It's been about 10 years since I sent anything off to Paul at prodig. But back in the DAT day, I sent him portable and full size DAT decks probably 6-7 times. Seemed like no matter what was going on or what the repair was, the bill was $200-250.
Given that rates have gone up over the last decade, I'd guess the repair bill will be in the $250-300 range. I'd probably put out an ISO in the yardsale for a working DAT deck, esp a full size deck rather than a portable. A full size deck would probably go for cheaper used and it's transport is probably more robust than a DA-P1.
I don't think I'd get it repaired, unless you can't drum up one from ts.com.
I need to get back to transferring DATs, those master tapes aren't getting any younger.