It appears I have a dead driver in one side of my 250 ohm Beyerdynamic DT770s I purchased in 2008 (thread here). I got them on sale for $113, so it doesn't really seem worth it to buy a pricey replacement driver from the factory (especially if they retail for ~$75 each on the UK website).
Would it be worth it to find some other drivers of a comparable size and swap them in? It seems like at least one person has done it before with Audio-Technica drivers.
If so, what kind do you recommend? It looks like my current drivers are 45 mm.