Hello!
I recently stumbled upon this mod on YouTube:
https://youtu.be/ky8rFPbzGMU
It seems pretty good! I was looking into it, I have a console coming from Japan, I own a soldering kit, and I can easily get the parts; but I have a fair few questions regarding the build, so I'll start at the beginning and hope someone can answer them.
1) If I were to solder AV cables directly to the board/resistor/capacitor, would I need to ground a third cable, or simply keep the audio and video with only one audio channel? It looks to me like the only thing being grounded is the jack, as the second audio channel is a duplicate as opposed to actual surround. I don't mind the cables being permanent as the controllers already are, and would rather bypass the jack as it feels like an unnecessary extra component.
2) Does the wattage of the resistor matter at all? The highest one I can find is either 3W or 5W, and I read elsewhere that the system's power adaptor is 8W and I'll be using a SEGA Mega Drive adaptor which clocks in at 12W maximum output.
3) If I were to get a different version of the board (I'll update later if I do), where would the Audio and Video out points be? I asked the creator of the mod and they did say it should work with other board revisions assuming one can find the correct points to solder to.(This one might not be necessary, as I've heard the GPM-2 revision is the most commonly found one and I'm hoping that's the one I've bought, but you can never be certain and sellers never list it.)
4) Mainly for curiosity, is that seriously it??? Three caps and a resistor seems awfully simple for an output mod compared to other schematics I've seen. I really hope it works, as it's my first modding job and I would much prefer something simple.
If anybody could answer any of these I would be incredibly grateful, and it would help loads :D I didn't order the RF or power cords with the system, and having PAL TVs is a nightmare enough so I figured AV was just the best option as I definitely have spare cables lying around.
Thank you in advance!! ;D
1) just use 2 wires for audio jack and 2 wires for video ,that all
2) the wattage does not meter, use the tiniest one resistor like 1/8 W is enough
3) the Audio is always in pin 46 from the cartage slot on any revision, but the video is not, you have to trace it down from pin 21 on the PPU
4) yes it is very simple , there is a slightly complicated scheme with one additional transistor, but is can work on any famicom NES or famicone even NOACs here
https://drive.google.com/file/d/1EQRmeMO1W0WFJ3EWKj9Z5l3DMet4eLTV/view?usp=sharing
Quote from: SlumberingWeird on June 05, 2020, 10:26:40 amI didn't order the RF or power cords with the system, and having PAL TVs is a nightmare enough so I figured AV was just the best option as I definitely have spare cables lying around.
You are out of luck if your TV only supports PAL! TV has to be NTSC or multi-region !
Quote from: FAMICOM_87 on June 05, 2020, 12:09:59 pm1) just use 2 wires for audio jack and 2 wires for video ,that all
2) the wattage does not meter, use the tiniest one resistor like 1/8 W is enough
3) the Audio is always in pin 46 from the cartage slot on any revision, but the video is not, you have to trace it down from pin 21 on the PPU
4) yes it is very simple , there is a slightly complicated scheme with one additional transistor, but is can work on any famicom NES or famicone even NOACs here
https://drive.google.com/file/d/1EQRmeMO1W0WFJ3EWKj9Z5l3DMet4eLTV/view?usp=sharing
This helped a lot, thank you!! I'm a complete novice, so I've no idea what a PPU even is, where a 5V line would be, or how to wire any of it up in parallel, but I'm sure with a bit of asking about I could figure it out. I'll at least be able to find pin 46 from the slot, that's easy enough and is very handy to know.
I'll probably update this thread with the PCB number I get if it's not GPU-1 or GPU-2 (As far as I'm aware they're pretty similar) and ask for a little more help then.
And no worries about the PAL TV, all the TVs in the house are fairly modern and do support a 60 hertz signal, so it isn't the end of the world if the mod fails, but my NES uses AV cables as well and I'd rather not pay more money for the RF cable when I already have at least two sets of spare AV cables.
The PPU is the video chip in the Famicom designed by Nintendo, possibly inspired from Namco's Galaxian arcade system (which inspired Nintendo arcade systems like Donkey Kong) and common video chips like the TMS9918. It's sprite- and tile-based and is what gives games the characteristic Famicom look.
Even if your TVs support 60 Hz framerate and NTSC colour encoding, chances that they support NTSC via RF are low. Or did you already test RF?
Quote from: P on June 05, 2020, 11:38:06 pmThe PPU is the video chip in the Famicom designed by Nintendo, possibly inspired from Namco's Galaxian arcade system (which inspired Nintendo arcade systems like Donkey Kong) and common video chips like the TMS9918. It's sprite- and tile-based and is what gives games the characteristic Famicom look.
