I have a pair of Monitor 5JR+ I've had since the late eighties (IIRC) which I'm sort of attached to, but one of them has both woofers blown (well, they make no sound). You can still buy parts for them on eBay and I could probably get them like new for around $150. There's probably more wrong with them, I abused the hell out of them when I was younger.
Would it just be better to buy a new pair, say, of Tsi200's? It's been so long since my 5JR's sounded good I've forgotten what they're supposed to sound like. They're currently the "B" speakers in a system I generally use for movies along with a pair of inexpensive Sony floorstanding speakers. Considering pairing them (or something else) with my Tsi500's on another system.