My sigma sport onboard computer isn't registering my speed or distance at all. I had a fall about a week ago, and haven't used the bike until yesterday. The computer is still on and working (well, the clock is still accurate) but there may be a problem with the connection between the magnet and the computer. The magnet and sensor are still where they were, not jolted out of position, so I'm not sure how to pinpoint what the problem might be. Everything looks to be connected. I'm not even sure where to start looking to fix this.

The magnet, as you might know, induces a very small current by wizzing by a winding with a small iron core to make a blip of electricity. The controller needs very little blip to register anything, so the first thing to do is to put the bike upside down or in a repair stand, and adjust the magnet and pickup coil so that the magnet is as close as you can get it to the pickup coil. Spin the wheel fast and see if you are registering anything. If not, it is time to pop out the ohm meter and take the computer off its mounting (leaving the bracket there on the handlebar) and check continuity by putting the ohm meter on DC voltage 1x scale, hook the leads up to the nodes that are seen on your handlebar computer bracket, spin the wheel and look for movement of the needle on the ohm meter (or change in a digital readout on a digital meter). If you don't see this, fix the open in the wire. Most likely it is not your computer, but it could be.