NESRGB board available now

The place for all discussion on gaming hardware
Iraito
Posts: 122
Joined: Sat Aug 24, 2019 8:59 am

Re: NESRGB board available now

Post by Iraito »

I'm planning to buy the NESRGB for my original famicom, The kit i will buy is the one for front loader though (all the extra stuff is too expensive and superfluous for me) so i want to be sure of something. Is the Power/Audio board necessary for famicom ? from looking at the mod it seems to be an extra thing made only to simplify the use of extra plugs and to make the life easier for people wanting to use a more common PSU, personally i don't care about the stereo mod or about sending the audio through a separate jack and i don't care about S-video either.

I'm pretty experienced as a modder and i have a professional de-soldering station that should make my life a lot easier for detaching the PPU, i just want to know if there's any concerning objection at the way i'm going to tackle the mod.
User avatar
ApolloBoy
Posts: 938
Joined: Sat Jan 28, 2012 7:17 pm
Location: San Jose, CA

Re: NESRGB board available now

Post by ApolloBoy »

The power/AV board will really make your life easier, the original Famicom is extremely cramped and having that extra board gives you room to have an RGB output jack. Also, you'll need a special PPU adapter board for the original Fami which the front loader kit doesn't come with and is not sold separately.
Iraito
Posts: 122
Joined: Sat Aug 24, 2019 8:59 am

Re: NESRGB board available now

Post by Iraito »

ApolloBoy wrote:The power/AV board will really make your life easier, the original Famicom is extremely cramped and having that extra board gives you room to have an RGB output jack. Also, you'll need a special PPU adapter board for the original Fami which the front loader kit doesn't come with and is not sold separately.
Oh the adapter board is the easiest part, i will simply solder cables from the socket placed on the motherboard to the PPU fitted in the NESRGB board, the 8pin din can be placed easily (maybe i will use a smaller 9pin one) i can either de-solder the RF female plug and enlarge the hole present or i can drill a new hole and directly connect the wires for RGB\sync\audio\ground\+5 to the RGB plug and place it where the new hole will be.

So there's no danger in doing this i guess ?
viletim
Posts: 550
Joined: Mon Aug 07, 2006 6:44 am
Location: Sydney, Australia
Contact:

Re: NESRGB board available now

Post by viletim »

Iraito,

You can install the NESRGB board into an original Famicom without the new PA board, if you take the following into account.

Power: The heat sink on the voltage regulator is small and gets too hot when the console is powered with a 10V unregulated power supply that it comes with. Replacing the voltage regulator will not change the power dissipation in the slightest, so don't do that. I recommend powering the console with a good quality 7.5V switching power supply. This will reduce the heat dissipated by the regulator by 50% compared to powering it with the original power supply.

Audio: I don't think it's a good idea to use the cartridge audio output to drive the audio cable. The cartridge audio hardware varies, an none of it is designed to drive a capacitive load like a cable as far as I know. It's better to use the audio mixer on the NESRGB board. You can use it as a mixer. That is, connect the A and B inputs to the PPU, connect the cartridge output pin via a resistor to the mixing point (located next to jumper J5). The cartridge input pin needs to be disconnected from the existing mixer circuit on the motherboard. Replace it with a mid supply reference (maybe 4k7 to +5V, 4k7 to ground, bypassed with a 10u capacitor).

Alternatively, you can continue to use the original mixer circuit and just use the NESRGB audio circuit as a buffer. To do this connect the cartridge output through a 27k resistor to the A audio input on the NESRGB board. Leave the B audio input unconnected. This makes the audio circuit into unity gain buffer. You will also probably want to remove C30 as it will attenuate the high frequency signals too much in this configuration.

Image
Iraito
Posts: 122
Joined: Sat Aug 24, 2019 8:59 am

Re: NESRGB board available now

Post by Iraito »

Fantastic! thank you for the tips.
User avatar
FBX
Posts: 2347
Joined: Wed Feb 18, 2015 10:18 am
Location: DFW area, Texas
Contact:

Re: NESRGB board available now

Post by FBX »

@viletim,

Would you be willing to put up a new jumper PDF for the 2.0 boards? I noticed the locations are slightly different than older boards, and I wouldn't want modders to get confused. Cheers!

