connect power in reverse :( - Printable Version

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connect power in reverse :( - nhzgroup - 05-21-2019


I mistakenly connect power cord in reverse and something on the board exploded ! 

Is there any way I can change a component to revive the board? 

regulator chip or sth?


RE: connect power in reverse :( - dkryder - 05-21-2019

oh heck, that's a bad feeling i know, i've hooked up 9v to a 5v sbc before. best you can do for starters is get the datasheet and/or schematic and as powerful a magnifying glass as you can, like a 10x or 15x and spend some time just looking at it for burnt or exploded components. if you got a good zoom camera take a few good close-up shots of each side of board and post them here.

RE: connect power in reverse :( - nhzgroup - 05-22-2019

Thanks for the reply,

exploded chips plotted with red circles.

do you know the names so I may replace them or just remove them and test! Smile)

Thanks agin,
[Image: WsfXFfG][Image: 20190522-121152-HDR.jpg]

RE: connect power in reverse :( - fire219 - 05-22-2019

The full schematics for all the P64 boards are available on our Wiki. What you're looking for U2000 and U2001 on sheet 11 of the RockPro64 schematic.

The part number for those is SY8113B. If you have a hot air soldering station, tweezers, and a very steady hand, you may be able to replace them.

RE: connect power in reverse :( - nhzgroup - 05-23-2019

Thank you, I will, do you think other components might also be damaged?


RE: connect power in reverse :( - fire219 - 05-23-2019

(05-23-2019, 10:14 AM)nhzgroup Wrote: Thank you, I will, do you think other components might also be damaged?


It's impossible to know for sure without testing it. Luckily, those DC regulators are pretty early in circuit, so there's not much which is likely to be blown by this. The main thing which I may be concerned about is D2000 (diode). I do not have an RP64 on hand to check right now, but it may be the skinny black component just below the 4pin connector in your image.

I was not involved in the design of the board, but it's likely that D2000 is actually supposed to prevent reverse polarity damage (sadly didn't work here). It could be just fine (good, obviously), failed open (not ideal, but won't stop the board from working), or failed short (likely to get very hot and maybe burn up itself and/or board traces).

RE: connect power in reverse :( - pfeerick - 05-24-2019

A diode in that configuration is only good for protecting against reverse voltage if there is a fuse in front it (as it is supposed to present as a short), or you have a current limited power supply that can't make it go 'pop' and let the magic smoke out... as a short-circuit is the typical failure state of diodes, not open... so you don't want them to fail when protecting something!  Dodgy Sad 

As fire219 pointed out, those regulators are early in the circuit - one providing 5v to the rest of the system, and the other providing 5v to the USB ports. So hopefully they took the lot and blew out... otherwise, you can pretty much write that board off... as next up would be the main RK808 power management IC... and if that got fried also... the CPU and peripherals are toast.

There are four components likely to be decreased in the first instance... 1) polarised capacitor C2001 2) diode D2000 3 & 4) SY8113Bs U2000 and U2001 -can't tell which is which from a quick glance at the board. If you were an electronics tinker, you could put a current limited 5v supply on the GPIO 5v and ground pins... as it seems they are attached to the VCC5V0_SYS... so it should at least boot if it's going to? You'd want to get rid of U2000 and U2001 first in case they're shorting anything, and are dead anyway as they've let out the magic smoke.

btw, if you had anything on the PCIe bus, it's probably toast as well, as the reason the rockpro64 needs 12v is that PCIe has 12v...