GTN 650 - radio needs service?

bflynn

Final Approach
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Brian Flynn
Getting a message on a 650 which just says “radio needs service”. The unit has effectively disabled the radio - you cannot tune a new frequency and cannot swap.

has anyone seen this before? What kind of service might it need?
 
Before you go too far, make sure it’s not the circuit breaker, which can fail by having a large voltage drop. I had this problem, you will need to check the voltage on the radio side and with the unit
ON.
 
If I remember correctly the gtn650 has at least 2 discreet power wires to the harness.
 
Hopefully it's simple, thank you for the advice.

I didn't notice a blown circuit, but I could have missed it. Yesterday....was not my best flight.
 
Hopefully it's simple, thank you for the advice.

I didn't notice a blown circuit, but I could have missed it. Yesterday....was not my best flight.
I don't think he's suggest the CB tripped, but rather failed internally, reducing the voltage output, not completely shutting off the circuit but not providing full voltage.
 
Getting a message on a 650 which just says “radio needs service”. The unit has effectively disabled the radio - you cannot tune a new frequency and cannot swap.

has anyone seen this before? What kind of service might it need?

Is it still under warranty? I'm guessing its getting pretty close to the end of warranty for the last straight 650s made, which I think is 24 months. I'd get that damn thing out and sent in if still under warranty.
 
I don't think he's suggest the CB tripped, but rather failed internally, reducing the voltage output, not completely shutting off the circuit but not providing full voltage.

Correct.
 
That's an unlikely breaker failure mode. A breaker will usually either trip or weld itself shut.
 
Not a 650 expert by any means, but I'd guess the internal micro-computer is FUBAR . Agree that CB failure is not likely but OTOH this is an easy thing to check. Put the voltmeter probe on the wire harness ring terminal, NOT the CB terminal or screw so you are checking for poor terminal contact/corrosion also.
 
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