s4- broken mainboard?

[gomes666]

Hi guys. I come to you for help regarding my niece's Samsung s4. She had it for 2 months and.can't live without it. She went away for a few days and forgot her charger. She used an old trick for a quick fix that involves stripping a USB cable and putting the red cable on positive and black on negative to charge the battery. She had done it before, and so did I with no problems. She says she wedged it between the battery and the phones contacts for a few minutes and the.phone is now a hard brick. I opened the thing and there is.no obvious sign if damage. Is this definitely a hardware fault that requires a new mainboard or can it maybe be resurrected?

Thanks

 

[meyerweb#CB]

Sheesh. You can use ANY micro USB charger to charge any phone with that connector, and micro USB cables can be purchased all over the place for $5 to $10, and people resort to tricks like this? I'll never understand the mentality that prompts people to risk a $600 phone...

Anyway, does the phone show any signs of life at all? When you try to power up the phone, does it vibrate, light up the LED, or anything? If plugged in to a power source via the micro-USB port, does anything happen at all? Try it with the battery in, and with the battery out. Do you have access to another battery, to see if it's the battery that's damaged or the phone?

 

[gomes666]

Yeah u know :S
Anyway no signs of life at all. No lights or vibration, with or without battery.

 

[gollum18]

Hi guys. I come to you for help regarding my niece's Samsung s4. She had it for 2 months and.can't live without it. She went away for a few days and forgot her charger. She used an old trick for a quick fix that involves stripping a USB cable and putting the red cable on positive and black on negative to charge the battery. She had done it before, and so did I with no problems. She says she wedged it between the battery and the phones contacts for a few minutes and the.phone is now a hard brick. I opened the thing and there is.no obvious sign if damage. Is this definitely a hardware fault that requires a new mainboard or can it maybe be resurrected?

Thanks

It probably was overloaded from having the wrong polarization. If someone is going to do that, a multimeter is a must, to make sure you line up the polarity correctly.

Sent from my SPH-L710 using Tapatalk 2

 

[gomes666]

So mainboard is gone for good then?

 

[srkmagnus]

If there's no signs of anything then it's likely bricked. You could try replacing the battery and see if that helps. Otherwise, it needs to be replaced.

Sent from my SPH-D710 using Tapatalk 2

 

[gomes666]

If there's no signs of anything then it's likely bricked. You could try replacing the battery and see if that helps. Otherwise, it needs to be replaced.

Sent from my SPH-D710 using Tapatalk 2

I was under the impression it would come on with no battery when plugged to a pc or a charger. Is this not the case?

 

[srkmagnus]

I was under the impression it would come on with no battery when plugged to a pc or a charger. Is this not the case?

No, it won't turn on. Battery is the cheapest thing to replace at this point. It's worth a shot

Sent from my SPH-D710 using Tapatalk 2

 

[garublador]

So you stripped one end of a USB cable and plugged the other into some sort of USB port/charger. You took the stripped end and put it on the battery contacts on the phone and then the battery on top of the wires.

If that's correct then you put 5V on terminals that are designed for a maximum of ~4.3V. You could very well have destroyed the phone. You're lucky you didn't cause the battery to explode.

The way the phone works is it takes the 5V and runs it into a special Li-Ion charging circuit. That circuit monitors the battery voltage and limits the current if the battery is too low or too high. It won't put any unsafe voltages (like 5V) on the battery or parts of the phone that are not tolerant of voltages higher than ~4.3V. You don't have that guarantee when you just put 5V on there with no regulation.

Next time just plug into the micro USB port. With the screen off it should charge, even if it's kind of slow, from any USB port or charger. Those cables are very easy to find and inexpensive, especially when compared to a top of the line phone.

 

[qxr]

I guess the jumper cables for the car were unavailable.
I hope the niece learned a lesson in patience.

Sent from my SCH-I545 using AC Forums mobile app

 

[gomes666]

so u think not even a new mainboard will help? the whole thing could be fried

 

[garublador]

so u think not even a new mainboard will help? the whole thing could be fried

It depends on what's connected to that voltage rail. I don't know how the phone is all put together so it might just be the main board. I'd guess most of the stuff connected to the main board would be OK. I'm not sure what else would connect directly to that rail. I doubt the display does. I also doubt any of the sensors do either. So it might just be the main board and perhaps any boards between that battery connector and the main board, depending on what's on them (or if there even are any). It's really difficult to say exactly what might or might not get damaged without schematics.