How do I jump from trace here?

Question

I've been asked to reattach the positive cable that got ripped with the pad from a board given that I own a soldering iron. It seems simple enough to just jump it from a trace.

Scraped a bit of the mask off from the pad space at P1, yet I don't get anything at all while measuring for continuity from the negative cable to the exposed trace.

The whole board is covered in some resin if that helps.

As I see it the big traces starting in P1 are clearly separated so those should be the negative and positive sides so the magic pixies should go from one side to the other, but they seem real lazy.

What am I not understanding?

Edit: this board is for showing battery level on some boat, theres a counter soldered on the other side

Answer 1

The resin is most likely some kind of conformal coating, which shouldn't be a big deal. If you are trying to measure continuity, you can follow the + trace to other components on the board. R12, C1, and C2 all have leads that touch the + trace, so once you have re-soldered the wire (next to the "+" pad) you can check continuity between the wire and one of these components.

Answer 2

Power on P1 is connected but GND is not on the other pin (black Wire?)

Ensure you have continuity using a needle elsewhere to GND and clean P1 pad with razor blade scrapes lightly.

Lightly surface coat with solder without filling hole. (Solder tin coat each before bonding preferably using the hole.)

Insert short solid wire in hole, fold and solder. Then reconnect to short solid wire with heat shrink using mechanical twist strength and minimum solder to coat surfaces.

Then for final strength add a dab of sub-floor adhesive and let that be your strain relief like plastic insulation and mechanical support with electrical insulation .

Then you can yank the wire pair as hard as would want if lightly coated from PCB P1 to a couple cm or 1” away.

They use white stuff inPSU’s for big leaded parts but it not avail in DIY shops yet subfloor adhesive Polyurethane is dirt cheap in a tube but the non-volatile stuff these days takes a day to get to -≈50% hardness exposed to air and harder after that. when tapered you have perfect strain relief. Apply like paste with a disposable tool.

Answer 3

There shouldn't be "continuity" between the two pins for P1. You'll probably be able to measure some kiloohms of resistance between the two, but that won't tell you anything useful.

P1 has two pins, marked "+" and "-". You've got the red wire attached to "-". I hope that doesn't mean you connected the positive wire of a power supply to the minus pin. If you did, then you might have killed the circuit.

The "+" wire was torn off. It was connected to the large area to the right of the torn pad. You should be able to just scrape some solder mask off of that large area and solder down the wire.

The board might be double sided, though, so you'll have to flip it over and see what's on the other side of the torn pad. If there's nothing there, good. If there's another trace leaving from the top side, though, then you'll have to add another wire from the large "+" area that goes around to the other end of the torn pad on the other side of the board.