Why does autorouter revert to 98% after reaching 100%?

Question

I managed to route an entire complex board with eagle, or so I thought. At first it worked. Then I began adding large fills (ground planes and VCC planes) in order to minimize impedance.

I now added extra circuitry to my board and manually routed those parts in place.

I now run the autorouter one more time and watched the progress. In all optimize stages, it showed 100% which made me think everything went perfectly. Then after it was done, it reverted back to 98% (1 unrouted wire left).

I turned off the copper layer on the board as well as the grid and I couldn't see where this unrouted wire is and I even zoomed in.

Is this a bug that exists in eagle when I define multiple planes close to each other? or is there some other trick I can use so eagle can stay at 100% instead of reverting to 98%?

Answer 1

Ok so I figured crazy eagle. Yes I'm using 4.16 which is old, but I found the trick.

Even though the part pad is on the correct track, there is a bug in Eagle which won't correctly autoroute the part is the track is previously made.

So the answer is to move the part so the pads do NOT touch any of the existing tracks then run the autorouter then it will complete that track.