Sharp Famicom Twin RGB mod

[Arasoi]

Hey guys,

I originally was linked here by a friend while looking for RGB port pinouts for a few systems (which I made cables from as a reference). I've been reading all of the great NES/Famicom RGB threads on this site (and a couple others) and I've decided to RGB mod my Sharp AN-505 FCTWIN myself with a Duck hunt or PC10 PPU,  minor graphics issues or not.

I wasnt able to find a topic with the search function with the info I'm looking for, so here goes.

Im not sure which chip on in the motherboard is the PPU, I've narrowed it down to 2 candidates (sorry for the picture quality):



They both seem to have the right number of pins. The top circled one is labeled RP2A03E, the bottom one is under a heatsink and marked R1292CE on top of said heatsink.

Has anyone modded one of these units, or know which PPU I need to de-solder for this? I would assume all the caveats still apply (lift the proper pins off ground, ground the proper pins, signal booster, etc)

Any help appreciated, as I'd like to get a crisp RGB picture on my NEC XM29.

Any help greatly appreciated;

- RCM

[NeWmAn]

Im not sure which chip on in the motherboard is the PPU

It's the one with the heatsink, closer to the cart connector.

[Arasoi]

Excellent, thanks for your help.  It looks like I'll have to take out the cart slot temporarily to do the mod, but that shouldn't be an issue.

[RGB32E]

Any help appreciated, as I'd like to get a crisp RGB picture on my NEC XM29.

Any help greatly appreciated;

- RCM

You could just hook up a PC or console emulator to one of the RGB inputs on your XM29, connect a modded NES controller (parallel port or usb), and call it good, right?

I recently RGB moded my NES, and the results are pretty good for older games.  However, newer games, such as Crystalis, are really bad.  I think it has something to do with the missing intensity palette functionality on some PPUs?

[Arasoi]

I own about 200 Famicom games (disk and cartridge) and about 50 NES carts i play through a 72-60 pin adapter. I've got a PC plugged into the XM29's RGB1 port but I only use it for playing handheld game/ROMs. I prefer using the original hardware when possible (I don't really enjoy  playing handhelds anymore)

At any rate I'm going to be buying an orange AN-505-RD anyway so my current red one will be for RGB.

[RGB32E]

I own about 200 Famicom games (disk and cartridge) and about 50 NES carts i play through a 72-60 pin adapter. I've got a PC plugged into the XM29's RGB1 port but I only use it for playing handheld game/ROMs. I prefer using the original hardware when possible (I don't really enjoy  playing handhelds anymore)

At any rate I'm going to be buying an orange AN-505-RD anyway so my current red one will be for RGB.

I was kinda kidding around about the emu route... I wouldn't have purchased a XRGB-3 for my 55" TV if I didn't prefer using real HW!

Do you know of any places to purchase a 60->72 pin adapter (reverse of the one you've mentioned)?  I have a gyromite cart that contains a 60 to 72 pin adapter built in the NES cart (during that shortage in the early days of the US NES), but I wasn't sure what the correct card orientation is... I don't want to ruin any HW...

[Arasoi]

You got me on the emulator thing, I've heard it so many times I've got a bit of a knee jerk reaction lol.

Anyway I managed to dig up a link to someone selling decent 60-72 adapters:

http://www.robwebb1.plus.com/nes/nes.htm

It's farther down on the page, if you don't mind ordering from the UK this should fit the bill. Not sure what it means by requiring a modded NES, none of the ones I know of require this.

Hopefully that helps anyway.

[RGB32E]

I built a different amp for the NES and now have really good RGB output from my NES!  I've also figured out how to greatly reduce jail bars as well by adding a low pass filter!  The filter I use works much better than the LPF in the XRGB-3, and it gives me the ability to use the system on a regular RGB monitor!  I'm still tweaking the filter values to get it just right though, so that the artifacts can be completely removed from the video signals...

[Arasoi]

Very interesting. I just ordered a few IC sockets today, so I'll be doing mine pretty soon. Would your different circuit be helpful to someone looking to just hook up to an NEC XM29? (low res, no scaling/conversion).

Due to case space restraints in the Sharp Twin I think I'll need to build my amp outside the case, I wonder if theres any external device you can get for this or if it needs to be custom.

[NeWmAn]

Due to case space restraints in the Sharp Twin I think I'll need to build my amp outside the

Are you serious? If there's one thing the Twin units are good for is proving a big and spacious case.
There's plenty of space inside to place everything and please, when it comes to get the RGB signal to your monitor, don't add a stupid additional plug but rewire the RF modulator DIN connector instead.

I've also figured out how to greatly reduce jail bars as well by adding a low pass filter!

Could you explain (and maybe post a picture) of the problems you were getting with the old amplifier?

