my modded original xbox wont turn on...

Interesting, mine was doing the same thing so I registered to post how to fix it... My xbox was powering up but I wouldn't see anything on the TV, I'd just hear the fans going, but no picture.

I changed the setting in the chip # 2 to ON and now everything works. wow. :shrug:

 

The XBOX SMC (System Management Controller or the "PIC" chip) is programmed to do that in case the main CPU spits an kernel panic or is unable to start.

It will power on, detect the problem, power off then power on again. If it does not boot, the SMC will cause the two leds to blink signaling that there is a fault condition.

Things that might cause the issue:

Corrupted flashrom (bad bios)
Corrupted EEPROM (bad eeprom or missing data in it)

Hardware faults related to modding (cut traces that could prevent the system from acessing the flash chip with the bios).

The system could be modded to boot from LPC bus (NOR FLASH line D0 connected to GND) and there's nothing connected at the LPC bus or whatever is there is faulty ...

Etc etc etc ... :shrug:

As per ODD BEHAVIOR on the power and eject buttons it's very likely that the console is being victim of a leaking SUPER CAPACITOR (the capacitor that keeps the real time clock running when the system is disconnected from the wall plug) and traces were corroded.

Be aware that the leaking SUPER CAPACITOR was the real cause of the XBOX fires back in 2003 and the power cables fiasco was smoke screen strategy for damage control.

If you like your classic XBOX and want it to be healthy for the years to come, open it up and TORE the damn SUPERCAP out.