Help me figure out how to jumper C12

[nate-o]

I royally messed up my board. I installed the wrong cap at C12, and when I un-soldered it, I ruined all of the solder pads on C12.

Looking at the board, it looks like C12 goes to pins 1 and 2 on the LM317. This doesn't agree with the schematic, it looks like the positive lead goes to ground, and the negative lead goes to D5, R26 and R27, and then pin 1.

My only idea to salvage the board is run a couple jumpers on the backside of the board. I'm guessing jumper from + to R25. As far as the negative lead, I'm not sure where to start.

Any help would be great. I'd hate to have to send it back to Tim for a new one.

[nate-o]

I had my electrical engineer buddy take a look at the board. He was able to fix it with a small amount of copper tape. My multimeter doesn't measure capacitance, but using resistance it looks like it's a connection.

He did suggest that the heat sinks around the solder pads should be about 3x the size, although that may be hard to do with some of the smaller pads.

[tpryan]

heat sinks around the solder pads should be about 3x the size

I'm afraid I have no idea what this means. Standard practice in the industry is for pads to be 2x the diameter of the hole. Most of the pads on our boards exceed that so they can withstand rework though, as you discovered, they're not indestructible.

[nate-o]

I don't think I used the right word for it. I don't remember what he called them and I don't know anything about circuit boards.

Underneath the solder pad, there are little lines, they look like a + sign with the component hole in the middle of the cross. The lines are a blue-ish color and look like conductive traces.

I assume that those are the heatsinks for the solder pad, or are those how the solder pad connects to the rest of the board?

My friend designs and manufactures giant one-off oscilloscopes for lab work. For his application, he said he liked to make the lines under the solder pad bigger when space allowed.

It's just an opinion, take it or leave it. I thought it might help you, so I shared it.

[tpryan]

I assume that those are the heatsinks for the solder pad, or are those how the solder pad connects to the rest of the board?

Oh, you're talking about the thermal reliefs, or thermal spokes. They connect pads to surrounding copper planes. The wider they are, the harder it is to solder the pad with a small iron.