Welcome to This Old Modchip
Disclaimer: I am not a member of Team Xecuter nor am I an electrical engineer. What I am presenting here are my conclusions and ideas based on knowledge of the Xbox internals, testing I've done with the switch bank and electronics wisdom I've gained as a hobbyist. I am sharing my theories and observations which may not be 100% accurate. I welcome anyone that has more knowledge on this than I to jump in and correct me if I am wrong. This will both help my own understanding of the X2 chip operation and keep others from using bad instruction.
What I've found with the switch bank is that the different selections are made by grounding three different detection leads. (for lack of a better term) Pins 1 through 3 of the plug on the switch are the leads for Bank 1, Mod Enable and Flash Protect in that order. If these are open, dead circuits then the settings are off. Pin 1 is grounded, the mod will boot from Bank 1; if not it will boot from Bank 2. Pin 2 is grounded, the mod will be enabled and load BIOS from the selected bank; if not it will boot the motherboard's BIOS. (This is the D0 switch) If pin 3 is grounded you will not be able to flash your chip as it will be write protected; if not the chip is free to be flashed. Pin 4 is the common ground for all switches and LEDs. You can use this info and a continuity tester/multimeter to check the function of the switches if you suspect a problem.
All the main switches are Dual Pole Dual Throw, or DPDT. Think of this as having a light switch that in the up position turns on one light, but in the down position turns on another. Now take two of these and link them together, so that when you throw one switch you throw both. The primary use of each switch is to ground the respective detection lead as discussed above. Bank 1, Mod Enable, Flash Protect. The alternate function is to turn on or off LEDs. One interesting thing is the way the Enable/Disable switch is wired. This receives and directs an incoming positive voltage from pin 5. In the disabled position it only provides power to the red side of the Enable/Disable LED. When enabled it provides power to the green side of the Enable/Disable LED, powers the Bank 1 LED and sends power to the Flash Protect and Bank1/Bank2 switches. In this design there is no way the bank selection or flash protection LEDs will ever be lit unless the mod is enabled. Also of note is that this sends a positive voltage back out from the switch bank and to the modchip on pin 6. From quick poking around it appears this only provides power to the blue LED that is on the chip, but it may serve other functions. I don't know if this may replace the function of the Enable detection lead, but this is why the blue LED goes out when you set the switch to Disable. BTW, LEDs (and some similar components I believe) are represented in electronics by a triangle pointing to a line. The triangle points in a positive to negative direction, the only direction voltage will flow through the component. Like she said, traffic there is one way only, mister! The jagged items in line with the LEDs are resistors needed to keep the LEDs from blowing out due to over voltage.
Like the Enable/Disable switch, the Flash Protect switch also will send power to either the green (protected) or red (unprotected) side of an LED. On the Bank1/Bank2 switch it will light the Bank2 LED when in the Bank2 position (well, duh) and does nothing when in the Bank1 position. By the design of the circuit, if the mod is enabled the Bank1 LED will always be on.
Unless! That little SPDT (single pole dual throw) switch that tuns the LEDs on and off? That controls the ground connection for all LEDs except for the Enable/Disable LED. If this is set to off then no LEDs but Enable/Disable will have a complete circuit. This not only includes the LEDs already listed but also the LAN and HDD indicators as well.
Power for the LAN and HDD LEDs come in on pins 7 and 8 respectively. These link right to the green and red wires you (or someone else) soldered to the bottom of your motherboard.
OK, now that we know a bit about how the switch bank works, how can we apply this knowledge?
