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This
is a mod for an old model Famicom (HVC-001) to add RCA audio and video
outputs on it. The main reason that one would implement this mod is
primarily for improved video quality. Another reason for this would
be because the Japanese TV standard. While it is still NTSC, their
cable TV frequency ranges run different from American ranges (due to FCC
and VCCI [Japan’s] standards), so the Famicom’s RF modulator’s
channels are labeled ch1-2, and show up on channels in the 96-97 (correct
me if I’m wrong). This may not be a problem with some people, but
many people’s TVs do not go up to that range, so this poses a problem to
many Famicom fans. It’s based off of a mod that was on a Japanese
site which has since gone down and has been previously unavailable in an
English language version (only choppy translations from altavista.co.jp).
WARNING:
This mod will involve you opening up your precious Family Computer and
Soldering Components onto the CPU and the bridge adaptor on the
Motherboard which could potentially lead to one frying their Famicom.
That is why it will require basic knowledge of electric circuits and some
skills with a soldering iron. You will also be required to know how
to read a schematic diagram in order to build the circuit.
I
will not, nor will the site (Famicom World), be held responsible
for any damage you do to your Famicom while performing this modification.
If you don’t have confidence in your abilities, give it to someone else.
Hell, if the demand ever gets high enough, I’ll do mods for a small
charge, parts cost, and shipping fees.
Supplies
Needed:
-
1
Soldering Iron
-
1
pair of dykes (wire cutters)
-
1
Pair of Wire strippers (optional)
-
1
roll of Solder (the finer, the better)
-
1
Soldering Iron Cleaner/A Sponge (Optional, but recommended)
-
1
Small PCB (radio shack carries them)
-
1
#1 Phillips Head Screwdriver
-
1
spool of wire (doesn’t really matter what gauge, but keep it braided
and around speaker wire in size)
-
2
1µf electrolytic capacitors
-
1
47µf electrolytic capacitor
-
2
22kΩ Resistors
-
1
2N3704 Transistor
-
1
Drill (with a ¼ and/or a 3.5mm drill bit)
For
outputs you have different options:
or
I
opted for choice 2 because it takes up less space and required a little
less wire, but it does require an extra cable (a 3.5>2 RCA Y splitter,
I had one floating around so, that also factored into my decision)
Once
you have these supplies, you can build your circuit. I suggest that
you do so before opening up your Famicom. There are two circuits for
you to build; one for the video and one for the audio. I also
suggest that you keep them on the same board, but on separate sides.
We’ll start by building the audio circuit (it’s easier).
THE AUDIO Ahh,
the audio circuit. Yes, you could go and just tap off the RF board
to get the plain old mono sound, but what fun is that? This circuit
is to make your Famicom sing it’s beautiful song in REAL STEREO.
Yes, real stereo. It outputs the treble/mid on one channel and the
bass/mid on the other and makes a real interesting effect (especially when
amp’d) as opposed to that old mono track you’re used to. Enough
babble, let’s build!
For
the Audio circuit, you’ll need:
or
-
2
1µf capacitors
-
1
Spool of wire
-
2
Female RCA ¼ jacks
-
½
of the PCB
Whichever
audio output you choose, it doesn’t matter. Now to build the
circuit, it’s extremely simple. For now, just connect two 4 inch
pieces of wire to the PCB, each running into the negative lead of the 1µf
capacitor on their own individual line. On the positive side of the
cap, have another piece of 7 inch wire on each go to an individual
lead on the 3.5 connector or just leave them as they are (because of the
way ¼ connectors are, they need to be ready to mount before you can
solder to them). This one is really simple. Now, for the
other half of the circuit.
THE VIDEO Ok,
so this one is going to be a bit tough compared to the last one.
This one will actually involve building a small circuit which works to
amplify the video signal because otherwise, the signal would be too weak
to even make it visible on the TV screen.
For
the Video Circuit, you’ll need:
I
suggest that you start off by soldering the components to the board first.
First put the transistor on, and then place the other parts relative to
the transistor according to the schematic diagram. Then, attach 13
inch wires to the points marked “in” on the diagram. On the spot
marked “+5v”, attach a 4 inch piece of wire. And finally, on the
out, attach a 7 inch wire. Congratulations, you’ve finished the
circuit prep work. Now, it’s time for the dangerous part: Applying
the mod.
