Blank screen confusion- please read

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Hi all,

I came here because I understand you all are the gurus of BMW nav systems!
I have a 2000 540iT with mkII nav.
I had the screen going blank like this sporatically for a while:


It would sometimes be fine, sometimes do this. Sometimes a simple turn on-off of the key would "fix" it.
Then it went blank like this and never came back. The radio still worked as did the CD changer.
Then the entire ibus system went down- no radio, turn signals, reverse lights, PDC.

I troubleshot the system for what felt like the entire day yesterday- finally I removed the nav drive and the i-bus came back to life. Radio, turns, reverse all work again but the screen was completely black (no illumination or stripe). The Nav drive's pink color plug had some corrosion on it. I cleaned it all off and hoped for the best. Plugged it back in and no luck, but the screen is illuminated and has the stripe again.

Am I right in assuming the drive is just bad? Are there any things I can try to bring it back from the dead before hunting down a new unit?

Thanks so much for reading guys, and in advance for any info you can share!