Visio serial cable schematic (.vsd)
Because there are at least 10 major PS2 mainboard revsions, and I built my cable on a V4, there
might a few differences in the location of the points you'll need to solder. The main one is the
pad for +3.3V. Refer to the installation diagrams of any recent modchip (Messiah, DMS, whatever) for your
PS2 version, and you should be able to find the right +3.3V pad to use. Also, my pictures of the serial pads beneath
the EE might differ slightly from what you see on your mainboard. As far as I know, the serial port pads exist
on all PS2s, so as long as you find the right set of pads you should be fine.
I used the following color scheme for the wires on the PS2 mainboard and the interface circuit:
- Red - +3.3V
- Black - GND
- White - EE core voltage (Vcore)
- Blue - EE_TXD / PC_TXD
- Green - EE_RXD / PC_RXD
First, open your PS2 and get to the mainboard. Again, use the installation instructions of a modchip to
figure out how to take apart your PS2. You should be facing the side of the mainboard opposite the EE, with
the A/V and optical connectors closest to you.
Start by connecting GND, then locate your board's pad for +3.3V and connect it.
If you look at the right side of the bottom of the EE, you should see 4 square-shaped pads. You should also
see a gap between the first pad and the bottom three. This is the EE's serial port.
The top pad is EE_TXD. Make note of the via (the tiny circle) sitting by itself immediately above EE_TXD. That's the EE_RXD pin.
The third and fourth pads are RTS and CTS, but we won't be using those for our cable.
Carefully - VERY CAREFULLY - connect the wire to the EE_RXD via. The best thing to do is to tin the wire,
and when soldering allow the solder to flow down the wire onto the via, to avoid touching the soldering iron
to the via. Coat the via with flux to make sure it gets wet. Take your time because if that via falls into the
depths of the board, your PS2 won't be able to receive data.
Connect EE_TXD to its pad.
The last spot is the EE core voltage (labeled Vcore in the schematic). There should be a large black capacitor sitting
right next to the second pad, connect Vcore to the silver end.
Now that you have all of the wires connected, tape them down and run them through the side of the board that has
a notch for the power supply's power switch. The PS2 has two small screw holes on opposite ends of the back, and I ran
my wires through the hole that sits in between the A/V connector and optical connector.
Reassemble the PS2, making sure to thread the wires through the screw hole so they stick out of the rear of the PS2.
If you got ahold of a 5-pin plastic header, attach the wires to the female end.
Building the interface circuit should be straightforward, just use the schematic at the top of this page. The board
I listed in the Parts List has more than enough room for the MAX chip and spots to attach the 5-pin header and DB9 cable. In
the schematic, PC_RXD is pin 2 of the DB9 header, and PC_TXD is pin 3. Also be sure to connect GND (pin 5) of the DB9 header to
GND on the circuit. Here's the complete list of connections:
- Capacitor across C1+ and C1-
- Capacitor across C2+ and C2-
- Capacitor across V+ and GND
- Capacitor across V- and GND
- EE_TXD to TIN1
- EE_RXD to ROUT1
- PC_TXD to RIN1
- PC_RXD to TOUT1
- Vcore to VL
- +3.3V to SHDN, RENABLE, TXENABLE, and Vcc
- Capacitor across Vcc and GND
- Pin 5 of DB9 (GND) to GND