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Xbox One S, progettata da Microsoft Corporation, è stata rilasciata ad agosto 2016. Xbox One S è una riprogettazione di Xbox One.

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PSU 11.94V, White Light, Start Beep, Then Turn Off Beep

Update: I have advice from the element14 forums to replace all of the MOSFETs at once. I have yet to try this. I have some light experience using the hot air rework station and Gough Lui gave me some very good advice on how to improve my technique.

Does anyone else have some advice in this regard?

First disassembly and diagnosis:

Tried to swap the MOSFETs:


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I have an XBOX ONE S that I bought as “for parts” on eBay and the owner says it was kept in a clean house, etc. It is indeed clean inside. No signs of water damage.

The PSU is also fine. The APU had a TON of thermal grease all over the surface mount capacitors. I didn’t remove that yet but I did re-apply some arctic silver and I used a more reasonable amount.

The symptom I see:

Console when plugged in does a few quick pulses to the APU fan. Is it trying to init?

Console when eject is pressed makes the eject sound, then the shutdown sound immediately after.

Console when power is pressed makes startup beep and then shutdown beep immediately after.

I don’t know what kind of issue I’m getting yet. Is there a JTAG interface or some way to do further diagnosis on this thing?

11.94V sounds perfectly fine for a 12V rail. Should I simpy try plugging a PC power supply into the motherboard to see if it will boot?

Any links or info on diagnosis would be appreciated.

Thanks in advance!


Photos of my motherboard:

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I need to find a place to buy a handful of both of these MOSFETs.

4C50 and 4C55N

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Aha! In the image you can see the CPU filter capacitor is registering just 1 ohm! The others are pretty low too but I bet if I remove that one it’ll at least boot. I have a server motherboard with a broken socket that I can steal capacitors from. Might replace the whole row if necessary.


Looks like I was wrong. That capacitor I removed still offers up almost exactly the uf value on the tin. So that was another dead end. Hmm... One weird thing, all of the test points register 60Hz but not 110V. So thankfully the PSU isn't pushing wall socket voltage through. But that frequency is weird. My multimeter needs a charge though so I'll measure that again after it has.

The entire power area for the APU offers almost no resistance to the ground plane which is worrying. Again, need to charge that multimeter and re-check.


Power on with no heatsink, the processor doesn't even warm to the touch. CPU, GPU, and other test points around the board pulse to 1-2V and then turn off fast.

Can't help but think it's related to the very low impedance between ground and positive on the V rails for the CPU/GPU. Is that normal?

USB port is charging the multimeter :)

So that 5V rail from the southbridge is working.

Lots of 12V test points are consistently 12V (11.94V)


Your bot is broken, iFixit. My last comment above this one was not spam. It was a further explanation of a technical issue that might help someone else in the community.


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Soluzione Prescelta

Did you ever get to the back of the problem? I have the exact same issue. Do I need to reball the APU? Thanks

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MOSFET is toshiba TPN8R903NL IC is TPCA8A11

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I already figured that part out but thanks for this!

Yeah I think the issue still might be the APU but since I mucked around with he power circuitry I have made things worse. Ah well :shrug:

I can try again some day to fix that part and see if I can try to reball the APU again.


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I saw your question “If you have a multimeter could you please test the test points around the board and give me a list of a voltages?”did you endup getting it? If so could you share?

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All of my testing results are here on the Element14 forums. I've given up on it for now. It's a pile of parts in a container for now. I might be able to test again but I actually repurposed the 12V PSU for something else, so I'd have to put the original cord back on or provide it with 12V some other way.


This is not the One S but someone posted this test points listing elsewhere:


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Lilithe Lotor sarà eternamente grato.
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