for a composite video signal but I figure it's worth a try.

I'm no expert on this but I'm guessing that this fix here:
http://jpx72.detailne.sk/modd_files/fc/avmod.htm
at step 5 is the same concept?  Using a cap to smooth the electricity going into the ppu?

[Arasoi]

I am willing to try both and ordered the components as such. I am a bit worried about the pin 20/40 mod as I already have the 68pf cap mod installed, which also goes to pin 20. It probably be allright (ground is ground) I suppose.

[Drakon]

I am willing to try both and ordered the components as such. I am a bit worried about the pin 20/40 mod as I already have the 68pf cap mod installed, which also goes to pin 20. It probably be allright (ground is ground) I suppose.

yeah obviously replacing the cap is the safer mod so try that one first.  And yes ground is ground your system has many things tied into that very same ground.  If you're worried you could disconnect the 68pf cap first it won't stop the system from running

[Hamburglar]

That was one of the first things I tried when modifying my 1st version NES for RGB, replacing that cap, didn't do anything, lines were still there.

Well it's definitely not the power adapter, I plugged in a Genesis 1 AC adapter and the JBs remained.

The Genesis 1 adapter is DC though, would this bypass the AC/DC conversion cap inside? Or should I still try replacing the cap?



I believe the two points to desolder are these:

[Drakon]

That was one of the first things I tried when modifying my 1st version NES for RGB, replacing that cap, didn't do anything, lines were still there.

doh so I guess my fix is the only thing that works so far.  Unless someone can find the trace(s) that're causing the interference and show us where to cut/rewire them.

[Hamburglar]

That was one of the first things I tried when modifying my 1st version NES for RGB, replacing that cap, didn't do anything, lines were still there.

doh so I guess my fix is the only thing that works so far.  Unless someone can find the trace(s) that're causing the interference and show us where to cut/rewire them.

The funny thing is the nicest picture I got from a RGB NES was from a NES top loader, even my AV Famicom has slight vertical bars.
One thing I never got around to trying was getting rid of that RF converter/regulator box and redoing the voltage regulator section.