I am admittedly NOT an electronics guy, but this should not be so hard. I have a RAYSTAR 120 GPS receiver (SeaTalk version). It is interfaced via a Raymarine E85001 Interface unit to a Cetrek ProPilot 700 autopilot, a Furuno radar and a USB cable to my laptop (w/ MapTech chart software). That is how I bought the boat and the previous owner had no idea how to make the system work. Anyway, I loaded up the software onto my laptop a year or so ago and had it working just fine until last weekend...then, nothing.

I have checked all the connections and they look good as far as I can tell. I've inspected the receiver unit and can see nothing amiss, although it is pretty much a sealed unit. Cables all looke good as I've traced them the entire length, including inside the salon cable tunnels (Man, is it tight underneath that flybridge!?!). Have checked the 12V power circuit and it has power. Autopilot works fine. Laptop chartware seems just peachy, but tells me it is getting no GPS signal. Radar functions perfectly (w/ exception that I get no course/speed readout anymore). As far as I can tell, this thing ought to work....But it doesn't. I am clearly getting no GPS signal output to the other devices. Does anybody have any expertise on these GPS units. Do they just go bad? How can I check? Owners' manual is of no use re troubleshooting. Thanks in advance.