原稿 - 英語 - How to make a TV cable for a game gear

1 Construction
Download the Part Layout and Wiring Diagram and print it out (it might be a good idea to trace the wires with coloured pens if you don't have a colour printer). All parts required to build this circuit are available from Jaycar Electronics. Their range isn't very big so hopefully it should be easy for anyone to obtain the parts locally from suppliers with a similar basic range.
I'm aware of two internally different versions of Game Gear. The newer and by far the most common one is the single ASIC (Sega chip) version. The earlier version contains two ASICs and more ram chips. Here are some photos to aid in locating various signals on the board (though the circuit diagram should be sufficient for people who can read it). The power rail (+5v and ground) can be picked off a nearby filter capacitor.
The circuit will be constructed on a piece of matrix style proto-board (not verroboard, though the verro mob probably make it too). It's a phenolic board with a grid of 0.1" holes punched and a single copper pad for each hole on the solder side. To fit all logic ICs on the board we're going to take advantage of the fact that some of the ICs have many pins connected in parallel, and stack them on top of each other. This method saves lots of space and lots of wire. This is important because not only do we save many cents which would have otherwise been wasted on board and wire, but we can also fit the circuit board into the small empty void below the Game Gear's cartridge slot.
Procedure

Here's a step-by-step (ok, more like jump-by-jump) pictorial guide to the construction and installation of the video amplifier/DAC board. This isn't intended to by a 'my first circuit' type of project - good soldering skills are required.

It's much easier to stack and solder the chips before they're on the board. Cut off unrequired outputs, join required inputs and bend out the pins on the 74HC374 first and second stories for the resistors. It's clear in this picture that I've forgotten to bend out the pin 11 clock input. On the left is the double stack of HC74s. Notice that I've connected the inputs of the unused half of the top chip to the inputs of the bottom chip, not +5v as shown on the circuit. I find it's easier this way, it doesn't really matter where they are connected as long as they are not left floating.
2 Chop up the proto-board into a piece 11 holes high and 30 holes wide. Solder the resistors onto the HC374 tower, stuff the rest of the ICs + bypass/filter capacitors on the board and we have something that looks like.
3 Now's the time to wire up the power supply lines to each chip. Once that's done all the logic wiring between the ICs needs to be taken care of. Keep the wires short and neat.
4 The final part, the video amplifier, is added in the middle. This connects to the isolated pads mid right in the picture above. Each input/output each need a wire soldered to it and poked up through an adjacent hole.
5 (Will come later)