Xbox One - No Power

[spleenharvester]

Hi all,

Interesting Xbox One problem here (older Phat version).

When it first came to me, it would usually turn on then straight off. Then it turned on and worked fine, with a grinding fan.

Now it doesn't turn on at all (no chime). When the PSU is plugged in, it goes white; there's a buzzing noise from the CPU Vreg area for about 10 seconds; then it powers straight down.

I notice now that the fan seems to be dead (12V at the connector but only 1/4 spin). Would this cause this kind of behaviour?

I've tested with a different power supply, same shit.

Cheers

[spleenharvester]

Re: Xbox One - No Power

Also worth noting as well that I've tried applying light pressure to the SB and APU, it doesn't change the behaviour.

[stj]

Re: Xbox One - No Power

is the fan stiff?
if it is, fix it, the system may be watching the rotation for safety.
[disclaimer - i never worked on a one, and only a few 360's - but i'm a master on the original boxes)

[spleenharvester]

Re: Xbox One - No Power

is the fan stiff?
if it is, fix it, the system may be watching the rotation for safety.
[disclaimer - i never worked on a one, and only a few 360's - but i'm a master on the original boxes)

Okay so it turns out I was wrong before - the 10s on/off thing when the PSU is first plugged in seems to be normal.

When the eject button is pressed it now powers on, but hard shuts down the second it hits dashboard. The power button doesn't seem to be working. The fan does spin during this, it just doesn't sound very happy.

[stj]

Re: Xbox One - No Power

well it could be the fan, or the power to the fan.
you still didnt answer the question - if you flick the blades - does it spin freely?

[spleenharvester]

Re: Xbox One - No Power

well it could be the fan, or the power to the fan.
you still didnt answer the question - if you flick the blades - does it spin freely?

Yes it does spin freely. I'm going to try a different fan now.

[spleenharvester]

Re: Xbox One - No Power

Tried different fan, still shutting down. Tried different XB1 HDD, sits at loading screen forever. With the old HDD, it sometimes shuts down even before dashboard.

Power seems to be completely stable with no HDD plugged in.

[spleenharvester]

Re: Xbox One - No Power

Okay so I completely wiped the HDD and rebuilt it with OSU1. Seemed promising, stayed on during setup, then died as soon as it hit dashboard again. I assume this is going to be some sort of weird APU thing?

[stj]

Re: Xbox One - No Power

psu caps??

[spleenharvester]

Re: Xbox One - No Power

psu caps??

PSU is known good from my other console. Exhibits same behaviour with both PSUs I have.

EDIT: It just stayed on the dashboard for maybe 10 seconds longer than it usually would, let me move around a bit before dying in the same way.

[spleenharvester]

Re: Xbox One - No Power

Okay I'm fairly sure this is an APU or RAM chip fault now as I've noticed the display sometimes artifacts for a split second before losing power. Ah well, was worth a shot.

[RepairMonkey]

Re: Xbox One - No Power

Disclaimer - I'm new to this and learning.

I'd be curious to monitor the CPUCORE, GPUCORE, MEMCORE and NBCORE core voltages with an oscilloscope or decent multimeter. Going from the symptomatic behavior of PCs (this is essentially a laptop) I'd expect that the Xbox would freeze / reboot and provide an error code if there was an APU / GPU / memory error rather than shutdown (unless over temp - but it would shutdown and on restart there's still an error message - AFAIK).

[spleenharvester]

Re: Xbox One - No Power

Disclaimer - I'm new to this and learning.

I'd be curious to monitor the CPUCORE, GPUCORE, MEMCORE and NBCORE core voltages with an oscilloscope or decent multimeter. Going from the symptomatic behavior of PCs (this is essentially a laptop) I'd expect that the Xbox would freeze / reboot and provide an error code if there was an APU / GPU / memory error rather than shutdown (unless over temp - but it would shutdown and on restart there's still an error message - AFAIK).

As it happens I work at a company that does board-level repair on PS4 motherboards - often random power shut downs are caused by APU issues in these machines, and since both are Jaguar-based I wouldn't be surprised if the same happens in the XB1 too. The way that it shuts down at dash reminds me of failing PC graphics cards, that appear fine but die as soon as a driver is loaded.

I'd be tempted to look at the core voltages you described, but tbh, I'm just not good enough at board-level repair to understand what's happening!