[Xbox rev 1.6 still won’t power on after multiple fixes]

On 7/16/2022 at 10:10 PM, KaosEngineer said:

Is the collector - the pin on the side by itself - of the PNP SMD transistor at location Q7C2 at 3.3Vdc?

There's no reading on either side... I wonder if the motherboard is even receiving any power at all?

[Xbox rev 1.6 still won’t power on after multiple fixes]

@KaosEngineergot any other suggestions? I've been pming with PrehistoricMan and we've tried a few different things. What are your thoughts?

[Xbox rev 1.6 still won’t power on after multiple fixes]

Yes that's what I meant haha, my apologies. I re-did it (I made sure to make the black probe grounded this time) and the reading is still 0.

[Xbox rev 1.6 still won’t power on after multiple fixes]

20 minutes ago, KaosEngineer said:

Okay, now measure the voltage level present at pin 4 of the LPC debug port.  

See: LPC Debug Port - xboxdevwiki for the pinout.

Press the power button. Does the reading go to 0 Vdc?  Next, release the power button. What value does it return to?

 

Do I have to put the prong not being used somewhere else? I tried both prongs in port 4 individually and both came up as 0.

[Xbox rev 1.6 still won’t power on after multiple fixes]

Here’s a pic of the inside:

https://postimg.cc/zV692884

[Xbox rev 1.6 still won’t power on after multiple fixes]

11 minutes ago, KaosEngineer said:

Make sure that the power supply unit's 5Vdc standby voltage is present at the motherboard's power connector.

Use a multimeter set to measure DC Voltages. Set the multimeter to the 20V dc maximum range. Connect the multimeter's red (+) probe to one of the orange wires and its black probe (ground) to one of the black wire metal contacts in the connector body or the metal RF shield.  

Is 5Vdc present?

Yes, 5Vdc is present.

[Xbox rev 1.6 still won’t power on after multiple fixes]

I’ve replaced the capacitors, I’ve checked the power cable, the PSU is good, the transistor has been replaced, it’s a 1.6 motherboard in a 1.6 case, I’m completely dumbfounded. I try to press the power button and get no error lights, no sound from the inside of the xbox, nothing. I see no charred spots anywhere on the inside either, so it doesn’t seem like anything is blown. Can I get some recommendations here? P.S. I’m a bit of a newbie when it comes to part names and locations, so keep that in mind.