KTM 300 exc Digital Dash

When i bought my KTM300exc the digital dash wasn't working. Since i'll will be riding on the road, its always useful to have a working speedo, so i set about trying to get it to work.
First thing i fund out was that the KTM OEM speedo have an internal battery, so i popped to Maplins, bought a battery and replaced the dead one.
To access the battery there is a screw off panel on the back of the unit. Its easier to remove the unit from the bike to change the battery.

With the unit removed from the bike I inserted a large coin (i used a British 50p coin) and twisted off the battery cover.
Once the battery was replaced i managed to get some life out of the speedo, however the big function button on the right hand side didnt seem to work. All i could get on the screen was the speed and the time. no way to adjust the time as the buttons didnt work :(

So it seems my speedo might be broken. When i get some spare time i'll strip it down and see whats inside... Or i might just buy a new Trail Tech digital speedo.