For non-invasive method, locate the intrusion switch (as pictured) and using tape to keep the switch in depress position, as if the top cover is still closed. For permanent solution, remove the intrusion switch wiring from motherboard connector and short the connector pins with jumper. [IMAGE] [IMAGE] 12.  Intrusion switch connector 
Hello, is it possible to configure Dell Precision 3930 the way we could open chassis while workstation is running? When I do it now, it beeps and approx after 3 seconds it turns off. I was browsing BIOS setting and there was settings with "chassis intrusion" with 3 different options, but neither one led to the desired result. It always beeps when it is open and then turns off.   On the other hand, we also have Dell PowerEdge R350 and I don't even need to configure something, it works that way - I can open chassis, it doesn't even beeps, server keeps running, it only increases fan speeds. I desire this for Precision 3930 as well.
Dell Precision 3930 - open chassis while running