Hong Kong Famicom

[133MHz]

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.

[b1aCkDeA7h]

Haven't a clue about what came first but I do have one of these elusive famicoms. No box though.

Actually, I'm trying to get rid of it but nobody on DigitalPress seems interested.

Anyone here want this thing?

[L___E___T]

How much are we talking minus shipping?  I might get one just because my AV famicom buzzes on my PAL TV.

[b1aCkDeA7h]

How much are we talking minus shipping?  I might get one just because my AV famicom buzzes on my PAL TV.

I'm not looking to make any money off of it, so I'm only asking $25 without shipping (the price I paid for it).

Almost forgot to mention this but its important. I don't have an AC adapter or an RF cable for it. I tested it with the RF cable from my NES and the AC adapter from my A/V Famicom. Glorious black and white with no sound.

[L___E___T]

Great price but the shipping could be killer.  I wouldn't get an NTSC to PAL convertor, it's not the NTSC signal it's the machine itself.  My other NTSC consoles work fine but thanks for highlighting the idea.

If it's around in a week I may come back to you!

[b1aCkDeA7h]

Great price but the shipping could be killer.  I wouldn't get an NTSC to PAL convertor, it's not the NTSC signal it's the machine itself.  My other NTSC consoles work fine but thanks for highlighting the idea.

If it's around in a week I may come back to you!

Nobody's expressed interest thus far on the DigitPress forums in that so I think you're pretty safe. Even if it's worldwide shipping, I'm pretty sure I can take care of customs and keep the costs down with good old flat rate from the USPS.

[NintendoKing]

i like the front label on the HK Famicom, also the fact it works on both PAL and NTSC makes it grand to own.

I personally would really like to see that.

[b1aCkDeA7h]

i like the front label on the HK Famicom, also the fact it works on both PAL and NTSC makes it grand to own.

I personally would really like to see that.

It is rather interesting. All of the labels that are Japanese on a standard Famicom are in English. I suppose all of this can trace back to the fact that Hong Kong was a British Territory for quite some time. It certainly explains the use of the PAL video format.

[Famicom Beginner]

hi guys im a noob and have bought a famicom HK version i was just wondering if you know if a japanese disk system would work on the HK famicom please help me !! thanks   

[shoggoth80]

There is another thread detailing the HK Famicom. It seems like the video signal is converted to PAL post-motherboard. This means that it should be compatible with Japanese Famicom software. If this is the case, I do not see why Disk System stuff should be a problem.  Unless the Disk System has its own video and audio outs (I have a Sharp Twin, so I do not know what the standalone disk unit's cables/connections are). If I am wrong, someone will correct my deductions.

[ericj]

The FDS should work fine with a HK Famicom. I don't think there was a HK Disk System (but I could be wrong), but know for sure that a lot of FDS pirate disks come from Hong Kong and they work fine on a Jap. FDS & Famicom setup.

[Famicom Beginner]

thanks for the fast reply guys  thats helped me out quite a lot, £50 is a lot spend if it aint gonna work lol

if either of you have got any more info that would be great thanks again 

[133MHz]

Welcome! Where are you from? I presume you're European since you're getting a HK Famicom.

[Famicom Beginner]

yeah lol i am from UK i received the famicom disk system and it worked fine with famicom grand prix first time so thanks for the sound advice, but after i turned it off and went to play it again it just comes up with err 27 any clues guys ??

[ericj]

Try cleaning the disk and also the head in the disk system with q-tips & a bit of isopropyl alcohol.