[Arasoi]

If there's one thing the Twin units are good for is  providing*  a big and spacious case.
There's plenty of space inside to place everything and please, when it comes to get the RGB signal to your monitor, don't add a stupid additional plug but rewire the RF modulator DIN connector instead.

The plan was to rewire that 8 POL DIN to the same pinout that Genesis/Master System/etc uses for convenience sake. Concerning the space inside of the Twin, I suppose so. I have other less complex mods planned that will push the envelope with space so I'm planning ahead. I'm not fond of the idea of  building it externally, but if I do I can use it to amp other systems that require it (Duo-R, possibly N64).

[RGB32E]

Could you explain (and maybe post a picture) of the problems you were getting with the old amplifier?

With the Moosman amp I encountered a number of issues.  I was using the exact same BC transistors (when I realized that the NTE equivalents were 180), the first issues I noticed were:
1. Bleeding to the right (only on to black areas on the screen)
2. Some general noise
3. Vertical lines every 8 or 16 pixels across the screen (jail bars) along with fainter lines in between (similar to the NEC PCE/TG systems)
4. RGB signal seemed too strong
5. Color balance to shifts depending upon how much of a given R, G, B levels were on screen.

Adding 220uF electrolytics in series with the 47 ohm output resistor cured problem 1.  Changing the output resistor from 47 to 75 ohms fixed #4, but increased visibility of #3.  Overall, the amp made the project a bit of a disappointment at first.  

When playing Crystalis, the initial white background of the SNK splash screen was grey instead of white.  When playing in game, the main character changed between the normal purple palette to blue, depending upon screen content (background colors, ect).  When playing Bionic Commando, area 5 (I believe - the tall tower stage with a red background/sky color), the image would change color balance depending upon the amount of bright red on the screen.  Ick....

I know that with some CRT monitors that most people wouldn't even see the jail bars.  Point being, that depending upon the monitor, some people wouldn't even notice.  However, the amp I'm using now is pretty much as good as it will get...

Here is a crappy camera pic of what my RGB modded NES currently looks like:

(NES RGB -> XRGB-3 D2 input (RGB) in B0 mode @ 1920x1080 -> Sony XBR8 PC Input)

[NeWmAn]

That's a really nice picture!

I've built 2x Moosmann colorboosters and I too get a little of bleeding and noise, but I haven't noticed problems 4 and 5.
I also see some jail bars, but what's puzzling me is that the problem is visible only with some colors.
I thought it could be crosstalk between the data lines and the RGB lines, hoped someone could confirm that.

Your modifications ideas are interesting, but are you still using the Moosmann amp (with your mods) or have you installed something else?

[RGB32E]

That's a really nice picture!

I've built 2x Moosmann colorboosters and I too get a little of bleeding and noise, but I haven't noticed problems 4 and 5.
I also see some jail bars, but what's puzzling me is that the problem is visible only with some colors.
I thought it could be crosstalk between the data lines and the RGB lines, hoped someone could confirm that.

Your modifications ideas are interesting, but are you still using the Moosmann amp (with your mods) or have you installed something else?

The picture is with a different amp.  I'm thinking #5 has to do with my solution to #4, but I cannot say for certain.

Jail bar intensity and variation are dependent upon what the software is doing.  So, some games have the main jail bars on a completely black screen, others do not.

[Moosmann]

If the RGB Signal to strong, please use a little higher resistor (75 Ohm instead 47 Ohm or a 100 Ohm Poti) for output.  Contrast and brightness is to adjust on the TV, so that the jail bars are not visible to the black background. If you have a XRGB-3, please use LPF to reduce them a little.  I don`t see the jail bars on the C1 Television (afair), maybe a little other modification is required. I don`t have the datasheet from C1 here, maybe anybody can send me them, so that I can compare differences.

My Blog isn`t updated the last time with Flashcard compatibility and Action Replay Codes, because I don`t have the timne at the mopment

Greetings Markus

[RGB32E]

If the RGB Signal to strong, please use a little higher resistor (75 Ohm instead 47 Ohm or a 100 Ohm Poti) for output.  Contrast and brightness is to adjust on the TV, so that the jail bars are not visible to the black background. If you have a XRGB-3, please use LPF to reduce them a little.  I don`t see the jail bars on the C1 Television (afair), maybe a little other modification is required. I don`t have the datasheet from C1 here, maybe anybody can send me them, so that I can compare differences.

I tried a 75 ohm resistor.  I did notice that I could reduce visible artifacts by lowering the brightness on my TV.  The LPF works, but with a different amp design, I can reduce the jail bars without the artifacts that the XRGB-3 adds with LPF enabled.  I still don't know why the color shifting occurs when I use your amp.      Perhaps adding a decoupling capacitor between GND and 5VDC might fix that.

