OrCAD Layout GND problem

[Jeff]

Hello,

I have been using OrCAD Layout Plus for 15+ years with minimal issues, currently using version 16.2. However, I am having a problem with my GND connections after I ECO a new netlist into my L/O. In all the years of using OrCAD I have never had a problem like this. I have been working on my current L/O for about a month now and have had some problems where GND connections are not clean (the guide doesn't disappear when the trace is routed even though it looks like the connection has been made). I figured out a way to deal with this but it's tedious and not a real solution. I use the Pin Tool to disconnect the affected pins/pads and Free Vias from the GND net then use the Connection Tool to connect those affected pins/pads and Free Vias back to the GND net. I finally completed my L/O and verified using the Statics Spreadsheet that 100% of all nets were connected, so then I performed a Back Annotation out of L/O and into my OrCAD Capture Schematic file. There were no connection changes or parts added to the Schematic. At this point, I generated a new Netlist and ECO'd it into L/O. The new L/O file was opened and I have many connections that are either unrouted (124) or partial (113) routes (with 582 routed), all of which are GND. All of the traces and vias are still in place but there GND guides everywhere.

Another interesting thing is that when my L/O was complete (before Back Anno) the statistics spreadsheet said that 100% of 761 connections are made. The newly netlisted version total would be 819 connections (124+113+582, see above), not sure why there would be 58 more connections.

This PCB is 4 layers and Layer 2 has quite a bit of GND pour but some traces too. There are no gaps or voids in the GND plane that would cut-off or isolate GND connections.

Does anyone have an idea what may be going on here? Any help would be much appreciated!

 

Thanks in advance,

Jeff