FYI Resetting EEPROM seemed to cure my CD70 NAVI of several problems.
The problems I faced were:
Navi kept recalculating route, then just gave a spinning arrow whilst saying "please return to the planned route"
The radio kept losing all sound.
It made a hissy whinning sound even when the power was turned off.
Basically my CD70 had gone bonkers!!
I have seen resetting EEPROM on here but how to get to it was not clear, or to stupid me it wasn't!
Try the following:
Then press and hold SETTINGS until a boing and a message stating "Test mode on"
Now press AUDIO (not BC) several times untill you come to a screen with check boxes - on this screen you will find the words "Reset EEPROM", use the selector wheel to highlight this, then press the wheel to confirm. Wait several seconds and you will hear a boing.
Now press MAIN
Then press and hold SETTINGS until a boing and a message stating "Test mode off"
Giving a fully functioning CD70
Hope this is of help to some of you!!