Composite Modding the Pyuuta Jr. (and Mk II)

Last modify 1 January 2007.

Thanks to Chris Collet who modified his own Jr., and sent me how he did it.

The fact that the Pyuuta Jr. is RF-only is a serious pain to us in the United States because even though Japan uses NTSC, they use different channel frequencies. Fortunately, it is not at all difficult even for someone like me who is all thumbs with a soldering iron to tap the RF modulator and get a composite signal out. You can then run this into anything that accepts composite video, like a video capture board, your current TV/VCR or an old-school monitor like a Commodore 1702.

It is expected that you have some experience with soldering components; the Pyuuta Jr. is not surface-mount, so this is actually very straightforward even for novices. This should also work for the Pyuuta Mk II, although I would verify that the RF modulator is wired the same on your unit. It appears to be so on mine, but I have not tried it and can't guarantee it.


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[Getting started.]
Getting started. For the jacks, I went to the local Rat Shock Radio Shack and bought a headphone-2x RCA jack Y-adapter (PN# 42-2546). You could do this with plugs if you like, but obviously you'd better make sure you have enough length. For the jacks, a few inches should be adequate. I snipped them both right at where they enter the sleeve for the headphone plug.

[Isolating the RF modulator.]
Crack the unit open by undoing the screws and separate the halves (the front console half is at the bottom facing me) so as not to pull on the ribbon cables. If you don't understand how to open the unit properly, read the disassembly portion of the Jr. page. The RF modulator is taped, at least on mine, to a slot facing the rear ports. Remove the tape and bend it back to the front in this position, solder pads up.

[RF modulator wiring.]
There are four wires going into the modulator, three marked. V (red) is the video input, A (white) is the audio, and B (orange) is the power to the modulator. Wire colours may vary, so do this based on labeling if you can. Chris' unit has a G for the earth/ground (green) but this isn't on mine. We will be connecting the video jack to V and G, and the audio jack to A and G. Don't hook up anything to B.

The really reckless could conceivably just snip the wires right here and solder directly to them, but the solder pads on the RF modulator are so huge that it's better to solder to them instead and leave the modulator intact (and you could still use it with a TV this way if you move to Japan).

[Testing with alligator clips.]
The Paranoia is strong in this one. After clipping and stripping the jack leads, I hooked up the jacks to the modulator solder pads with alligator clips just to make sure I had the right ones and to confirm which jack lead was ground. I suggest you do the same. The red clip was supposed to be on the rightmost pad in this orientation but seems to have popped off for this picture.

Keep away from the power supply while the unit is operating and the case is open, of course.

The video did work, btw -- more about the quality of the picture in a moment.

To make it easy on myself, I used the same colour jack for the same colour wire (so red for video and white for audio).

[Completed soldering.]
After that, get out your soldering iron. On my unit, the factory had gone a little overboard with lacquer and you may have to burn through that some to get it to stick. Don't breathe the smoke. (Not enough to make it non-conductive but just enough to be annoying.)

In this orientation, the ground/earth is the furthest pad on the left, the audio pad is fourth from the left, and the video pad is the furthest pad on the right. I wrapped the ground leads, which had no separate shield in this jacks, to prevent the very real risk of shorting something. Test your connections again.

[Securing the leads.]
Run the cables out the vacated hole in the back -- they'll fit, and no case cutting is required. Note that the tension is such that yanking on the cables will yank on the solder joins, so I taped everything down inside to put the stress point on the tape instead. This also holds the RF modulator down so it doesn't clank around either.

[Completed modification.]
Finally, put the halves back together (watch out for the RF modulator's original tape sticking out) and close it up with the screws. Looks very nice. I later labeled the jacks with a Sharpie due to the non-standard colour choice.

[Video quality.]

An uncorrected screenshot taken off my quad Power Mac G5, using a Canopus ADVC-300 FireWire capture device. There is actually fairly low chroma noise for a non-separated video connection, so the picture is nice and sharp considering the source, but the overall brightness is a bit dim. It doesn't seem to have much problem on my Commodore 1702 monitor, though, so this might be something about the ADVC-300. You might play with your video settings for the best picture.

Overall, I'm happy with it, and this allowed me to fix the crap screenshots I'd had up of the Pyuuta Jr. from before. A little bit of gamma adjustment in Graphic Converter, and the new screenshots came out nicely. So all's well.

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