I have the same one - real quality and long lasting. It has been great and we have had no problems with it for over 10 years and the previous owner for about 5 years before that. It has been uncovered and exposed to the harsh salt water and air for all of that time. The Japan Radio Corporation (JRC) has mostily made quality large commercial radars and I am not sure they even make these small sport boat radar systems anymore. If I had seen this one earlier I would have bought it for spare parts. Having it stand alone from your other navigation systems is in my view a saftey feature.
If it does not come with the manual, you are welcome to a photo-copy of my manual. I am in Victoria. Send me a private message with your phone # if you need it.