(my apologies if there's one already up. I couldn't find it)
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

Hello,

I have a new install of the NESRGB in my AV famicom and I'm getting some ghosting while moving quickly.

everything else seems good when using composite sync with universal Nintendo RGB cable.

When using TTL sync on a SNES cable there is bad colours and bars across screen. I'm going to associate this with 75ohm in SNES cable. I think I'm going to buy another SNES cable and remove the 75ohm resistors to see if it resolves that issue.

Thanks
nmalinoski
Posts: 1974
Joined: Wed Jul 19, 2017 1:52 pm

Re: NESRGB board available now

Post by nmalinoski »

Icelvlan wrote:I think I'm going to buy another SNES cable and remove the 75ohm resistors to see if it resolves that issue.
If/when you do this, please ensure that the device receiving the video signals can take TTL sync on its input, otherwise you may burn out something by sending it 5V instead of <1V.
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

I'm connecting to a Gscart then framemeister.

I'm using a Packapunch SNES cable, not sure why regulator sync is not working and need to use ttl sync.

any suggestions?
nmalinoski
Posts: 1974
Joined: Wed Jul 19, 2017 1:52 pm

Re: NESRGB board available now

Post by nmalinoski »

Icelvlan wrote:I'm connecting to a Gscart then framemeister.

I'm using a Packapunch SNES cable, not sure why regulator sync is not working and need to use ttl sync.

any suggestions?
Both the gscartsw and Framemeister are expecting 1Vp-p/75Ohm sync. I think newer gscarts (v5.x) have voltage protection, in which case I expect it wouldn't work, but I don't think you'll damage anything; whereas older gscarts and the Framemeister do not, and you can expect to fry something expensive.

I don't have any experience with the NESRGB, so I can't say for certain; but I would assume a wiring issue. You may need to use shielded wiring for the sync line. (If you're already using shielded wiring, then I'm not sure; someone more knowledgeable/experienced will need to chime in.)
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

From my understanding my setup is fine. Just wondering why my SNES cable is causing jailbars on my screen. I know the colors are off due to the resistors in the cable but didn’t make sense that it would cause it.
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

Edit.
Last edited by Icelvlan on Tue Feb 11, 2020 12:39 am, edited 1 time in total.
User avatar
ApolloBoy
Posts: 938
Joined: Sat Jan 28, 2012 7:17 pm
Location: San Jose, CA

Re: NESRGB board available now

Post by ApolloBoy »

Seems as though Krikzz has been working on a way to get RGB output out of an NES/Famicom without modding: https://twitter.com/krikzz/status/12107 ... 27296?s=20
nmalinoski
Posts: 1974
Joined: Wed Jul 19, 2017 1:52 pm

Re: NESRGB board available now

Post by nmalinoski »

ApolloBoy wrote:Seems as though Krikzz has been working on a way to get RGB output out of an NES/Famicom without modding: https://twitter.com/krikzz/status/12107 ... 27296?s=20
That is really cool, but it looks noisy. I wonder if/how it can be stabilized.
User avatar
Syntax
Posts: 1774
Joined: Wed Aug 09, 2017 12:10 am
Location: Australia

Re: NESRGB board available now

Post by Syntax »

It noisy because its proof of concept. Bare minimum to get a picture from the cart slot.
But for it to work correctly the FPGA needs to emulate parts of the PPU.

Not really my cup of tea, might be some lag involved with the extra processing too but that's my own personal speculation.
User avatar
ceramiclion
Posts: 55
Joined: Thu Dec 22, 2011 11:39 pm

Problems with the NESRGB on an AV Famicom.

