Famicom av mod instructions?

[famifan]

hey vlade-1, I actually made the same things

http://www.famicomworld.com/forum/index.php?topic=4713.msg117161#msg117161
http://www.famicomworld.com/forum/index.php?topic=4713.msg112179#msg112179

[vlade-1]

80sFREAK, so you recommend move video cable shield directly to pin 20? And remove 220uF SMD capacitors from those two small chips near joy connectors, and add one to +5V of the amplifier? I will try those.

famifan, as I understand in your mod the shield was the final thing which make no jailbar video output?
In my case only one additional capacitor which I mark as red, takes jailbars away, but the PPU was already shielded. Going to experiment more to check the 80sFREAK hints.

[mushroomsamba]

Hi, I'm new to the forums here please be gentle!  I'm currently working on my first AV mod and I'm having some difficulties. i have attached a picture of what I  have done so far, I'm working on a rev 07 fami and I'm not getting any video output at all. I have tested the transistor and confirmed it is still working and i have triple checked all of the solder points and still no dice  i have tried to follow the 80s freak guide as best i could and tried to avoid making any stupid mistakes. I appreciate any help or advice i can get from anyone here, thanks in advance!

Cheers

Mushroomsamba

[vlade-1]

Hello mushroomsamba, from what I can see, you are trying to take power to your video amplifier from 22 pin.
the 1uF is connecting 22 and 20 pins.
And video signal "lives" in 21 pin.
And the power should be taken from any closest spot on the board.

From your photo I can see you connected R150 to 22 pin.
Look at the http://jpx72.detailne.sk/modd_files/fc/avmod.htm for example of where +5 can be found for your board revision.

[mushroomsamba]

Thanks for the feedback, so if i understand correctly I should connect the 150R to 5 volts from the other source marked in the tutorial instead of pin 22?

Thanks again

-mushroom samba

[jpx72]

Was this page mentioned?
http://vaot.mydns.jp/fc/fcav.htm
In need of translation

[vlade-1]

I have made some tests recently.
My purpose was to check which way is better to get rid of jailbars.
I have already read here some arguments about jailbars and there dependence on TV or cartridge.
Also I have read some opinion that there is no way to get rid of the jailbars at all, because the PPU generates them.

I already wrote about my famicom and soldering some posts earlier.

The reason why I started this test was the video converter, which I used to play famicom on monitor with vga input. While on TV there are no jailbars at all, the converter shows strong jailbars, depends on the game and color. The most bad are in super mario.
At first I thought that this converter is bad. But DVD-player or super famicom shown with no jailbars. So I thought that I need to improve my famicom by soldering something.

So here are the tests. I have checked different video amplifier schemes I have found on the Internet. I have tried to shield the PPU with more solid copper foil and nothing changed. While checking video amplifiers I did figure that jpx72 manual(which based on freak 80's work) shows the simpliest and best amplifier.
At last I removed all modding from the board. And also removed the shield from the PPU.
Then I left only the video amplifier from jpx72 manual, which connected directly to the pin21 which was already removed from board.
No shields nor additional capacitors. After that the image was in terrible jailbars. The jailbars were fat. Something like 20 jailbars over the screen.
Then I added one tantalum capacitor 220uF to the power of video amplifier. And I got the picture which I have begin with when I have got copper screen at PPU and lots of capacitor at power lines. The jailbars are thin looks like they are one pixel wide. So there are like 150 jailbars or smth like this.

I also tried this on the revision 2 of famicom(mine was gpm2) and everything repeated.

So in conclusion I may say that there is no need of additional capacitors on board, but only on video amplifier power. The shielding without desoldering the PPU does nothing.

Later I will try to check more about PPU shielding and desoldering.

By the way I did use the EverdriveN8 cart for testing and some other carts with large chips and with small ones. The jailbars did not changed, only difference in which game it was.

[famifan]

Was this page mentioned?
http://vaot.mydns.jp/fc/fcav.htm
In need of translation

omg! i really do want 'made in japan' ruler as on the pics

[famifan]

But the one thing I didn't was cutting the pin 21 (video) from the main PCB.

ouch! i think it was already known to everyone. Did you ask for help/advice here? or it's just me, am i missed something?
Post Merge: January 14, 2014, 07:07:47 am

This for GPM-02 revision, but others looks almost the same. Notice, that hole for pin21 is empty - pin lifted.

Next stop is remove EMI from surrounding traces on PCB. By some reasons capacitance between pin 21 and others quite big and also producing "jailbars".
> Quote from: GohanX on 2012-07-12, 20:26:16
> I would add lifting/cutting the composite video pin, that made the biggest difference in eliminating jailbars on my system.
Only explanation for this is aging material of PCB or either bad layout of PCB.

from that thread

[blackis]

Hello everybody!

