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[Chancer]

First thing to do is to connect Xbox D0 to a ground point on the mother board.
If the original bios still boots, unplug the chip from its header and boot up again. The machine should FRAG. If it doesn't then the D0 point connection is the problem.
 If it does FRAG then connect a straight link between BT and Pin 9 (point G) on the chip. Do not connect a wire to the BT point on the Xbox at this point.
Boot the box and it should boot with the chip enabled. If it doesn't the chip has died.
If it does the problem is the original BT wiring. Take of any links on the chip and re-wire BT direct to the correct point on the Xbox

[Joshua Wood]

With the xbox d0 directly to ground, the xbox frags with or without the chip on the pin header, suggesting a faulty chip. I even wired BT direct to pin 9 (G) and still it frags, as was expected.

The only other thing left to try, although it's looking like the chip, is that I have my own bank select switch. Is there a way I can hard wire a bank on? So I'd need to go from pin 2 to somewhere I would guess....? Just in case something in my switch circuit has failed. Some of it (where the original duox2 switch was) has been hot glued over, so it's hard to get into to check anything here.

Thanks.

[Joshua Wood]

Ok, I brought a new duox2 chip. With BT soldered direct to pin 9 (chip always on) and xbox underside d0 directly soldered to ground, it still frags. This suggests my original chip might be ok. I don't get a flashing red light on the original or new chip.

Any suggestions as to what to check out next?

[Chancer]

The chip is obviously now enabling and was not at first, so now you can rule out D0 (Providing it still boots MS Bios with D0 disconnected) and BT and the chip.
The only thing left is the soldering of the pinheader and rebuild.
I would reflow the solder to all the rebuild and pinheader connections

[StrictPuppet]

QUOTE(Joshua Wood @ Dec 19 2007, 12:29 AM)

Using a multimeter and with the xbox on, the top LPC pins measured from the top of the chip read:
1 - 1.6V
6 - 5.25V
7 - 3V
8 - 3V
9 - 0.8V
10 - 3V
11 - 3V

All others read 0V. BT reads 0.5V, d0 reads 0V.

Assuming you are using the conventional pin numbering, you should have 3.3v on pin 9

[Chancer]

With the box powered on there should be 3v3 on Pin 9. If it is missing the chip will not work.

[Chancer]

Just follow the print (trace) back from the LPC pin and jumper a wire from the next solder point back
It should be fairly easy with a good magnifier

[StrictPuppet]

You should also have 3.3v on pin 15 of the LPC(unused).  If you dont, you have a greater problem.  If you do, you should be able to place a jumper on the bottom side from pin 9 to 15.  9 and 15 are both vcc and not data points.

[Joshua Wood]

Excellent. Pin 15 still had 3.3V and bridging it to pin 9 worked perfectly. My mod chip is now working again. Much thanks to all for the help.