I know this is a stupid question. However on my commute back home, I noticed that speed was no longer showing on the readout. I stopped and had a fiddle with the detector on the fork but without any success. Got home and spent a very frustrating quarter of an hour fiddling with the magnet and detector to the extent that they were about a micron apart and it still would not pick up the turning wheel and give a speed read out. Any suggestions?