Famicom AV Modification / Mod

[soft]

Not to pile on here, but I've read the entire thread and it seems like there isn't a unified tutorial for this, and that in any case the steps differ depending on the board you're using and the desired effect.

I'm completely new to soldering and this kind of modification, but can learn with ease if the steps are explained.  As it stands, the schematics posted above were about 80% confusing to me.

Below I've posted images of the board I have.  A bit of hand-holding (PM is also welcome) and indications about what parts, where to get them, etc., would be fantastic.  I would be happy to reciprocate the favor by posting my reactions and results upon completion of the mod.

The case lists it as HVC-001, but the sticker states that it be used with DC Adapter HVC-002.  Not sure why there is that discrepancy.
The power supply (?) housing reads: 1.5A SSFB.  I have the original manual with warranty information, and this was purchased in 1991.  I'm not sure of what vintage that makes it.  The stamping on the housing for the power, RF jacks, etc., says copyright 1988.

Please let me know if the attached images are not enough and more detailed shots are needed.  I am not too clear about how to read the PCB.  Does the mod go inside of the metal housing at the back?  If so, that area is not pictured.

Please also let me know if posting images inline like this is verboten.

Thanks in advance.  Fingers crossed on first post,
soft

[jpx72]

Well I will try to make some tutorial, at least for the hardest part - finding the right solder points on your famicom pcb. Then you will have four wires coming out of your famicom and you can then experiment on the rest.
And I really think this thread should be merged with this one:
http://www.famicomworld.com/forum/index.php?topic=4713.0

EDIT:
Tutorial is ready. Video output is on Pin21 of the PPU chip on all original Family computer HVC-001 models (1983-1989) but the placement of the PPU chip on the famicom PCB could be different. Connecting Ground and +5V on the voltage regulator is the same for all original Family computer HVC-001 models (1983-1989). Connecting Sound output could be different on different famicom models.

Also, for soldering newbies - watch this:
http://www.youtube.com/watch?v=I_NU2ruzyc4

The case lists it as HVC-001, but the sticker states that it be used with DC Adapter HVC-002.  Not sure why there is that discrepancy.

The only number that is important here is the PCB model number printed on top of the famicom PCB - yours is HVC-CPU-GPM-02  made in 1989. HVC-002 is the part number of the adapter (the sticker says:"Use only original famicom adapter - part number HVC-002" or something like that). HVC-001 is the main body of the famicom together with controllers.


EDIT2:
According to this thread on nesdev.parodius.com forums,
and according to this famicom schematics
the audio output on every famicom model should be on the cartridge connector pin number 46
EDIT3: I have confirmed that cartridge connector pin number 46 is audio on all famicom and famiclone models.

CONCLUSION:
Video output = pin #21 of PPU
Audio output = pin #46 of Cartridge connector
+5V              = pin# 3 of "7805" voltage regulator
Ground         =  pin# 2 of "7805" voltage regulator

(...now I realized that somebody somewhere surely posted this a long time ago, sorry for that, I was just very excited to find it out myself.)

[cmv2]

Not to pile on here, but I've read the entire thread and it seems like there isn't a unified tutorial for this, and that in any case the steps differ depending on the board you're using and the desired effect.

I'm completely new to soldering and this kind of modification, but can learn with ease if the steps are explained.  As it stands, the schematics posted above were about 80% confusing to me.

Below I've posted images of the board I have.  A bit of hand-holding (PM is also welcome) and indications about what parts, where to get them, etc., would be fantastic.  I would be happy to reciprocate the favor by posting my reactions and results upon completion of the mod.

The case lists it as HVC-001, but the sticker states that it be used with DC Adapter HVC-002.  Not sure why there is that discrepancy.
The power supply (?) housing reads: 1.5A SSFB.  I have the original manual with warranty information, and this was purchased in 1991.  I'm not sure of what vintage that makes it.  The stamping on the housing for the power, RF jacks, etc., says copyright 1988.

Please let me know if the attached images are not enough and more detailed shots are needed.  I am not too clear about how to read the PCB.  Does the mod go inside of the metal housing at the back?  If so, that area is not pictured.

Please also let me know if posting images inline like this is verboten.

Thanks in advance.  Fingers crossed on first post,
soft

I have modified mine with this scheme easily

http://yoshikiyoshiki.hp.infoseek.co.jp/AVFC.html

[io]

Hi,

I'm trying to AV mod a Famicom HVC-001HKG (Hong-Kong Version), motherboard HVC-CPU-NPC-26-01 with a RP2C02G-0.

When I bought it, it was already modde, but the sound was clear but with a low buzz on the background and the picture quality was poor too.

Here is a picture of the original mod :

You can see that sound has no ground. At first I was thinking it was the reason of the buzzing.

Side-by-side pictures to compare with my Sharp Twin Famicom AN-505 (pics on the right side) :



The motherboard :


How I did solder my wires :

I took the same +5 V as the original mod because when the console is switched-off there's no +5 V coming. If I take it from the 7805, I have +5 V as long as the power cord is plugged, no matter the console is on or off, and I don't like this.
I took the ground from the cartridge connector and the audio too (by the way this pin 46 is connected to the point of the original mod too).
I soldered two wires for the video signal, one on the pin 21 of the PPU and the other where it was originally.