PUTTING IT ALL
TOGETHER This
is the part where we finally go inside of the Famicom and install the
circuit that we just built. The first step in doing this is to open
up the Famicom. Unplug everything from your Famicom and remove the
controllers from the holsters. Place the Famicom on a flat and
stable surface upside down so the bottom of it is exposed. Remove
the 6 screws from the bottom with the #1 Phillips head screwdriver and
place them in a safe location.
 Remove
the bottom casing to expose the Famicom’s motherboard and RF unit.
 Now
that the motherboard is exposed, prepare to solder onto the board.
Now, this section is where you can do damage to the Famicom. You are
going to be applying a hot soldering iron directly to the main processor
of the unit. This, if not done quick enough, will do permanent
damage to the Famicom and may even fry the board, making it completely
useless. So, when working on the board, follow these precautions:
-
Only
apply the soldering iron to the board as long as you need to
-
Do
not touch anything under any circumstances. You carry static.
Static causes ESD. ESD can fry sensitive digital
electronics/computers. Don’t touch the board with your
hands (it supports itself, so you don’t have to). This of
course can be avoided by using an ESD strap, but it’s not required
nor do I even suggest wasting your time pulling yours out for this
project.
-
Do
not work with this thing plugged in. You could electrocute
yourself (not likely) or even worse: short out something on the board.
This leads to it getting fried and turns it into a useless pile of
plastic, rubber, metal, and silicone. Don’t work with it
plugged in
-
Don’t
experiment around with it. Sure, it may be fun to take all the
screws out and pull the boards apart and look at all the parts, but
you’re bound to break it. So, no matter how much you wanna,
don’t fool around with the board. It’s got sensitive
electronics that can be fried by touching it.
Follow
those rules, and it’ll be a piece of cake.
The
technique that I use to solder the wires onto solder joints is to apply
enough solder that is needed to said solder joint before hand, and then
heat it up again and apply the wire. It works for me, so I suggest
that you at least give it a try. It solves the problem of holding
the soldering iron, wire, and solder at the same time by applying the
solder beforehand.
Now,
take the “In1” and “In2” wires that is on the video circuit.
Run it parallel with the first controller cable on the right side of the
upside-down famicom. Run them around the screw post and through the hole
in the RF shielding on the RF unit. Right below the RF unit on the
right side, there are 4 solder posts. Solder “In2” into the 2nd
on the right, and solder “In1” to the 1st on the left.
Now,
on the Audio Circuit solder the inputs (doesn’t matter which goes where)
to pins 1 and 2 of the main processor of the Famicom.
 Next,
send the wire labled “+5v” on the video circuit to this pin on the
board. It’s located below the main processor on the lower
right-hand corner of the board. Look at the picture for it’s
location.
 Here’s
the section that’ll make some people squeamish. You will have to
take a drill to your famicom. I personally recommend to drill out
the holes on the front right corner of the unit, but I’ve seen people do
it on the back (you’ll have to extend those cables on the outputs of the
circuits if you plan to do something besides what I did). Here’s a
picture of how I have my jacks mounted.
 Sadly
there’s no real advice I can give you on this. If you screw this
up, you screw up your famicom’s case. You cannot undo this
section, that’s why it’s crucial that you get it right the first time.
Now,
after you drill the holes, on RCAs, solder wire to the ground ring, and
put the ¼ screw on the wire followed by any washers and finally by the
grounding ring. Now feed output cables from the video circuit and
put them out the hole that the video jack is going to go out of and the
audio outs out the audio jack(s) and solder the wire onto the input of the
RCAs. Put the RCA in the hole, and use the screw to jack tight into
the hole. Now take the ground wires, tie them together, tin them,
and then solder them onto the bottom left post on the reset button.
 For
3.5 users, just solder the out wires from the audio circuit to the 2
inputs. Solder a wire to the ground and tin it together with the
video RCA and attach it to the same reset button pin shown above.
Now
just place the board in next to the first controller wire, and close the
baby up.
 Hook
it up, pop in a cartridge, boot it up, and enjoy the fruits of your labor:
great sound and picture quality for your Famicom. |
