Nintendo 64 RGB Blur fixing

[zeruel85]

In making a third and final revision of my PCB, would this be an adequate isolation of return paths for the two major components of the system?

I'm not talking about the layout, but the use of separate grounds and the 10 ohm resistor linking between the two. Digital electronics is my thing, not analog, so if anyone has a better suggestion, please let me know.

Just by the by: I don't plan on selling my board, I plan on leaving it open and making it easy for anyone to build and program their own, so any contributions are more of a community effort and less "making my private project better". I can set up an order link through Macrofab so you can have a fully assembled and tested board arrive at your door for around $60.

(Drawn using TurdCad)

Isn't a ferrite bead more appropriate instead of using a resistor?

[Unseen]

I'm not talking about the layout, but the use of separate grounds and the 10 ohm resistor linking between the two. Digital electronics is my thing, not analog, so if anyone has a better suggestion, please let me know.

As far as I know, anything except a low-impedance ground connection is a bad idea? The signals from the FPGA to the DAC also need a ground return path, so if you force them to flow via the two ground connections to the console, which probably spreads the noise from switching the signals over a larger part of the system.

(Disclaimer: I'm a digital guy too and GCVideo-Lite has noticable pixel clock interference on its DAC outputs, so my attempt to filter the DAC's power supply with a C-L-C configuration failed)

Just by the by: I don't plan on selling my board, I plan on leaving it open and making it easy for anyone to build and program their own

I don't need it, but: Yay! Open hardware is always nicer than some single-vendor closed solution whose supply might stop at any point.

[leonk]

SUCCESS!!!!! I GOT RID OF JAILBARS FROM N64RGB!!

Here's the 2 things you must do:

1) Remove MultiAV port and lift up the 2 GND pins. Protect the existing GND pads from touching the pins (I use electrical tape on pins). Solder socket back down and wires from amp to port. The GND wire now connects above rather than bottom.

IMPORTANT: Both GND pins must tie together. Can't just do 1 and hope cable ties them together!

2) Run short wire from GND pad on N64RGB (next to M A G pads) to frame. I soldered it directly to shield.

All jailbars are gone! Ground loop broken while other ports have single path to ground.

Nice You were faster than my I was with just my reply to your first question!
Have you tried if it is also sufficient to just use point No.2?

no I did not but I see where you're going with this. if I only do number one the jail bars are still there. I guess the extra ground point stops the voltage returning on the single wire to the video encoder. i'm still a bit confused about the fundamentals of what this fixes. The initial thought was that these high spikes were being generated on the amplifier output. what changed?

[Woozle]

In making a third and final revision of my PCB, would this be an adequate isolation of return paths for the two major components of the system?

I'm not talking about the layout, but the use of separate grounds and the 10 ohm resistor linking between the two. Digital electronics is my thing, not analog, so if anyone has a better suggestion, please let me know.

Just by the by: I don't plan on selling my board, I plan on leaving it open and making it easy for anyone to build and program their own, so any contributions are more of a community effort and less "making my private project better". I can set up an order link through Macrofab so you can have a fully assembled and tested board arrive at your door for around $60.

(Drawn using TurdCad)

For Analog Devices ADV7513 they repeatedly suggest using separate analog and digital ground planes with a low impedance connection. Yet on their $600 evaluation board I'm almost certain that they use a single ground plane for everything...

Are you having noise issues on the output?

[CaveManGamer]

Excellent work, Leon! Massive THANK YOU to Leon, Borti and Tim for putting in the time to correct this issue. Truly appreciate the time you guys put in

[mikejmoffitt]

In making a third and final revision of my PCB, would this be an adequate isolation of return paths for the two major components of the system?

I'm not talking about the layout, but the use of separate grounds and the 10 ohm resistor linking between the two. Digital electronics is my thing, not analog, so if anyone has a better suggestion, please let me know.

Just by the by: I don't plan on selling my board, I plan on leaving it open and making it easy for anyone to build and program their own, so any contributions are more of a community effort and less "making my private project better". I can set up an order link through Macrofab so you can have a fully assembled and tested board arrive at your door for around $60.

(Drawn using TurdCad)

Spoiler

For Analog Devices ADV7513 they repeatedly suggest using separate analog and digital ground planes with a low impedance connection. Yet on their $600 evaluation board I'm almost certain that they use a single ground plane for everything...

Are you having noise issues on the output?

With each rev of the board, the noise gets to be less and less, through additional tightly-placed capacitors on the 5V VCC for the ADV7123, and better ground fill coverage on both sides. On my old repurposed-neoVGA-board setup, some very slight jailbars could be seen. When the new boards come in, I'll see how they are.

On my Terasic DE2 dev boards, which have ADV7123 DACs on them, there is no visible noise on anything. For those, ground is just ground for everything, and there's no separate ground.

[holaplaneta]

Excellent work, Leon! Massive THANK YOU to Leon, Borti and Tim for putting in the time to correct this issue. Truly appreciate the time you guys put in

Same here guys!! You are truly the Sleuths of retro gaming tech!!

[borti4938]

no I did not but I see where you're going with this. if I only do number one the jail bars are still there. I guess the extra ground point stops the voltage returning on the single wire to the video encoder. i'm still a bit confused about the fundamentals of what this fixes. The initial thought was that these high spikes were being generated on the amplifier output. what changed?

The noise is caused by the current going to the N64RGB modding PCB. This current needs a return path to the N64 mainboards ground. Lets say you solder just single 'long' wire (with data lines) or maybe a second 'short' wire to the MultiAV for ground connection. Compared to the four short wires for the video signals (assume that you also soldered /CS or /CS75) the one or two wires have a higher resistance.
So the current will take your wires for the video signals as the return path!

