Hong Kong Famicom

[2A03]

Do the AV mod that's stickied at the top of this board, I wouldn't bother messing around with that aftermarket RF/power board. It will output NTSC video but I believe most PAL TVs support NTSC composite video just fine.

[AvanOsch]

Well, if I connect via the RF connector on a pretty old PAL TV, the video signal is not too bad...
There seems to be no sound though.

But as I get a decent video picture with RF, I'm presuming it's outputting a PAL signal.
(No modifications)

-EDIT-
Or did you mean that the output after doing the AV mod is a NTSC signal?

[2A03]

Or did you mean that the output after doing the AV mod is a NTSC signal?

That's right, since the Famicom still has the NTSC CPU and PPU. Like I said, it would be much better to do the mod as detailed in the Tech Assistance board as I think it'll give you better results than fiddling around with that Makko board. You can tap audio from pin 46 of the cart connector but I got better audio quality by taping the audio from the component labeled FC1 (which I presume is an inductor). I forget exactly which leg to tap from but I believe it was from the point towards the right-hand side, looking at the solder side of the motherboard.

[P]

Famicom still has the NTSC CPU

ROFL Tell me, please where is NTSC output in CPU

2A03 obviously meant PPU.

I haven't seen any attached to a GPM-02 mainboard.

Actually there was another person that posted picture of a GPM-02 board with a Makko mod in this forum recently.

So you couldn't get a decent picture through RF either? With the risk of repeating myself; I also got to try a Makko modded system but I didn't get sound and the picture I got was even worse then what I get from an unmodded Famicom via RF. Maybe they are only good in some Chinese PAL TVs or something.

Do that switch do anything if you flick it? Mine didn't.

[2A03]

Famicom still has the NTSC CPU

ROFL Tell me, please where is NTSC output in CPU

I was referring to the 2A07, I think you could have assumed that easily enough.

component labeled FC1 (which I presume is an inductor).

finally lol
[/quote]
So I tripped over the name of a single component, why does that matter to you so much and why the hell are you using it to poke fun at me? Seriously

[Pemdawg]

Sorry to necrobump, but does anyone have really nice photos of the english decals? I'll be retr0bright-ing my Fami, and that means the old labels are going bye-bye. Since I am doing some mods anyway, I think I'd like to put English decals on it.

[AvanOsch]

So you couldn't get a decent picture through RF either? With the risk of repeating myself; I also got to try a Makko modded system but I didn't get sound and the picture I got was even worse then what I get from an unmodded Famicom via RF. Maybe they are only good in some Chinese PAL TVs or something.

Do that switch do anything if you flick it? Mine didn't.

Wow. Totally missed your post!
I was actually browsing this thread, because of a new "project"...
Sorry about that...

Yes, I did get a decent picture through RF (No sound - This is normal, as 80sFreak pointed out)
Also, the switch makes the frequency change (50/60Hz)
Very funny: 50Hz actually runs slower than 60Hz. You can even hear the speed of the music change!

In the end, I AV Modded this Famicom Picking the video signal off the Makko board.
Turns out, my brother's old TV does support 60Hz, but can't get the colors through NTSC-AV.
(He uses this old thing, because the NES Zapper does not work on flatscreens...)
I actually followed the video traces on the Makko board, and managed to get a decent (Post-PAL-conversion) signal from it.
I used a simple circuit (using a C1815 transistor)
So now this is an AV PAL Famicom.
Nice!
Post Merge: January 19, 2013, 08:16:40 am
Here are some images.
I already returned the console to my brother, so I can't make any pics of the actual mod.
This is where I found the video-out on the makko board.


Using this variable resistor, you can adjust the video brightness.
cool.

[Flying_Phoenix]

Thought I'd just update this thread instead of making a new one.

If anybody cares, I "discovered" that there are at least two hardware revisions of the Hong Kong Famicom HVC-001HKG.

The first one (older) has wires running from the RF board to the mainboard, in order to implement the 50/60Hz mod.
PHOTOS HERE (serial HPH114376, revision of rf board and mainboard 18)

The second one (newer) has no wires; everything is more neatly implemented via small hidden metal connections from the RF board to the mainboard. Basically it's the same mod, but more professionally done, and with much lower risk of damaging the console if opened.
PHOTOS HERE (serial HPH153857, revision of rf board and mainboard 26)

And a small comparison: PHOTOS HERE

You don't need to open your Famicom to find out which mod version you have. Just look through the grating at the bottom of the console; if you can see the green "thing" (a capacitor or whatever) on the left, you've got an older mod, if you can't see anything, you've got a newer mod.

[FAMICOM_87]

Very cool is Hong Kong Famicom to have 50/60MHz option does Hong Kong NES have it too? And how it is even possible with only one X-Tal and Only one chipset (PPU CPU)

[P]

I don't think Honk Kong NES has. The Hong Kong Famicom was supposedly released by Nintendo to compete with the unofficially 50/60 Hz modded Famicoms that people in Hong Kong imported from Japan and modded, since the Hong Kong NES didn't stand a chance against these.

