You probably just have a defective Sync Cable going to the main strobe, replace it and all should be fine. This strobe unit also is designed to work as a \"Slave\", meaning when it sees another strobe go off it will fire also. That is the reason it fires when the pop up flash goes off.
The smaller strobe mounted on the inside of the larger strobe is designed only as a slave unit, you would be better off using it elsewhere and replacing it with a regular incandesent light bulb for the intended use of a Modeling Lamp on the larger strobe.
Nov 11, 2009 at 10:08 AM
Previous versions of ACElkins's message #7761258 « Studio Flash Only Fires W/Pop-up »