Express 250 overloading Strand node.

Does it only happen with your one Express 250?  Or if you have another console, does it happen with that as well?  Having access to a DMX test tool is a great thing.  ETC recommends the Gizmo from Doug Fleenor Designs to their field techs, and a lot of touring  stage electricians like the Swisson DMX test tool.  Personally, I'm preferential to the Goddard Designs Lil DMXter and MiniDMXter, but any of these would allow you to test the output from your console or the input to your node without too much trouble.

Swapping the cables is a good start.  For further troubleshooting  I would try the following-

1) Try another DMX source. (DMX test tool, a different console if you have one, the output of a DMX splitter, etc.)  If the problem happens on the Strand N21 node anytime you plug a DMX source into the node, it likely is something wrong with the node itself.  If it's a two port node, try the other port on the node to confirm if the problem is limited to one port or the both.   As far as consoles go, it shouldn't matter what console you try (Smartfade, Leprecon,Leviton/NSI, Strand, Hog,  GrandMA, etc.) as long as it outputs DMX.  If you don't have another console, try a DMX Repeater, and use one of the repeated outputs.  Otherwise, try the next step.

2) If the node behaves normally with another source, but shuts down when using the Express,  it may be something on the Express.  Try the 2nd DMX port (513-1024).  If it behaves normally with the Port 2 DMX output, and doesn't behave normally with DMX Port 1, then your Express may have an issue that needs to be repaired.  Again, if you suspect port one is the issue, try using a splitter/repeater in line with the node input.  This may clean up or isolate the two devices from each other enough to get through your show.

In either instance, a quick call to either manufacturers tech support should give you some added info and things to try.  Also, don't forget to use your local dealer for support as well.

Good luck, and do post your findings, as it may help another tech on down the road. 

Does it only happen with your one Express 250?  Or if you have another console, does it happen with that as well?  Having access to a DMX test tool is a great thing.  ETC recommends the Gizmo from Doug Fleenor Designs to their field techs, and a lot of touring  stage electricians like the Swisson DMX test tool.  Personally, I'm preferential to the Goddard Designs Lil DMXter and MiniDMXter, but any of these would allow you to test the output from your console or the input to your node without too much trouble.

Swapping the cables is a good start.  For further troubleshooting  I would try the following-

1) Try another DMX source. (DMX test tool, a different console if you have one, the output of a DMX splitter, etc.)  If the problem happens on the Strand N21 node anytime you plug a DMX source into the node, it likely is something wrong with the node itself.  If it's a two port node, try the other port on the node to confirm if the problem is limited to one port or the both.   As far as consoles go, it shouldn't matter what console you try (Smartfade, Leprecon,Leviton/NSI, Strand, Hog,  GrandMA, etc.) as long as it outputs DMX.  If you don't have another console, try a DMX Repeater, and use one of the repeated outputs.  Otherwise, try the next step.

2) If the node behaves normally with another source, but shuts down when using the Express,  it may be something on the Express.  Try the 2nd DMX port (513-1024).  If it behaves normally with the Port 2 DMX output, and doesn't behave normally with DMX Port 1, then your Express may have an issue that needs to be repaired.  Again, if you suspect port one is the issue, try using a splitter/repeater in line with the node input.  This may clean up or isolate the two devices from each other enough to get through your show.

In either instance, a quick call to either manufacturers tech support should give you some added info and things to try.  Also, don't forget to use your local dealer for support as well.

Good luck, and do post your findings, as it may help another tech on down the road.