There's been alot of posts on this lately. There must be a PowerMaster virus circulating and killing them all.
What to do??? It all depends on what you want to do. You could convert to a vacuum setup for a couple hundred bucks, (give or take a lil), if you do it yourself, and be done with it for good. However, if you do not want to mess with that right now, the PowerMaster units are still available as a special order item through most aftermarket retailers such as AutoZone, O'Reilly, Advance, CSK, etc. Usually takes less than 5 days to get it.
The part number for the completely rebuilt, ready to bolt on unit from A1-Cardone is 52-9702.
AutoZone has the cheapest deal on them right now, at about $149. Others show it at about $239. Over the years I've never paid more than $199, but as supply and demand changes, so does the price.
If you want more info on it, you can look it up online at:
autozone.com, advanceautoparts.com, cskauto.com, oreillyauto.com.