Patrick;
Before sending your unit away, check the reed switches located inside your battery box. These are little black cylinder thingies that the battery wiring go through. These are switches that need a magnetic field to allow a current to pass through. When you switch on, magnets in the switch get close enough to the reed switch and they allow power to the electronics.
Sometime these fall out of the little groove that they're supposed to stay in. Check that it is in place.
Hope this helps
.