[inabityo]

Hey dude! You seem to be pro'level, I've picked up a Famicom in HK, Japanese casing, all the same, but it has the BN6050i abs I'm not getting any signal out of it. Or at least it is intermittent.

I looks as if the 60/50hrtz switcher is rusted, so I think that's my first stop.

Any other suggestions of what I might be able to try?

I am a noob in this space, but I can solder ok! Any way of soldering components to deliver AV signal?   

The Hong Kong Famicom console is surrounded by mysteries regarding its internal workings. Is it PAL or NTSC? What does the Slow/Normal switch do? How's the compatibility with JP Famicom software? Since HK Famicoms are not easy to come by these questions have been unanswered for a long time.

Today I was looking around on NESdev forums and thanks to its crap forum search function which finds everything except what you were originally searching for, I've arrived to this:

nesdev.parodius.com :: Hong Kong version Famicom clock frequency is 21.3125MHz

A member of that forum got hold of a HK Famicom and was able to take it apart and see what made it tick and how it did it.

I finally got a Hong Kong version Famicom recently. That uses NTSC CPU and PPU chips, but there is an NTSC-to-PAL conversion chip in the power/modulator section. (Nintendo patented the conversion technique used by this, the patent is interesting reading.) That chip converts the colour encoding, but can also halt the PPU in order to get a 50Hz picture. There is a 50/60Hz switch on the back of the console. Strangely, on the old PAL TV I tested the console with, the 60Hz PAL picture is fine but the 50Hz picture appears in black and white.

Anyway. The crystal frequency in the Hong Kong Famicom is 21.3125MHz (vs 21.47727 for a normal NTSC Famicom). The reason for the difference is probably so the horizontal scan rate is closer to the 15.625kHz PAL standard. Maybe some PAL TVs were not tolerant of variations???

The result is that (in full-speed mode) the Hong Kong Famicom has a frame rate of about 59.5 Hz.

The console main board ID is HVC-CPU-NPC-26-01
A label on the power/modulator shielding reads HVC-HKG-26
The NTSC-to-PAL chip has 20 pins and is marked N NPC26

Thanks to his findings we can finally reveal the truth about the HK Famicom!

So, the HK Famicom is a standard Japanese NTSC Famicom sporting a 2A03 CPU and a 2C02 PPU (and thus it's fully compatible with JP Famicom software - in essence it's a NTSC model) but it has been fitted with a Nintendo made NTSC to PAL transcoder circuit to convert the NTSC color signal into a PAL one for HK TVs.

Additional to the NTSC to PAL transcoding, the circuit is able to produce a 50 Hz video signal by "freezing" the PPU chip during operation and thus reduce its effective frame rate. So this is what the Slow/Normal switch does. It's a 50/60 Hz switch, albeit a very complicated one.

In the Normal position, it allows the PPU to function as usual, making the system output PAL60 video (this means 60 Hz video with PAL color encoding, which violates the PAL standard but can be displayed by some TVs). In the Slow position, the PPU gets halted at defined intervals to produce 50 Hz video, and thus a "true" PAL video output.

On the other hand, a PAL NES uses a completely different CPU and PPU (2A07 and 2C07) in addition to a different crystal oscillator. It runs at a lower CPU speed, generates a perfect PAL signal right from its PPU and thus needs modified software. The HK Famicom is a NTSC Famicom which has been kludged by Nintendo themselves to produce pseudo-PAL video output. It's compatible with NTSC games and incompatible with PAL games.

Further down the thread, another mystery is revealed. I remember seeing a Famicom like this one here in FW at some point in time:




We were all puzzled by the combination of an official Famicom motherboard and a seemingly unlicensed RF modulator board. This RF modulator board contains a chip in the middle labeled MK5060 and there's a multitude of wires running from it into the Famicom motherboard. The PCB is labeled Makko Toys, Ltd. Nobody at the time had a clear answer for this.

It turns out that this unlicensed RF modulator board does the same thing as the HK Famicom's video transcoder. The MK5060 chip converts the NTSC video output of the original Famicom into PAL video and provides the same PPU freezing facilities to enable 50 Hz video output (this explains the multitude of wires running from the chip into the motherboard). In this case the TV/GAME switch would work as a 50/60 Hz switch using the same technique as the HK Famicom. The rest of it is a plain vanilla Power/RF Modulator board which is probably tuned into European/Asian channel frequencies.

What could have been the uses for this? I presume that this board was used by unlicensed outfits to import Famicom consoles into PAL territories, especially China, Hong Kong, Taiwan, etc. By fitting one of these boards into a NTSC Famicom, it effectively turns into a PAL one which is able to run Japanese games.

It opens up the question: Which method came first? Nintendo's or Makko Toys'? Did Nintendo create the HK Famicom as an answer to the proliferation of PAL-modded Famicom consoles in places like Hong Kong? Or was it the other way around? Both scenarios seem pretty plausible to me.