When I put a SMT part on the copper bottom, traces on that side show no connection.

[NevadaDave]

I am doing a board (using Ultiboard 13) that is double-sided SMD. I have some parts that I put on the bottom layer (using the "Swap layer" command) and I find that traces on that layer do not show a conection to the pad that I want to use. The pad correctly shows the net assignment, and if I put the part back on the top of the board, the connection is good. Ultiboard acts as if it wants to connect on the top side of the board instead of the bottom. The Gerber file output is correct (ie. it shows copper correctly) but I'm getting tired of constantly getting this error. Is it a part problem (i.e. is the footprint incorrect somehow) or is it a bug in Ultiboard?

[Tien_P]

Hi Dave,

I am not aware of any bug similar what you have described; if you can post an example showing this problem it would help me better understand this problem. I created an example using the swap layer function for U2, as you can see; I can run a trace on the bottom layer connecting to U2.

[NevadaDave]

Tien.

Attached is a file that shows unconnected pins (Q1, pin 4, and Q2, pin 4) that should be shown as connected. I originally thought this was a layer swap issue, but apparently it is not just that, as it appears that there is a different connection problem, even on parts that have not been layer-swapped.

[Tien_P]

Hi Dave,

Thank you for the file, I was able to see the problem.

I think there is a connectivity check problem in this case. It appears that when the soldermask layers or the paste mask layers are enabled in the Design Toolbox, Ultiboard gives a false connectivity check error. Uncheck these layer and run the connectivity check and the error is gone.  I don't see a problem with your connection.

I will provide your file to the developer, hopefully, they can address this issue.

[NevadaDave]

Tien,

Sorry about taking so long to get back to you, lots of stuff going on! I found that, just as you said, if I disable (completely - not just "greyed out") the solder mask, connectivity is normal. Hopefully I'll remember this in the future!

Thanks!