Post by ceramiclion »

I recently installed the NESRGB on an AV Famicom and I am having a strange problem. When I try to play a game the main screen flashes for about a second and then only the background color remains. If I try the everdrive N8 I get an "A0 unknown error" or "SD unable to initialize. I have tried to use the AV famicon without the NESRGB attached and the PPU on the motherboard and every game works perfect. Could this be due to a bad unit? Installation was a breeze and I have installed these units in the past with no problem. I find it weird that thee picture looks fine for the half a second it appears on screen.
Thank you.
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

Hi All,

Seems that the jail bars and artifacts on top of the screen never left.

I've tried a bunch of things, but nothing makes them go away.

Here is my setup.
- AV famicom
- framemester
- GSCART

Tried

- re wiring
- different cables (retro access and pack a punch)
- ttl and csync
- bigger wire going to multi out
- bypassing all equipment
- continuity and making sure there are no shorts
- different PSUs
- different PPU

I'm not sure what else to try.
User avatar
Syntax
Posts: 1774
Joined: Wed Aug 09, 2017 12:10 am
Location: Australia

Re: NESRGB board available now

Post by Syntax »

Famicom needs a trace cut else you have composite and csync on the same line doesnt it?
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

No csync is pin 3
User avatar
Syntax
Posts: 1774
Joined: Wed Aug 09, 2017 12:10 am
Location: Australia

Re: NESRGB board available now

Post by Syntax »

With csync wire removed from nesrgb to multiout check if pin 3 still has voltage on it just incase?
User avatar
Syntax
Posts: 1774
Joined: Wed Aug 09, 2017 12:10 am
Location: Australia

Re: NESRGB board available now

Post by Syntax »

How old is the nesrgb? It's not one with the fake LDO regulator is it?
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

It’s the newest revision
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

Tested svideo. This is clear doesn’t look like any issues. Tested ground in cable and console seems good.
User avatar
Syntax
Posts: 1774
Joined: Wed Aug 09, 2017 12:10 am
Location: Australia

Re: NESRGB board available now

Post by Syntax »

Did you remove the csync wire and check if pin 3 still had voltage on it?
User avatar
Link83
Posts: 342
Joined: Tue May 21, 2013 2:39 am

Re: NESRGB board available now

Post by Link83 »

Have you tried:-
-Confirming continuity between MULTI OUT Pin 3 and SCART plug Pin 20
-Checking if any components are present on the SCART cables CSYNC line (Should be straight through from pin 3 if using 75ohm, not TTL)
-Removing the Q1 composite video transistor from the motherboard
-Recapping the motherboard
-Enabling/disabling the NESRGB THS7374's LPF

Also, I haven't seen anybody else do this, but from the look of the NESRGB v2.0 PCB I guess you could also try bypassing the THS7374's RGB output and using the BH7236AF video encoder's RGB output instead, using the via's provided for the Component video add-on board. You would need to use 75ohm resistors in series along with the usual 220uF capacitors in the cable, but I see no reason why it wouldn't work.
Syntax wrote:Did you remove the csync wire and check if pin 3 still had voltage on it?
I'm pretty sure no NTSC systems have voltage on pin 3 - only PAL systems have voltage on pin 3, and even then its only the PAL SNES and PAL GameCube. Some NTSC systems have CSYNC connected to pin 3 (NTSC SNES except for 1CHIP-03/Mini, and early NTSC N64 boards 01->03) but the AV Famicom is not one of them.
Last edited by Link83 on Fri Feb 14, 2020 4:46 pm, edited 16 times in total.
thebigcheese
Posts: 707
Joined: Sun Aug 21, 2016 5:18 pm

Re: NESRGB board available now

Post by thebigcheese »

Probably not the most helpful, but I can say that I have an NESRGB from several years ago at this point that I installed in my toploader (which is, IIRC, nearly identical to the AV Famicom) and have never seen any jailbars. I used a multiout for the output, so it has composite, s-video, and RGBs. Never cut any traces as far as I can remember. If it helps, you can see my install in this video: https://youtu.be/Ww9_NHhMCdQ. I just followed Tim's directions. There's also a follow-up video in the description about removing some capacitors so that you can use a standard SNES cable (per Voultar's advice).

Other advice I have is to make sure you're using good quality wire. I might go a little overkill in my mods using Mogami wire, but I have it lying around and I like to know that it's high quality copper with good shielding so I don't have to worry about interference.

