Is there anyway to fix a (9V power) burned pi

Question

I think I accidentally connect a 9V battery pi to the pi and it flashed and turned off.

I think I might burned the pi by doing that because I'm not able to boot it any more.

So now if I connect the normal power cord to the pi, both red and green led light up but no flashing.

I tried to refreshing the os on the sd card and tried other working sd card as well, same problem stays.

Anyone has any suggestions of what to do? Is there anyway to fix the burned pi?

Thank you.

rew · Accepted Answer

The processor in the raspberry pi is a "smart" thing. It has a built-in DCDC converter to facilitate making a smartphone or other battery powered device from this processor. This means that the processor is directly connected to the input power. It is not the case that say a DCDC converter chip is connected to the input and that such a chip might have blown and shielded the important parts of the pi from the damaging voltages. Some chips have a "margin". i.e. the manufacturer tells you "no more than 12V", while in fact the chip will survive 15V. However modern chips, and especially chips that include fast processing stuff the margins are really small. The specs on the BCM2835 SOC (and its successors) say 5.5V, but I don't expect it to have any margin bigger than about half a volt. It'll break down permanently around 6V. :-(

rew · Answer

The SMB family of TVS devices is big and easy-to-replace. They would normally sacrifice themselves by shorting the powersupply. That would leave you with a "dead" pi (no lights, no nothing). If your powersupply is then strong enough, like I would expect from an ATX powersupply, it will blow even the sacrificed protection diode to bits. THEN the full 12V will be applied to everything originally 5V on the pi.

Obviously you're not in the "completely dead" stage. And probably also not beyond that: then things would be way worse than "attempts to boot".

So what I think might have happened is that the 12V was reduced to"just above 5V by the TVS and it didn't quite blow But the other stuff on the board then did get that"just above 5V for a while This exceeds the 5.5V max for the CPU(check the datasheet I didn't If you still suspect the SMBJ5.0SMBJ5.0 to be broken the board will work without it You just have to promise that you will NOT apply the wrong voltage to the board until it gets replaced So the SMBJ5.0SMBJ5.0 tries to keep the voltage in the-0.6 to 5.5V range and it will help keeping things in one piece if you go outside that range If you are very careful you should be able to run without it My recommendation is to replace it eventually but you can first test if things work by removing it

Robert Peter Oakes · Answer

Then this is the forst place to check as the input has protection and a zener See if the 5V on the right side is working when you are powering the device from a correct power adapter

Robert Peter Oakes · Answer

to be honest, it is not economically viable to fix unless you had the parts and tools. even then it may not be as reliable due to potentially other partly damaged parts, Should come with a label saying NO SERVICEABLE PARTS INSIDE A golden opportunity to upgrade to a model 3

rsc · Answer

Depending on what's cooked, you may be able to fix it. Look at the schematics for your board and start testing points with a voltmeter starting from the power supply. Check the 3v and 5v pins on the GPIO header first. https://github.com/raspberrypi/documentation/tree/master/hardware/raspberrypi/schematics If the LEDs are still on, it's hard to say where the problem is. Scott

rew · Answer

"Permanently damaged" wouldn't be very bad if the blown component was cheap and easy to replace. In this case the damaged component is likely the CPU. It is not very expensive (but impossible to obtain) and very difficult to replace.