On a breed board, I did back the original mod (two 33 kOhm resistors and one C1815), the console worked like before.
Then I tried two others mods, this one and this one too.
For those two mods and with the video signal taken from pin 21 of the PPU I got nothing but a black screen and no sound (it appears that the Famicom only sends sound if video is received on the TV).
But if I use the "original mod video signal", I got a scrambled image and buzzy sound.

If I send the "original mod video signal" directly to TV I got a too bright picture, if I directly send the pin 21 signal video, I got a dark picture.

If I send the "original mod video signal" through a 75 Ohm metal resistor I get something nice but there are some parasites like moiré all other the screen (like for the original mod, but with a better picture) and the sound is still buzzy. I did try a 220 µF with the resistor, but it changed nothing neither for the video nor the sound.

Thanks a lot for any help, answer, advice.

Gallery pictures here : http://jomay.free.fr/Famicom_HK_AV_Mod/

[ericj]

The buzzing is probably caused from the Player 2 microphone volume control. Try unplugging the controller from the PCB or moving the slider around and see if it stops.

[io]

The buzzing is still there even if I remove the second controller

But what I find strange is that I can't have the same result as the others with the video from pin 21.

[io]

Nobody can help ?

At least, is the mod for the HK board the same as the one for the japanese board ?

Thanks.

[jpx72]

Bumping this topic again, this time for a friend who is searching for a solution to a curious problem. I'm forwarding the email I got:
-------------------------
I'm a brand new and happy owner of a Famicom and wanted to modify it to make it usable on my TV (I'm living in France).
After doing researches online and comparing the different modification methods, I decided to make yours, as it seemed for me the clearest, most recent and universal one (I understand this is the kyuusaku's schematics we're talking about)
Anyway, what I get is a (clear, anyway) image that is black and white. This is the first time I experience problems with japanese consoles as I play many other ones (like the PC Engine) in colour on the 2 TVs I have.
So I decided to buy a Pal > NTSC converter but the picture is still in b&w on my 2 TVs.
I was wondering if you heard about similar issues and if you can use directly your Famicom on your TV without using a signal converter (as I guess we got the same TV standard in Europe).
-----------------------
If the TV displays other NTSC consoles fine, I don't understand why the Famicom has B/W picture. Any help appreciated!

[Xious]

P.M. sent...

[kyapiko]

This is my first post here so Hi everyone !

I'm the guy jpx72 is talking about.
I've tried my modded Famicom on 6 TVs (in which a pretty recent LCD TV which clearly accept NTSC).

I've tried this mod : http://jpx72.detailne.sk/modd_files/fc/avmod.htm
Then this one : http://www.h3.dion.ne.jp/~kuboken/famicom/famav2.html
I also tried plugging directly the video out from the motherboard to the RCA cable without putting the video amplifier and I always get a B&W picture (with the better image quality from jpx72's mod).

Something I could add is that on the first attempt to mod it (with Kyuusaku's schematics), as there was not a clear model of transistor written, I just asked the electronics shop to give me a PNP transistor (5-15V) but they gave me an NPN ! (I noticed that after trying the mod).
Of course it didn't work so I redid it successfully after putting properly a 2N3906 I found on an old PC motherboard (while getting a B&W picture of course).
So after all, I'm guessing if this hasn't damaged something...

Well, starting to be to be discouraged, I just ordered an AV Famicom in order to fully enjoy playing at this mythic console. I'll keep trying to find a solution to get my old Famicom fully working anyway...

By the way, thanks to everybody involved into these mods and everything.

[XIXO123]

Try with the link http://www.briconsola.com/esp/p23.htm

http://translate.google.com/translate?hl=es&sl=auto&tl=en&u=http%3A%2F%2Fwww.briconsola.com%2Fesp%2Fp23.htm



He takes pin 1 and 2 together, but I connected it to the R and the L of the CPU to the sound to get Stereo effect. I proved it and it works. The problem is that I can´t get video signal in old TV, I don´t know the reason why.



Look also in http://www.famicomworld.com/forum/index.php?topic=4713.0

[fredJ]

Maybe this thread could be moved to the    Technical & Repair Assistance category.

[UglyJoe]

Moved.

[P]

I have problems with an AV modded Hong Kong Famicom showing a bad picture and sound effects seems to be a bit off.

There's way too much red as can be seen here:

img upload

It's the version with the unlicensed Makko Toys RF-modulator (described here http://www.famicomworld.com/forum/index.php?topic=4138.0):

free image hosting

HVC-CPU-07:

img upload

Those black AV cables are tucked in through the slot that is normally used by the channel 1 and 2 switch on a normal RF-modulator. The red and white power switch cables also goes to this board:

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Makko Toys with the Family Game logo:

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The AV cables are soldered directly to the underside of the two boards:

img upload

I've tested the AV cables with the "beep function" on my multimeter and they seem to be allright.

[2A03]

I'd just redo the entire mod and use what's outlined in this thread by Da_Bear and others.