Radar Voltage/Current

[osprey]

Hi, About three weeks ago I was out on the boat and turned on my Garmin chart plotter and it gave me an error code "Error code 2 Radar needs repair" (Garmin GMR18HD about five years old) I searched the internet and finally came onto a site which said that error code 2 is that the Magnetron heater is either over current or under current. I then contacted Garmin, who told me to send the unit in for repair. Problem is that I am in south east Asia. All Garmin websites refer you back to the USA when you click on support. I checked all the connections and found all to be OK. while I had the ray dome off I opened it up and had a look, all looked brand new. I re-installed the ray dome in hopes it had repaired itself (it had not) I removed the radar for the second time and ran through the wiring once more, and again found there to be 12.3 volts all the way to the power plug on the ray-dome connector. Then I had a great idea, I was using a digital multimeter, so decided to make up a 12 volt test lamp to simulate a load. When I plugged it into the connector at the ray-dome and then tested again, I found only 9.7 volts. I traced it back to the main power panel for the electronics and found the ground wire terminal to have a bad (corroded) crimp. Replaced terminal and re-installed radar. All works now. This is not the first time I have been led astray by a digital multimeter, in the not to distant past I was using the ohmmeter function which showed positive results which got me going in circles until I put on some sort of load. Volts are great, but current is what makes electricity work. My boat always keeps me thinking, I will endeavor to learn more.

Take care all, Pete

[Boatsb]

That's why we always test with load. I've found breakers that had bad contacts causing the drop too.