sounds like there are being two issues discussed here.... one is the 5 or 6 orange bulbs that backlite the pixels and second is the infamous burnt out pixel issue.
I have a 99 540i6m and just had a repair done on my pixels (vdorepair.com--excellent deal--$200 to repair vs $800 for the dealer) and in doing so came across the 5 or 6 (cant remember now) light bulbs that actually light up the pixels. For giggles i removed the lights (thinking that maybe that had something to do with burnt pixels not being displayed--it doesn't BTW) and plugged the cluster back into the dash and voila... no pixels at all.... unless you looked at it from different angles and then could see the 'live' and dead pixels.
based on the problem description... sounds like one of the bulbs died... not the pixels. When the pixels go, it seems to affect the entire display, making it look like some kind of alien language. You might as well replace them all whilst the dash is cracked open.
If you go to vdorepair.com, they have a section on how to remove the vdo (instrument cluster) so that you can access the bulbs.
---1999 540i 6M ~techno violet~ Dinan S2---