I now know a bit more about your toilet...
I forwarded this thread and your photos to Vic Willman, tech services manager at Raritan. His reply:
It's a Raritan Jett Head, using an Atlantes bowl. We sold a number of them, back in the early 90's. It didn't have a joker valve in it. It used a high
volume, remotely-mounted supply water pump that blasted everything out by forcing a high pressure flow of water through a 1/4" nozzle in the base of the toilet. It broke everything up and blew it out through the rear of the unit. We offered them in both 115 volts AC and 12, 24 or 32 volts DC.
The DC versions used a 3/4 horsepower motor that had a centrifugal pump head mounted on it, from the Hayward Swimming Pool filter company. They drew a tremendous amount of battery power (70+ amps) for the duration of the flush (approx 10 seconds) and used 3-5 gallons of water per flush. These days, they're pretty much of a dinosaur, and we no longer support them. The AC
versions used the standard 3/4 horsepower Hayward Swimming Pool filter pump complete, with strainer.
They worked pretty well, but the motors didn't hold up and as a result, the pumps rarely lasted more than a few years. I still get requests for replacement pumps and/or motors for them, but we can't supply them any
longer. I usually refer them to Head Hunter, who makes a similar pump, for their replacement pumps.
Neither version was ever a high volume item, we only sold a couple dozen per year, if that. They were used mostly by commercial fishing and other work boats that spent the bulk of their time at sea and so mostly discharged directly overboard.
He also attached a couple of PDF documents--manuals for it. I'll be glad
to attach em to a reply if you'd like to email me. (EMAIL, not PM)
After reading his reply, I'm even more convinced that you'll be a LOT happier with new toilet. Check out the Raritan Elegance:Raritan Elegance toilet Practical Sailor rated it "best in show" in comparision of every major macerating toilet earlier this year.