>one of the magnets broke off the screen

I had a similar event (but only once) supporting university labs: one of those four "alignment pins" broke off; but they're not necessary once the magnets are engaged. Unfortunately, I had to completely re-disassemble the entire unit to shake out that metallic-breakoff.

The 2006 iMac is a dream to work on: the back plate (including stand) simply detaches, exposing access to everything without having to remove the LCD – this latter part is the worst part of any newer iMac-opening.

Thanks for sharing your similarities, fellow-oldening-hat.