1. Introduction
2. Parts List
3. Fabrication
1. Introduction
The DC-PC Serial link cable was designed and realized by Marcus Comstedt, whose homepage is the basis for the material presented below. This page is meant to suppliment the matterial available on his page, and clarify certain issues, and generally make it easier for an average Joe with little experience with electronics to do the best job of building a high-quality, stand-alone link cable that can easily withstand the tortures of daily life. This could easily be considered the complete idiot's guide to cable building.
Please visit http://marcus.mangakai.org/dc/serifc.html and read through (and familiarize yourself with) that document before proceeding with the rest of this suppliment.
2. Parts list
This section differs from Marcus' page in that the design used here is for direct-connection to a PC without the use of a null-modem cable, and was designed without capability to reattach and disconnect the SNK cable.
So, here's the list of parts that you should have:
1. [1] DC-NGPC (Dreamcast to Neo-Geo Pocket) connector (available
from www.lik-sang.com)
2. [1] Maxim MAX3222CPN line driver and voltage converter
IC- available from Maxim (https://shop.maxim-ic.com/) or Arrow Electronics
(http://www.arrow.com)
3. [4] 0.1µFd (microFerrad) capacitors, POLARIZED.
Use only the highest quality audio capacitors for this purpose, voltage
rating of 250V.
4. [1] Female DB9 connector and shielded hood (Radio Shack
#276-1538 and #276-1508 respectively)
5. [2] 16-pin IC sockets
6. [1] spool of 20-gauge stranded hook up wire (Radio Shack
#278-1304 For a 3-pack)
7. [1] Project card, preferably one that's pre-drilled
with a small copper square surrounding each hole. Size shouldn't
matter, as long as it's at least 18x18 holes.
8. [1] Project box, sized appropriately for the PC board.
9. [1] Roll electrical tape
10. Soldering iron, solder (60/40 rosin core-ie NOT ACID
CORE), skill with the afformentioned... knife/wire strippers, diagonal
cutters, pliers, screwdrivers (for assembly).
3. Fabrication.
This isn't as difficult as it may seem. Just make absolutely sure that you have the right components, plenty of hook-up wire, and a nice clean soldering iron.
a) Neo-Geo Pocket Cable.
Use a screwdriver in the obvious spot to open up the casing. Inside you will notice 2 multi-pin connectors as well as some surface-mount electronics, and most importantly, a couple of holes (used to mooch +3.3V to power the Maxim chip). So this is what you do once inside the NGPC cable:
1. Remove CON1's rubber cable dongle from it's notch.
2. Cut the wire that comes from CON1 about 6 inches from the NGPC connector
3. peel back the insulation at least 2 inches using line cutters/whatever
you're used to, and strip each individual colored wire about 1/2 cm and
tin with solder.
4. find the hole to the lef of diode D1 (right in the middle of the
board), and solder a piece of hookup wire to it.
*Make sure the length of the wire is as long as the length of the wires
coming from CON1.
*Make sure to solder on the side of the board opposite the components
5. feed wire from the D1 hole through the recess in the plastic case
alongside the wires from CON1, and reassemble casing- don't place the rubbber
dongle back in the notch to allow the 3.3V wire to exit from the casing.
b) Printed Circuit Card
*Remember to mount things on the side WITHOUT the copper pads (only the leads should appear on the solder side)
1. Near the middle of the card, place the 2 16-pin sockets in-line. Bend pins 1 and 16 of each socket to the side on the solder-side to make sure the socket won't fall off the board while soldering side.
2. Solder the pins of the 2 sockets to the pads on the bottom side of the PCB.
3. On the left-hand side of the PCB, mount the Capacitors. Space them in line at least 4 board spaces apart, with the negative lead of each capacitor on the leftmost side of the board. Once in place, bend the leads of each and solder them to the board.
4. Cut 8 segments of hookup wire long enough to reach from the capacitors to the IC (keep a little longer than absolutely necessary). Tin each end of each wire, and place in holes adjacent to each capacitor lead.
5. Solder the wires from the capacitors to the appropriate holes adjacent to the IC as in Marcus' circuit diagram.
6. Connect the stripped and tinned colored wires to the appropriate places as shown in Marcus' schematic
7. All pins that need to be connected to the female PC serial connector are to be connected as follows- remember, this is to directly connect to the PC without the use of a null modem connector. (Print off Marcus's schematic and re-write the pin numbers accordingly)
Pins 4,5, and 6 remain the same.
Reverse the wires going to pins 2 and 3
Reverse the wires going to pins 7 and 8
*The length of the wires used should be quite long- remember, the connector must reach from your PC to your DC! In this case, 5- 3 foot long wires should work just fine. The wire connecting pins 4 to 6 should be about 3 inches length at most.
*the pin numbers are written on the component side of the D-Sub hood.
8. On the solder side, link all pins together that need to be linked together by bridging with solder or using hook up wire whichever suits the situation...
9. Secure the wires from the NGPC cable to the top of the PC board by wrapping electrical tape around the top of the PC card a couple times.
10. Secure the wires to the Serial cable to the bottom edge of the PC board using the same method mentioned above.
11. Place the IC in the socket (finally!) The lip of the IC should be at the top of the PC card.
*the MAX3222CPN is a CMOS chip, and is fairly sensitive to heat, shock, static etc.. basically everything it would be exposed to if it were mounted first, or mounted without sockets.
12. Use an ohmeter to check the circuit against the schematic, making sure all connections desired are actually connected, and that no solder has bridged in places it shouldn't have. Also check all solder joins for cold solder.
13. Mount in box to your own personal preferrence. Make sure the lid isn't alluminum or something conductive though.
Congratulations! If you've used your head and followed the instructions both here and on Marcus' site, you should have a working cable! I based this document off of my own personal experiences with the project, and my cable actually works, so if you're not getting results, you must not be following instructions ;)
-Infinity_Yak-
modfactor@hotmail.com
www.dmgice.com - your one stop gameboy headquarters