Furuno Radar Question--Fatigue?

[Kings Gambit]

I have a Furuno Model 1622 that's between 13 and 18 years old. When first "asked" to transmit after the 30 sec warm up period I get decent target strength on the return. But after a few minutes there is either no, or very weak, return even if I'm sitting the same place, such as at anchor. It appears to be "fatiguing out" somehow. Does anyone know about this or how to fix it? I fear a full replacement might be in the offing. But, I do not use it that much--I just need it when I need it, etc.

 

[Rick D]

Magnatron? Perhaps. I'm sure you already checked connections and current. I once had to replace a magnatron (sp) at Maritime Communications in MdR.

 

[capta]

I'd call a big ship electronics repair company and ask their techs about it. Any tech worth his salt should know this right off the top of their head. Those guys are repairmen, not parts changers and like a good doctor, they understand the symptoms.

 

[Kings Gambit]

Magnatron? Perhaps. I'm sure you already checked connections and current. I once had to replace a magnatron (sp) at Maritime Communications in MdR.

Yeah; the specs say the magnetron has a useful life of 500 hr including the hours on stand-by. The unit is probably 17 year old. If I average 40 days sailing days/year x 17 years = 680 sailing days (SD). Divide 500 hr/680 SD you get an average of 0.73 hr/SD of use to make 500 hr on the magentron. Of course, some days the unit would be on for several hours; others not at all. But the point is that the 500 hr would be easy to make in 17 yr for boat that goes out regularly and uses its radar. A symptom in addition to one the I mention above that I've also noticed, from the manual, is: "When the magnetron has expired distant targets cannot be seen on the display." The replacement magnetron is about $465 . At least it's not BOAT; it's only BOA(1/2)T!