Replacement Sat Nav drive

Hi,

My navigation has been playing up for about 6 months. Initialising at start up, not working at all and not displaying maps.

I opened the DVD drive and cleaned the lens and got a few more months but now it normally fails to display the map.

I sourced a used unit from a trustworthy breaker buy this and the following unit he sent both will not initialise, asking me to check the nav DVD.

Ive had the unit checked for component protection and confirmed compatibility with Becker UK.

The unit came with a copy 2011 disc. Ive tried 3 known working copies which will work in my old unit but have no genuine one after my wife broke the original slamming down the armrest on top of it.

Could there be a software conflict between the donor unit software and mine which is running 4220?

Could I fit a new Fujitsu loader deck to get my original unit working or does this need programming into the nav drive DVD unit?

Any thoughts or advice greatly appreciated.

Neil