I learned something valuable about my trusty Nikon SB-28 flash the other day. I use this strobe in an off-camera arrangement, triggered by a CyberSync radio remote. I have always been annoyed with the operation of this setup in one respect: If I delay taking a picture for a while (1 minute, 20 seconds - I sat down and tested it) the flash becomes unresponsive. The next picture I try to take will result in a 'test' fire. This is highly disruptive to miss shots after this delay because something is asleep. I always thought it was the CyberSync receiver. However, correspondence with them tipped me off to Nikon's standby mode for strobes.
In standby mode, if the flash is not used for 80 seconds, it will put itself to sleep. For on-camera operation, it's not that big of a deal since depressing the shutter button part way (to focus) will wake it up. For off camera operation, it can completely disrupt a photo shoot.
You know the flash is in standby mode because the letters 'STBY' are displayed on the right side of the strobe's LCD.
Turn the flash off by pressing the ON/OFF button.
Next, hold down the 'MODE' button while turning on the flash with the 'ON/OFF' button. The flash will turn off and you should notice the 'STBY' icon missing. If you ever want to switch it back into standby mode, simply reverse these instructions.
This procedure is specific to the Nikon SB-28 Strobe. It might work for other Nikon strobes in this era; check your owner's manual to know for sure.
Yes, there sure is. The reason standby mode exists is to conserve power if you leave it on. With Standby mode off, the flash will continue topping off the internal capacitors to stay at the ready for any moment. Over time, the flash batteries will deplete. If you are doing a long shoot, such as a long event with a presentation or other delay in the middle, the flash may die before the event is done. Also, you have to remember to turn off the flash when you are finished; otherwise, it will be dead upon the next use.