TOMTOM 500 Signal Loss

I have a TomTom 500 which constantly loses its signal for some reason.

If you fiddle with the buttons for a bit it finally works but as soon as you power of the unit and switch it back on it loses the signal and takes forever to find a new signal.

Is this a common problem ???

I have used another tomtom Go 300 without any problems

Has anyone else experienced the same problems, if so did they make a complaint.

I have the 700, and it only loses signal if there is a major obstruction stopping it viewing the sky. It gets a fix within about a minute when switching on, or after losing signal; (given a clear view).

I've had a 300 for a couple of months now.

For the first month it worked perfectly and then started to lose its signal regularly.

By regularly I mean every couple of minutes. No bars showing and the screen would show me in the middle of fields.

I just reset to factory settings and it seems to be fine. I thought i might lose the poi's but it didn't happen. I just lost set preferences and recent destinations

rod