I installed two additional GND connection very very close to modding board. In that way the GND-loop becomes very small and the jail bars are eliminated

Spoiler

On my Terasic DE2 dev boards, which have ADV7123 DACs on them, there is no visible noise on anything. For those, ground is just ground for everything, and there's no separate ground.

Yes, terasic doesn't use separate GND planes as far as I remember. Also not on the DE1-SOC kit. But remember that you don't create a loop if you use the dev board.

I don't need it, but: Yay! Open hardware is always nicer than some single-vendor closed solution whose supply might stop at any point.

Mhhhh... Why does the Hi-Def NES and the UltraHDMI came in my mind...???

[mikejmoffitt]

It sounds like adding additional ground connections to the N64 near the analog section would help, then, rather than this bizarro "remove ground from the MultiAV port" stuff.

[leonk]

It sounds like adding additional ground connections to the N64 near the analog section would help, then, rather than this bizarro "remove ground from the MultiAV port" stuff.

the challenge is on! I will restore the port and just add extra gnd.

FYI. When I do NESRGB install, I always add extra GND wire. I should have used my intuition and this might not have been an issue!

[borti4938]

Short story: The better the connection to GND (more and more and short wires) the less noise on the video lines.

[LDigital]

Hey. I have a unit recently Modded by leonk. Its a superb mod and use it on a bvm so don't see any issues. Is there something that needs to be done to avoid long term damage? Cheers

[leonk]

Hey. I have a unit recently Modded by leonk. Its a superb mod and use it on a bvm so don't see any issues. Is there something that needs to be done to avoid long term damage? Cheers

There is no damage done. If you ever move to xrgb or ossc send it in for free fix. BVM ignores the hi speed noise hence why you (nor I) see it on crt.

[copy]

FYI. When I do NESRGB install, I always add extra GND wire. I should have used my intuition and this might not have been an issue!

Would you mind sharing a picture of where you add it, maybe in the NESRGB thread? I'm wondering if that could help the diagonal jail bars I have through s-video.

[leonk]

FYI. When I do NESRGB install, I always add extra GND wire. I should have used my intuition and this might not have been an issue!

Would you mind sharing a picture of where you add it, maybe in the NESRGB thread? I'm wondering if that could help the diagonal jail bars I have through s-video.

I would check where the S-video port was getting it's ground from. Make sure it gets it from one of the gnd pads on the nesrgb board and no where else.

[holaplaneta]

I installed two additional GND connection very very close to modding board. In that way the GND-loop becomes very small and the jail bars are eliminated

Thanks for the pictures Borti. I'm planning on doing this fix tomorrow but I was wondering where the ends of those GND cables should be soldered to.

Did you solder them directly to the aluminum shield? Or is the black cable on the first picture soldered to both the metal plate and to GND on the Multiout?
and is the metal string on the second picture soldered directly to the plastic at the botton of the aluminum plate? Or is it to a screw head?

Cheers and congrats on finding a fix for this issue!

[borti4938]

I use silver bendable wires.
On the modding board they are soldered to the GND pads.

On the N64 they are fixed by
a) the screw, and
b) by the RF shields.
Then I bend the silver wires such that they lie on the big heat sink (the black wire is just soldered to the silver wire, not on the heat sink).
Soldering to the huge heat sink would be better but you need a lot of power / heat to solder anything onto it...

[holaplaneta]

Thank you for the detailed instructions!

I did the mod and it worked beautifully!!! No more jailbars on the framemeister!

[viletim]

borti4938,

I like your idea of connecting the board to the heat sink for a ground connection. I added this as a final step in the N64RGB install guide.

[leonk]

yes Tim. that will fix jailbars on xrgb mini and ossc.

I can confitm that ground doesnt need to be lifted on multiAV port.

[Ikaruga11]

So it's solved?

[crazedbinary]

Just wanted to say thanks to Tim & Borti for such an awesome board and firmware. I recently installed this with Borti's custom IGR firmware and wow this is awesome!

Thanks guys!

Crazedbinary

[leonk]

agreed. difference much more noticeable on xrgb mini than my pvm.

[mikejmoffitt]

I've fixed the 480i "bob" functionality, and a bad bug that made DK64 never use the deblur function.

Working on a detection heuristic next, and then this is feature complete.

[bobrocks95]

I've fixed the 480i "bob" functionality, and a bad bug that made DK64 never use the deblur function.

Working on a detection heuristic next, and then this is feature complete.

Hey mike, will the code for that be publicly available? Thinking about portability to Tim's board once you've got it figured out.

[borti4938]

For some reason he has removed the GitHub repository. To my experience the code would rarely fit into the EPM240T100; however, the board of viletim is also able to carry a EPM570T100 (but with not enogh decoupling caps).
At the moment I'm thinking of publishing my version of the N64RGB board for DIY modders. The board is able to carry MaxII and MaxV CPLDs (Vccint selectable via a jumper), it uses resistor arrays instead of single resistors and it has more filtering components on it incl. for the incomming data lines.

[bobrocks95]

If the heuristic won't fit on Tim's board I'm perfectly fine with IGR activation, but more publicly available options definitely doesn't hurt.

[mikejmoffitt]

Sorry, I'm on the fence about making a proper mod kit so for the time being I'm not distributing the heuristic.

[bobrocks95]

If anyone was waiting on Tim's N64RGB board to be back in stock, it is as of today.

@borti - Just to double-check, if I want to use your IGR firmware, but don't care about reset capabilities, I just wouldn't connect a wire to PIF-NUS pin 27, right?

[Ikaruga11]

If anyone was waiting on Tim's N64RGB board to be back in stock, it is as of today.

@borti - Just to double-check, if I want to use your IGR firmware, but don't care about reset capabilities, I just wouldn't connect a wire to PIF-NUS pin 27, right?

Does it have Borti's newest deblur firmware?