PMIC fries if 5V is shorted to 3V3 on GPIO header

Hardware
1

I just fried my Renegade.

I was working on setting up my Renegade, when a metal screwdriver that was sitting on the workbench came in contact with the far-corner pins on the GPIO (near the IR sensor). It was very brief, just a fraction of a second, and poof – the Renegade was dead.

At first, I thought the 5V pin had shorted to GND, but I think it’s more likely that 5V shorted to 3V3 since those two are right next to each other at the end.

I noticed the other corner of the board near the USB jack was warm, so I initially thought maybe there was a self-resetting fuse there that needed to cool off, and I’d be back in business after a few minutes. Nope. I pointed my FLIR camera on the board and saw a bright glow where the RK805-1 power management IC is.

I understand that the GPIO pinout basically follows the “standard” Raspberry Pi pinout, so this might be a possible problem for all SBCs like this and not just the Renegade.

So this isn’t a request for support, exactly, just an announcement to others to be careful and pay attention to the area around your SBCs, and to alert that it’s VERY easy to fry your Renegade if anything conductive comes near the edge of the GPIO header.

I think I can replace the RK805-1 PMIC so that I don’t have to throw this otherwise brand-new Renegade in the trash, but so far the only place I’ve been able to find that IC is on AliExpress. Do the folks at Libre have a way for me to get that part?

2

The salvage value is around $5 if you manage to recover working SoC and DRAM chips if the damage is anywhere besides cheap surface mount components. We don’t have a recovery line for this board and it’s not really worth shipping back to a distributor and then back to China for repair. The only place to really source replacement parts is AliExpress which takes a month for a PMIC. If the 5V and 3.3V shorted, you have to take a look at the schematic to see what other things can possibly be damaged by a surge current on the 3.3V line.

We have seen people put boards on bare metal cabinets and tables and then plug in power :sweat_smile:. You’re not alone and definitely not the first. We do recommend to put these SBCs in a case to protect it from accidental shorting.