Daktronics DF-4000 - Manual (Page 22)

Maintenance and
Troubleshooting
4-4
4.6 Lightning Protection
The use of a disconnect near the display to completely cut all current-carrying lines
significantly protects the circuits against lightning damage. The National Electrical
Code also requires it. In order for this device to provide protection, the power must
be disconnected when the display is not in use. The control console should also be
disconnected from power and from the signal j-box when the system is not being
used. The same surges that may damage the display’s driver can also damage the
console’s circuit.