Even if your TVs support 60 Hz framerate and NTSC colour encoding, chances that they support NTSC via RF are low. Or did you already test RF?
That makes sense I guess, thanks.
I have tried it with PAL RF, I've an old PS2, but I don't own any NTSC systems above a couple DS consoles. I guess I'll see what happens if the mod fails.
UPDATES:
I've got myself a CPU-007 board revision. I've no idea where any of the solder points might be, or if I'll need extra parts or wires to get to or between them.
I can see five square points labelled as GND, VIDEO, CLK, VCC, and SOU, would these be the correct points? I can probably guess which is ground, video out, and audio out, being GND, VIDEO, and SOU, but I'd rather not proceed without proper confirmation. I've no idea where a "46 from the cartridge slot" is either, and my only guess at it doesn't look like it connects to anything. I should also add that I'd prefer not to cut Pin 21 as that disables the RF, and even if I don't use it I would prefer the console to still have all its functions.
If somebody could please help that would be great! (Diagrams a plus, I'm really quite clueless here :-[ )
give me a photo of your famicom board from soldering side and I will draw you where and what you have to solder ;)
Quote from: FAMICOM_87 on June 12, 2020, 10:25:31 amgive me a photo of your famicom board from soldering side and I will draw you where and what you have to solder ;)
Thank you! This is it here, it's a Twitter link because that was easier
https://twitter.com/SlumberingWeird/status/1271536371337965573?s=20
Thanks again!
Here you are :) 47uF cap is optional for reducing the vertical lines (jailbars)
the caps can be higher voltages as well for example 10V if you can not find any 6.3V
The resistors are 100 ohms and 150 ohms can be 1/8 Watts or 1/4 Watts
the transistor can be any PNP
for example https://www.addicore.com/2N3906-PNP-Amplifier-Transistor-p/152.htm
Be careful for the pin out - Base, Emitter, Collector ! diffident models have diffident pin outs !
good luck :)
Quote from: FAMICOM_87 on June 12, 2020, 02:39:45 pmHere you are :) 47uF cap is optional for reducing the vertical lines (jailbars)
the caps can be higher voltages as well for example 10V if you can not find any 6.3V
The resistors are 100 ohms and 150 ohms can be 1/8 Watts or 1/4 Watts
the transistor can be any PNP
for example https://www.addicore.com/2N3906-PNP-Amplifier-Transistor-p/152.htm
Be careful for the pin out - Base, Emitter, Collector ! diffident models have diffident pin outs !
good luck :)
Thank you so so much!! I think I'll try it without the 47uF first, but I can always change that if it's bad. I'll order the parts and get on it, and will give a small update on how well it goes!
The smallest capacitors I can find are 16v, would those work?
Thanks again!
Yes of course, any voltage above 5 V will work for the Caps on the board :)
you can search for any other general purpose PNP transistor (even you can use the same model on the board) if can not find that from my example. Yes you can add this 47uF temporary to see if there any improvement for you and if you are not satisfied remove it :)
Hi,
if I do this mod on a version 07 Famicom, do I need first to desolder the transistor from the board? Or I can keep it where it is and add another transistor and connect it like picture above?
Do not remove anything, just add the MOD :) And you will keep the RF functionality as well :) ;)
Hi,
yes I kept it as it! Thanks!
I did not do the jail bar mod at first, and the jail bars were BAD. With the mod above with 47uF cap it reduced it significantly to the point I was OK with it. Maybe I can reduce it further but without doing any destructive operation on it, what would be the recommendation if any? Again I am quite OK with it now.
The problem I had was severe buzz sound from audio out. I had no idea what it was. Then I noticed MIC volume is at highest setting so I set it to lowest and the audio buzz was more or less eliminated.
I am quite satisified with the mod and used this thread to do the work. Thanks FAMICOM_87 :)
yes the buzzing is usually from the mic. Just cleane the graphite sliders on the joystick 2 PCB and with a very fine sandpaper about 2500 do the metal springy slider thing.
About the further improvements on the mod without cutting the pin 21 or trace from it to the the original transistor .
I read in some threads that you can add a 22mF inductor in series right before the center pin on the video RCA to reducing jail bars even more, but I did not tested this yet, because do not have the inductor with similar parameter :)
Hi,
I did the mod on a HVC-CPU-07. I used a BC557B instead of 2N3906 (friend have already some of them...)
I'm quite happy with the output, I mean it's better than what I was expecting.
There is still more or less some jailbars depending on the color of the background, worst is probably SMB3, but it's not outstanding.
However, very top and bottom of picture is missing. Is there something I can do ? Any idea ?
