Inky Frame battery leak damage/expansion header connections

Support
1

My Dad’s Inky Frame has unfortunately suffered a battery leak which has run straight out the battery case and looks like it’s pickled into a couple of thru holes down by the bottom pin of the expansion header:

PXL_20250101_183834341
PXL_20250101_1838343411152×995 408 KB

(subtle, but look for the green discoloration)

Unfortunately connecting it to USB power makes hosts give overcurrent warnings and what I believe is the voltage regulator on the Pico W heat up (getting a singed finger from one of the adjacent chips trying to hold the BOOTSEL button is what lead to discovering the damage). So this has presumably caused a short somewhere.

  1. The 3V3 pin on the header has continuity with both other negative pins and the battery negative terminal. (Negative doesn’t have continuity with positive, at least.) Is that expected? The schematic labels negative as ground and 3V3 coming from the Pico’s 3V3OUT pin, so I assume it should instead be positive on normal operation—if so, there’s the problem.
  2. Is there a reasonable way to peel up the decoration on the back of the board? I’m not sure if it’s a really well-fit vinyl sticker, or actually fused onto the board somehow. It seems that’d be the best way to inspect the damage better and see if there’s a way to fix it. I don’t believe there’s an actual PCB diagram up anywhere to check if corrosion there could cause this?
  3. And…does anyone have any bright ideas how to cut this short, if my hypothesis is right? It’s a shame to discard the whole board when all the interesting bits (the e-ink display, the pico itself) are probably fine. The expansion header isn’t being used.
  4. Failing that, is there a reasonable way to at least unmount the display and Pico as spares? Are they mounted with glue?

Thanks…and be careful with those darn double-As out there.

2

Isopropyl alcohol and a toothbrush can be used to clean residue off of electronics. It’s what I use to remove the flux residue after soldering. It will also clean off the battery acid residue. Ideally you want an antistatic brush, but I’ve used a toothbrush in a pinch without hurting anything.
iFixit Anti-Static Brush

3

Unfortunately this is post-cleanup (didn’t get a before photo). I assume those tiny holes (there are others around the board) are connections through to another layer/the other side of the PCB (under the display), and there’s unseen damage under the decorative flower pattern.

4

They maybe vias. I do believe the vias are normally filled in with solder? Some may also be markers for the pic and place machine. Actual holes are sometimes for support legs to mount to. Pimoroni Tech Support can give you exact info.
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5

Those small holes are certainly vias. And they are not filled with solder (at least that is not the purpose). They connect different layers. If you want to learn more about vias, I found this article helpful: Via Covering: Tented, Untented, Plugged, Epoxy-Filled and Copper-epoxy-filled

@LionsPhil Having something in the vias alone is not the problem (they do “short-circuit” multiple layers already without filling). But I think the battery chemicals which are aggressive caused other problems like shortening 3V3 to ground. And given your analysis I would certainly not use the InkyFrame anymore.

So because you have nothing to loose, try scraping of the silkcreen very carefully. Also inspect the connector. Whatever you do, check 3V3 against GND as you did before. As long as there is a short, you did not solve the problem.