This is definitely a noob question, I'm not an engineer but as far as my knowledge goes, the power supply on a phone would be its battery. However, my Nexus One stopped turning on recently, the battery charges fine as the LED indicator shows, but when I try to turn it on I get nothing. This is the result of me taking the phone apart and trying to clean the contacts of the sim slot as it wasn't recognizing sim cards, and after putting it back together I can't seem to turn it on anymore.

I then took the phone to a repair center and the guy told me the power supply is bad that he would have to replace it, the battery is fine but its not getting power to the device. So my question is, what is this power supply he speaks of? The battery is fine, and hes obviously not talking about the power adapter... and what could cause this power supply to fail? I followed the directions here to take apart

2 Answers 2


It's quite possible you accidentally shorted out a circuit or otherwise damaged some part (ribbon cable, connector, etc.) while disassembling or re-assembling your phone. The "power supply" line the tech fed you is probably just that, something they said to avoid going into too much technical detail.

It's unlikely that they will bother with figuring out which exact part is fried, and will probably opt for replacing the phone's whole main board instead. Be mindful of the price they quote you, because these days you can get a used Nexus One for the price close to what some parts retailers charge for a replacement motherboard.

  • Well thats the thing, he told me it was $45 for the part, which means he is not replacing the entire board. I guess I will find out when I get it back exactly what part was replaced. Mar 29, 2012 at 18:18
  • turned out i had loosened a ribbon cable and also damaged a some pins Apr 4, 2012 at 23:06

Power Supply is actually a term with some actual, albeit generic, significance and meaning.

In handsets, the power supply is probably(I'm not an electrical engineer, or expert on device hardware) a component that regulates the power supplied to the device (keeping the voltage constant, for one thing), and manages the physical charging/discharging of the battery.

As far as what could have damaged it, it could be anything from dropping/shaking the device if there is a loose connection, to a short caused by water, to overheating. Unless you can find a connection that got loose, and the power supply is indeed fried, you'll need to get it repaired.

If you think there might have been any water damage, put the phone in rice for a day or three, it will dry out most liquid that may be in the device, and it might just work.

  • no there is no water damage, the only thing that makes sense to me is that a component got damaged while I was taking the phone apart, maybe I was too rough with it. Mar 29, 2012 at 18:19
  • It's possible. I wasn't sure about water damage, as you didn't go into detail on how you tried to clean the SIM slot contacts, but it seemed worth mentioning. All it would take is jiggling one wire loose, and who knows what the results will be.
    – Chris Bye
    Mar 29, 2012 at 18:22

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