[Moosmann]

I don`t have problems with my XRGB-3 and the amp, but please send me your different amp design to compare.

Greetings Markus

[RGB32E]

I don`t have problems with my XRGB-3 and the amp, but please send me your different amp design to compare.

Greetings Markus

I'll be updating the wiki with a better solution for "me" very soon!

[Moosmann]

Which Firmware do you have on your XRGB3 ? I updated the newest FW and I got vertikal stripes lines, but this is a bug in the new FW.

BTW: The XRGB3 is very buggy,  it don`t display 480p from my US Wii correctly and so on....but i still try to get a picture with the right set up.

Greetings Markus

[RGB32E]

Which Firmware do you have on your XRGB3 ? I updated the newest FW and I got vertikal stripes lines, but this is a bug in the new FW.

BTW: The XRGB3 is very buggy,  it don`t display 480p from my US Wii correctly and so on....but i still try to get a picture with the right set up.

Greetings Markus

I have the latest FW... 2.12, but the issue with the NES is independent of the XRGB-3...

Besides, on the XRGB-3, adjusting the black level from the default 128 value to 121 reduces vertical noise present on the signal, especially on black backgrounds.  

I've seen japanese RGB kits that have the amp circuit on a PCB that connects the PPU via a very short circuit route... hmm....

I'm not saying that the XRGB-3 doesn't have it's own set of quirks.... just that the issue with the NES isn't one of them...    Perhaps a re-engineering of the NES power components would help (upgrades to the AC power supply, voltage regulator upgrades, and better RF filtering).

I've been able to run 480p from my US Wii through the XRGB via the official Japanese D-Terminal cable using both B0 and B1 modes...    However, I prefer to connect the Wii directly to my TV with official component cables, or use a standalone converter (Component -> RGBHV).

[Arasoi]

I know this is an old topic, but I wanted to show what came of all this.

At the time this mod was a tad out of my league, so I contracted the work out.

1 Sharp Famicom Twin AN-505RD, RGB modded.

DewmanSNK performed this mod to my specifications and it turned out great. After the PPU switch and amp install, he replaced the small RF 5 pol din connector with a Megadrive/Genesis/SMS 8 pol din connector, and wired the RGB and sound with the Megadrive/Genesis/SMS pinout. Any standard Megadrive SCART(or otherwise) RGB cable works out of the box with this system.  It uses an ultimarc RGB amp with a JROK sync cleaner.

On my end, I replaced the broken FDS drive and  gutted an old PS2-Neo Geo controller adapter and made an adapter to use my NES 4 score through the 15 pin expansion port. No more short controller wires. Well, unless you need the player 2 mic. But that's rare.






Very nice result overall. Very crisp/nice picture on my PVM 20N2U.

[undamned]

I've seen japanese RGB kits that have the amp circuit on a PCB that connects the PPU via a very short circuit route... hmm....

Makes good sense.  Running lengthy unshielded RGB wires from the PPU to the amp is perfect opportunity for noise.  RGB wires act like antennae picking up noise and then on top of that it gets amplified.

NES 4 score

Any reason you chose this over the NES Satellite?  I always wanted to try one of those...

I've been commissioned to do an NES RGB mod, so I'm super pumped to finally be able to do this.  I've had a hand full of RGB PPU's for a while now, but always seem to get involved in some other project.  Somebody paying me to do the project is motivation enough  
-ud

[Arasoi]

I chose the NES 4 score because it's what I had lying around basically. The satellite probably works just as well.

It should be noted the FDS functions are kaput if you do this mod, at least on the Sharp Twin. I have a spare unmodded AN500 I use for FDS or incompatible games though.

[Arasoi]

For those interested, I discovered the following:

The resistor mod described here:

http://nfggames.com/forum2/index.php?topic=187.msg14551#msg14551

Is necessary to resolve graphics issues on some games with the Famicom. As described later in the same thread It isnt necessary on a regular NES deck, only the second model and the Sharp Twin as well.

It does not resolve the graphics problems with FDS games, but it is a good start.

[Elrinth]

I know I'm not supposed to revive dead topics. (Users probably aren't here  any longer either)

I'd like to know how to mod the four score so it can connect to my Sharp Twin Famicom.
I've got a four score and a Neo Geo/Famicom port cable. Now what? What's the wiring?
I just improvise?

[Drakon]

It should be noted the FDS functions are kaput if you do this mod, at least on the Sharp Twin. I have a spare unmodded AN500 I use for FDS or incompatible games though.

B.S.







The FDS in a twin works fine with a proper rgb mod.

[gojirien]

Hi,

A friend of mine's currently doing this mod with my twin famicom.

I was wondering where to get the +5V signal for powering RGB amp, we only have -5V on the console.