I've got a small boat loran set (it's a King 8002 aero/marine unit) that I'm trying to get working. It was working fine when it went on the shelf in my closet 5 yrs ago. When put on a 12vdc bench power supply, it powers up, gives an initial opening screen with numbers, but doesn't go any further, and doesn't respond to any key pushes.
Seems somewhere I heard these things have an internal battery. If it does, the internal battery could certainly be bad by now, as the battery goes back awhile before the set went on the shelf.
If the internal battery is dead, would that keep it from working, even though it's powered up with 12v? Also, do these units have an internal battery, or is that just my imagination? I don't have a manual for it, so can't get an answer there.