Edit: Sorry, I guess on the AV Famicom you do cut the original composite video trace. US toploader doesn't have that problem since it's RF only.
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

Hmm I didn't think of this.

I'm assuming it's TTL sync coming out of pin 11.

- Should I lift the pin? I can't trace it to the component pinout, looks like the pins are RGB 5V and ground.
- For the resistor, do you mean 75ohm---220uf Cap---CSYNC pin on multi out? No need for resistor to ground?

I haven't tried replacing the caps on the motherboard yet since I thought all the signals were generated from NESRGB, this was a step I was going to do after install.

I tried disabling 7374, no different.
Tried remove Q1.
I verified my smart cables they seem to be good.

I think I might also try a sync stripper on the composite signal.
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

Just tried a different cable - N64 (with sync stripper) and wired it video (both pin 21 and NESRGB separate tests) still getting artifacts at the top of the screen and jailbars.

I don't know what to test anymore.

Could this be the 2.0 vs 2.1 firmware bug?
User avatar
Link83
Posts: 342
Joined: Tue May 21, 2013 2:39 am

Re: NESRGB board available now

Post by Link83 »

Icelvlan wrote:I'm assuming it's TTL sync coming out of pin 11.
No I wasnt suggesting using the video encoder sync output, only the RGB outputs. Are you sure your NESRGB sync jumper J8 is set correctly for your SCART cable. In fact are you sure all your NESRGB jumpers are set correctly?:-
http://etim.net.au/nesrgb/NESRGB-Pinout.pdf
Icelvlan wrote: - Should I lift the pin? I can't trace it to the component pinout, looks like the pins are RGB 5V and ground.
- For the resistor, do you mean 75ohm---220uf Cap---CSYNC pin on multi out? No need for resistor to ground?
No dont lift any pins, all the info you should need is on page 5 of the BH7236AF datasheet:-
https://media.digikey.com/pdf/Data%20Sh ... 240AKV.pdf
Basically you just need to to solder a 75ohm resistor to each of the three RGB vias, and then solder a wire between each resistor to the correct pins on the MULTI OUT. However this is completely untested so should be your last resort - If you have any problems understanding the datasheet then please do not attempt this! (I am not responsible should you fry your NESRGB or AV Famicom!)
Icelvlan wrote: I haven't tried replacing the caps on the motherboard yet since I thought all the signals were generated from NESRGB, this was a step I was going to do after install.
Thats probably the first thing I would try - bad or failing capacitors can cause all sorts of problems. Its good preventive maintenance anyway, plus there are only a handful of caps to replace on the AV Famicom.
Icelvlan wrote:Just tried a different cable - N64 (with sync stripper) and wired it video (both pin 21 and NESRGB separate tests) still getting artifacts at the top of the screen and jailbars.
Have you confirmed there are no components on your SCART cables CSYNC line? You should have a straight though connection with no sync strippers if you have set the NESRGB jumper J8 for 75ohm CSYNC output.
Icelvlan wrote:Could this be the 2.0 vs 2.1 firmware bug?
Firmware 2.2 was released shortly after the NESRGB v2.0 was released, so unless you purchased one of the first batch or two it likely has firmware 2.2 already installed by viletim.

Beyond the above, how have you routed your wires? Some photos of the install would be helpful.
Icelvlan
Posts: 46
Joined: Sat May 21, 2016 1:03 pm

Re: NESRGB board available now

Post by Icelvlan »

I tried updating to 2.2. (assume it was already on this)
Tried using CSYNC from encoder as mentioned, no luck.

Ignore the mess. I've connected and disconnect stuff many times. The extra cable dangling there is an audio cable. I have composite connected right now swell that I tested via N64 cable and sync stripper.

I connected pin 46 and audio via resistors to get extra audio.

My cable has 220uf caps on the RGB lines.

I just tested with 22awg wire and tried copper tape and grounding to PPU
Last edited by Icelvlan on Thu Feb 20, 2020 12:09 am, edited 1 time in total.
Post Reply