New to famicom modding. My life with nintendo systems started at beginning of 90s, with pal toaster nes.

Now little nostalgia trip has emerged, with buying megadrive 1&2, megacd, 32x, almost all the games to 32x, pal toaster nes (with cic mod), D99 famiclone,  AV famicom and now latest normal famicom (007 revision board, year 1984 printed on it).

I'm not in anyway pro with electronics, but small mods I can do. So first one was to get famicom to output same quality picture as AV famicom. I used this, because it is so simple:

http://nfggames.com/forum2/index.php?topic=4055.0

After i did that, i took sound from 46 pin. And put 3.5mm stereo jack to the famicom. Started rockman 3, nice image, clear audio. But with smb3, yeloow and cyan colors were absent. They were just white! So added a 47 uF capacitor to the video output between resistor and wire to the 3.5mm. Amazing, super colors after that!

Heres a brief video of my mod:

http://www.youtube.com/watch?v=9I9F4owbgRY&feature=youtu.be


And playing:

http://www.youtube.com/watch?v=jGCRJD2wKdY

Only gripe is the jailbars. They are not there with AV famicom, but they are there with the modded famicom. They are not bad, but if a simple fix (more capacitors to the board) can eliminate them, i will be all ears
Post Merge: February 23, 2014, 02:32:31 am
Crappy easyCAP capture device with winavi. Result very crappy looking video

http://www.youtube.com/watch?v=6uJoa8RopPk

Av modded fami vs AV fami. Which is better?
Post Merge: February 24, 2014, 01:21:31 pm
Opened up my D99 Famiclone, It is noac, but the connection to the Video/power board is like the one on famicom, only smaller leads, which got me thinking...Could famicom rf/power board be replaced by that one, and would it work right out og the box...Opinions?

The connector is 5 pin line, like on famicom, it has GND, Vcc, A, VIN, V printed on the Av chip.

[drwily]

I follwed the "new mod" guide on this page: http://jpx72.detailne.sk/modd_files/fc/avmod.htm

I must say, the image quality is top notch, in my opinion. Maybe some slight, slight jailbars, but hardly noticable. I'm happy about the video quality.

My question is regarding the sound, which wasn't succesful at all. There is a buzzing / humming sound, and clearly it reacts to the image. ("black" screen has another frequency of humming than "blue" screen, so to speak). I used shielded cable, and grounded the shielding for both audio and video. I added a 220uF electrolytic capacitor as the guide suggested. I have tried different connections. I have tried routing the audio to my tv, my headset and my music centre. They all get the humming sound.

I live in Europe, and therefore I use a stepdown converter to power the beast.

Here you can see (and hear!) an examble: https://www.youtube.com/watch?v=NUR0-VWNgEs

Any suggestions on how to fix the sound?

[ericj]

Are you sure the humming isn't being generated from the mic volume slider on controller #2?

[drwily]

Are you sure the humming isn't being generated from the mic volume slider on controller #2?

I tried turning the slider down to the click, and I tried unplugging the player 2 controller. Same results.

[famifan]

Any suggestions on how to fix the sound?

i can't hear any humming in sound.

there are only 2 reasons of bad sound:
1) insufficient voltage input (weak PSU) supplied to 7805 voltage regulator. Make sure at least that the supplied voltage from PSU is higher above than 7V under the working condition (i mean the system should be powered up with running game, etc..)
2) spiked noise from PPU/CPU. To fix it you need to add capacitors on power line as they'll act as the power filters. There were pics of how it looks. > http://www.famicomworld.com/forum/index.php?topic=4713.msg112179#msg112179 I'm not sure how much of them really needed, but they probably helps.

[drwily]

i can't hear any humming in sound.

Hmm... There IS humming and a high pitch tone throughout. You should be able to hear the humming more clearly in the "silent" parts when there is no music or sound effects.

there are only 2 reasons of bad sound:
1) insufficient voltage input (weak PSU) supplied to 7805 voltage regulator. Make sure at least that the supplied voltage from PSU is higher above than 7V under the working condition (i mean the system should be powered up with running game, etc..)
2) spiked noise from PPU/CPU. To fix it you need to add capacitors on power line as they'll act as the power filters. There were pics of how it looks. > http://www.famicomworld.com/forum/index.php?topic=4713.msg112179#msg112179 I'm not sure how much of them really needed, but they probably helps.

Thanks! Those are great advices! I will find a way to check it out.
1) How do I check the voltage input? (What piece of equipment do I need?) And if I find the volts to be insufficient/below 7V, how do I "amp it up"?
2) Do you recommend any specific capacitors (type and capacitance) to be added to the power line?

I'm very sorry if these are trivial questions. This mod is my first real sodder-project in more than 15 years, so I'm a bit n00bish