I have only one CRT TV (trinitron) for testing, I never had such important issue with other devices. I assume TV settings are OK.
Check how to change the image geometry on your TV. You might need the remote to access the service menu. Some TV-sets actually has knobs for changing some things but this is mostly found on monitors and some very old TV-sets.
But if other devices are fine, it might be the AV-mod that is the culprit.
Does your other devices use the same signal as the Famicom? By that I mean NTSC composite. Some TV-sets may store different settings for different types of signals, meaning that even if the geometry is fine for PAL you may need to change it for NTSC (assuming your TV supports both PAL and NTSC).
TV supports both PAL/NTSC, SECAM also, but you are pointing something, I have no issue with NTSC, but it's not composite NTSC. Other devices are RGB.
This TV have a service menu with dozens of settings, including geometry and lots of things I don't understand, but as far as I remember, they don't look specifics to the input. I will check again.
Unfortunately, I don't have anymore another TV to try out. Also OSSC won't work with composite.
A seems like a very good TV, you may want to look up how to change geometry on the internet, there are probably youtube videos with similar settings as found on your TV. If you have some sort of flashcartridge solution for your Famicom (or about any other console) you can use the 240p Test Suite (https://junkerhq.net/xrgb/index.php?title=240p_test_suite#NES.2FFamicom) to generate a test picture that you can use to see what is considered overscan and what is action safe display area. You then adjust the picture until the overscan area is more or less just outside the screen. There is no one perfect setting, especially not for Famicom/NES as games very often shows more or less artifacts at the edges when scrolling, so you would have to keep that in mind. If you crop out too much overscan some games will have the status bar outside the screen. Edge garbage is a characteristic of the Famicom so some overscan is unavoidable.
Yeah if the TV supports that many different signals it only makes sense that it would store different geometry setting profiles for NTSC, PAL, SECAM, RGB 60 Hz, RGB 50 Hz etc.
"NTSC RGB" of course doesn't make sense since NTSC is a type of analog color encoding used in RF/composite/S-video (while RGB equals no color encoding), but I guess your TV may store different setting profiles for 60 Hz RGB signals and 50 Hz RGB signals, since a 50 Hz RGB video source probably uses PAL timing for hsync while a 60 Hz RGB video source uses NTSC timing for hsync. The different hsync timing would make the picture a bit too much to the left or right if they use the same settings, so it makes sense to store separate settings, I know my CRT does.
Thanks for the explanation, and the ideas !
I could find information that confirm TV supports NTSC4.43 and NTSC3.58
I don't have any flashcartridge for the famicom, but I can use my PC-Engine (RGB) as I see a 240p suite is available.
This is even better, I will see if settings for the famicom affect the PCE
I will try today or tomorrow...
problem solved
hum.... this was actually VERY stupid
this is 16/9 TV, so it has one feature to make 4/3 looks like 16/9 by cropping a little bit top/bottow and streching right/left
when input is RGB, it switches automatically to full 16/9
when input is composite, it does nothing and keep actual setting ... that's the reason why very top/bottow was missing
240p test shows also geometry is not perfect, and red tends to bleed on the left.
I will try service menu, but 25 years old caps might not help, and geometry/color has never been perfect even when it was new.
So finally, the mod works very fine, with limited failbars :)
If you have a scart on your TV you can force it to change the mode by one of the scart pins:
"Pin 8, the function switching pin, carries a low frequency (less than 50Hz) signal from the source that indicates the type of video present.
0V-2V means no signal, or internal bypass
4.5V-7V (nominal 6V) means a widescreen (16:9) signal
9.5V-12V (nominal 12V) means a normal (4:3) signal"
(Taken from: https://pinouts.ru/Audio-Video-Hardware/Scart.shtml )
yes, maybe useful to somebody.
I will keep as it is, I just have to remember to force to 4/3 ...
I used a TRRS jack, so no more space for additional wire.
Oh widescreen, it's truly a very good TV. Take good care of it.
Is it the audio and video are not already boosted/filtered? Why use additional components?
Quote from: FAMICOM_87 on March 06, 2023, 11:47:03 amI read in some threads that you can add a 22mF inductor in series right before the center pin on the video RCA to reducing jail bars even more
Hi,
Have you a link to this thread ?
Looks something wrong, if it's an inductor, it should rather be mH
if it's a capacitor, 22mF is not an usual value...
I do not remember from where I read that. And yes my bad, it is 22μH (Microhenry) ! you can try with other values like 10 to 30 for example as well, and pick the best one for your taste :)
Edit here you are :
https://www.reddit.com/r/Famicom/comments/jvp5th/my_new_trick_to_reduce_jail_bars_and_harsh_edges/