Hello,
Have an Xbox One S here that has a short on the 12V power rail. There is no power, beep, or partial fan spin when connecting power cable.
After diagnosing with thermal camera, Q9F1 MOSFET (NTTFS4C50N) is getting hot. When I remove this MOSFET, the short on the 12V rail disappears.
I first replaced Q9F1 with one from a donor board and then partially reassembled the Xbox to test. When I plugged the power cord in, I got a partial fan spin and I thought I had fixed it, but unfortunately, the Xbox still did not power on. So I then disassembled the Xbox again and found that my newly replaced Q9F1 had blown again. So this time, I used another donor board and replaced Q9F1, Q9F2, and U9F1 which both of the MOSFETs are connected to. I checked to make sure the short on the 12V rail was gone and it was until I connected the Xbox back to power and it blew Q9F1 again. Something keeps blowing Q9F1 as soon as power is connected.
Upon further probing, I have found a short on Pin 1 of C9F1 which is V_VTTB. I am reading 0.013V in diode mode and a working Xbox has a diode reading of 0.305V.
The only components on that entire V_VTTB line is a whole bunch of resistors and a few capacitors so I removed ALL of the capacitors on that line and it's still shorted to ground. What does that mean? Internal short? One of the RAM chips shorted since it's on a memory line?
Hoping someone could help. Thank you.
Have an Xbox One S here that has a short on the 12V power rail. There is no power, beep, or partial fan spin when connecting power cable.
After diagnosing with thermal camera, Q9F1 MOSFET (NTTFS4C50N) is getting hot. When I remove this MOSFET, the short on the 12V rail disappears.
I first replaced Q9F1 with one from a donor board and then partially reassembled the Xbox to test. When I plugged the power cord in, I got a partial fan spin and I thought I had fixed it, but unfortunately, the Xbox still did not power on. So I then disassembled the Xbox again and found that my newly replaced Q9F1 had blown again. So this time, I used another donor board and replaced Q9F1, Q9F2, and U9F1 which both of the MOSFETs are connected to. I checked to make sure the short on the 12V rail was gone and it was until I connected the Xbox back to power and it blew Q9F1 again. Something keeps blowing Q9F1 as soon as power is connected.
Upon further probing, I have found a short on Pin 1 of C9F1 which is V_VTTB. I am reading 0.013V in diode mode and a working Xbox has a diode reading of 0.305V.
The only components on that entire V_VTTB line is a whole bunch of resistors and a few capacitors so I removed ALL of the capacitors on that line and it's still shorted to ground. What does that mean? Internal short? One of the RAM chips shorted since it's on a memory line?
Hoping someone could help. Thank you.
