Charles,
Do you have Nova brand strobes? If so, they have multiple settings for flashing the strobes. Try switching to a different pattern. If that clears it up, you probably have dirty switch contacts. Did the system sit for more than a year unused? If so, long time lack of use causes the capacitors to break down. Sometimes it's possible to "recondition" the capacitors. If not, you could open the box and change the capacitors, if you are handy with a soldering iron. Be VERY careful inside the box. Be sure to drain all the capacitors prior to working inside. Otherwise you will get a really nasty shock. Maybe you have a friend who is handy with electronics who could change them for you?