Scenario 1: While the Xbox is powered off (otherwise this would cause a nasty short) someone manages to knock the switch bank off your Xbox, cuts all the wires and totals the switch bank. So what do you do after you kick his ass? Splice the cable coming from the chip! The cable is known as a rollover cable (not crossover, there's a difference) because the pins are in the exact opposite order on the reverse side. Think of it this way... take your now damaged switch bank and hold it to the mod chip, both with component side up and so that the pins of the plugs were pointing at each other. Pin 1 points to pin 1, pin 2 to pin 2 and so on. BUT if you hold them stacked so that the pins are all pointing in the same direction, this is now reversed. If the pins were pointing towards you component side up, on the switch bank pin 1 would be on the left but on the chip pin 1 would be on the right. Now that you know where pin 1 is on the chip you can match up the functions to the pins on the switch. So if you want your mod to be always on, flash protected and booting off of bank 1 you would want to splice the wires from pins 1, 2, 3 and 4. If you want to boot from bank 2, leave out the pin 1 wire. Want to leave your chip available for flashing? Leave out pin 3. Follow? There may be one problem with this scenario and fix... that positive voltage that goes back to the chip on pin 6. If this does more than just light the LED then the fixes may not work. This is not something I have played around with yet.
Scenario 2: Your X2.3 lite or X2.3B lite switch bank has been damaged, but the wires are still good. What can you do? Get a X2.6CE switch bank! Pins 1 through 5 are exactly the same on the X2.6CE switch bank as on the X2.3 lite and X2.3B lite switch banks. (I cannot confirm any others, these three are the only switches I've had the opportunity to look at.) I've got a similar diagram for the X2.3(B) lite switches in the discontinued modchip forums. The pin spacing on the plugs between the X2.3 and the X2.6CE switches is identical, and the edges of the plug are not wide enough to damage any leftover pins. So long as you have the cable plugged in to pins 1 to 5 only this should work. Check the X2 resellers, I know one of them sells the switch bank separately for about $6USD. Others may also provide this part but not have it listed in the webshop.
Scenario 3: You've got an X2.3 and are bored with the existing switch bank you have. You want the added LAN/HDD/Flash Protect/Bank LEDs as well. Get a X2.6CE switch and (probably more difficult to obtain) 8-pin cable! This is actually where my fuel for this research came from, I'm interested in doing this. Also, someone said it couldn't be done. They obviously were asking for a
Challenge! Here is the trick, which I have not done yet. Intend on keeping the black connector connected to the switch, since I think that helps the overall look of the switches. On this side of the cable, carefully remove the receiver for pin 6. (positive voltage out) You will not be using this output. To remove the receivers you will need to carefully lift the plastic tab portion above the metal bits, and then gently pull the wire and receiver out. This will work best if you have something to hold the plug while you can work with one hand pulling the wire and the other lifting the tab. Use a hobby knife or jeweler's screwdriver, you'll need something small to get at this tab. On the other end of the cable, remove all the receivers from the white plug, same procedure. From your old X2.3 cable remove the receivers from one of the plugs. This empty plug housing will now be attached to the pin 1 through 5 wires coming from the black plug. Remember to keep the order correct, a rollover cable as discussed before. This can be connected to the X2.3 chip. On the LAN (pin 7) and HDD (pin 8) wires, splice on an extension so that you can solder these to the proper points on the bottom of the Xbox motherboard. (See the X2.6/X3 install guides.) I'm looking into finding decent wire to wire plug and receiver components to go in place of the splice, but at this time I do not have any recommendations. Ideally you want to have some way to break the main portion of the cable away from the motherboard. If everything has been wired correctly you will now have your trusty X2.3 chip with the fly X2.6CE switch bank! You'll then be the envy of all your friends, the life of the party and will get the hot chicks for sure! Whoever thought 1337 m0d 5ki11z could go so far?
I hope to have scenario 3 done and working before the end of the year in my box. Just looking for the right plug/socket to go in place of the splice. Anyone have any other ideas/combinations that could be done since I've demystified the switch bank? (really, the pins off the chip too.) Comments welcome as well. PM me if you've got switches from other X2 series chips that you would want to see put into schematic form. I only had X2.3 lite, X2.3B lite (both the same, just different colors) and X2.6CE available for research. Got something else that you can spare?
-Whoopin'
I'll be doing a full 8-conductor cable so that I'll have the 5v sent right back to where the LAN/HDD leads connect and can then wire that up with transistors near the chip, sending the proper voltage back through the cable to the LEDs on the switch bank. Again, I'll update as I continue my projects.
