ASSEMBLING THE SIO2PC INTERFACE Thanks for deciding to build it yourself! A diagram of the circuit board is enclosed. It shows the top (component) side of the board. The other side is the "foil" side. In the drawing there appears to be no space between adjacent copper pads from the IC pins. Of course, there really is, my printer just isn't accurate enough. When in doubt, check the layout against the schematic diagram. Please read through all before starting. Since this board is symmetrical, it's easy to get confused when you turn it over, and forget that you're looking at a mirror image of the top. I suggest marking "TOP" on one end, and marking IC pin #'s 1,8,9,& 16 on the board, both sides. The first work item is to solder in the 16 pin IC socket. Orient the pin 1 identifier notch correctly. You may choose to put it more near the center of the board. Now, you should solder in the jumper wires. They are shown as heavy lines. But note that the leads from the 4 electrolytic capacitors are also shown as heavy lines. In places where no other wire could contact a jumper, I use bare wire, because I don't like stripping insulation. Several jumpers are just extensions of the capacitor leads and you can usually make them reach with no jumper added. Note that the foils really are close together and it's easy to create solder bridges. Use good light. I also inspect my work with a magnifying glass. (I started after a solder bridge gave me fits troubleshooting.) In cases where the board layout is hard to follow, use the schematic diagram to confirm connections. Now, install the capacitors. On the electrolytics, the minus lead is marked, and it is the shorter one. Yes, the places where the (+) lead of an electrolytic goes to ground and where the (-) lead goes to the +5 volt line are both correct! Now, It's time to plug the IC into its socket. There is a dimple or notch marking pin 1. Be sure to get pin 1 in the right place. You usually must bend the pins in a bit to get them aligned for insertion. After installation, inspect closely for pins which may have bent under instead of inserting. Now, wire the two connector cables to the board. FIRST PULL THEM THROUGH THE GROMMETS IN THE BOX. The Atari cable may have a larger grommet. You should grease the cable with some Vaseline, or friction may pull the grommet out. Note that the board is going to go into the box component side down, foil side almost flush with the top. You also need to wire the PC's DB-9 connector per the pin #'s given and the diagram shown looking at the end the cable solders to. The pin numbers are on the connector too, if you have real good eyes. You may want to dress the wires to the appropriate length based on where they have to go on the board. Note that the green from the Atari has to reach almost all the way to the other end. Cut back the extra wires in the Atari cable. Note that on the PC cable, wire colors may vary. Cable: Wire: To: Atari: Violet IC-10 " Shield PC cable shield " Black GND " Blue +5V " Orange junction of 4.7K* & diode " Green IC-11 PC Shield Atari cable shield " Green IC-7 " Red GND " White IC-13 " Black IC-14 TESTING: Plug the interface into the Atari (not the PC, yet) as the only peripheral, and turn on the Atari. If you don't get the blue screen and "memo pad mode" message, turn if off and troubleshoot. If all is OK you might want to check voltages coming out of the DB-9 connector. Using pin 5 as common: Pin 9 = 9v Pin 3 = ~0v Pin 2 = -9.4 Note that pin 3 is an input and its reading has little meaning. Also, plus or minus a couple of volts on 9 and 2 is probably OK. Now, go to your operating instructions and give it a try. If all is well, put it in the box and put on the lid. I suggest a turn or two of electrical tape around the ends of the cables to relieve strain and resist pull-out. If you have trouble, you can check the 232's charge converter output: pin 2 should be about 10 volts to ground, and pin 6 at about -10 volts to ground. If this isn't the case, check the polarity of your capacitors. A leaky capacitor could also be the culprit, or the ever popular "solder bridge." PARTS LIST FOR SIO2PC KIT _____ 1 - BOX, /w LID, SCREWS _____ 4 - 22 uF ELECTROLYTIC CAPACITORS, 25 VOLT _____ 1 - 0.1 uF DISK OR MONO* CAPACITOR _____ 1 - INTEGRATED CIRCUIT, I.C. (ICL-232 OR MAX-232) _____ 1 - SIO CABLE WITH CONNECTOR _____ 1 - 4 CONDUCTOR CABLE, SHIELDED _____ 1 - DB9 OR DB 25 CONNECTOR, AS RQ'D FOR YOUR PC _____ 1 - CONNECTOR HOOD _____ 1 - CIRCUIT BOARD, RADIO SHACK 276-150 _____ 6" BARE WIRE _____ 6" INSULATED WIRE _____ 1 - 16 PIN IC SOCKET _____ 1 - ASSEMBLY INSTRUCTIONS _____ 1 - CIRCUIT BOARD LAYOUT _____ 1 - SCHEMATIC DIAGRAM _____ 1 - 4.7K - OHM RESISTOR _____ 1 - DIODE - BYV10-30 or 1N5817 * The MONO type capacitor looks like a resistor or diode & should be marked 0.1 or 104. Please check items received against this list.