Ed Cesnalis Posted October 11, 2016 Report Share Posted October 11, 2016 What is this noise? How can I troubleshoot? It sounds and acts a lot like a cooling fan. I have a muffin fan that is very loud and the noise is similar. Symptoms: Noise begins during flight and is not heard until throttled back for landing. Sounds like loud cooling fan. Master Avionics Switch (This switch turns on 3 of my 4 radios) turns the noise off but it won't turn it back on. All 3 radios on this switch can be turned off and the noise remains All circuit breakers can be popped and all components turned off/dark and the noise remains. With headsets on it sounds like radio noise but take them off and its a loud whine loud over the engine at idle or taxi. I stopped flying because there are not landing opportunities where I fly and I haven't a clue what I'm dealing with. ???????????????????? Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted October 11, 2016 Author Report Share Posted October 11, 2016 Yes it does have an avionics cooling fan and yes that is what this noise sounds like. My avionics cooling fan has its own switch, this noise is from something else. Link to comment Share on other sites More sharing options...
Tom Baker Posted October 11, 2016 Report Share Posted October 11, 2016 Try popping individual circuit breakers. To isolate the circuit it is on, then trace the wiring. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted October 11, 2016 Author Report Share Posted October 11, 2016 Try popping individual circuit breakers. To isolate the circuit it is on, then trace the wiring. I can pop every single breaker and the noise continues. If I do a wire trace it will have to be from the Avionics Master Switch that turns off 3 radios plus this mystery noise. There are things not on a breaker like my muffin fan, a network router (unless its powered by a component that is on a breaker) and the mystery item. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted October 11, 2016 Author Report Share Posted October 11, 2016 I guess we need to trace the wiring from the avionics master switch and see what it powers. If it only powers those 3 radios and they are not the source of the noise maybe its from the charging system? Maybe turning of the Avionics Master Switch reduces load and changes the state of the charging system and the whine stops??? Link to comment Share on other sites More sharing options...
Tom Baker Posted October 11, 2016 Report Share Posted October 11, 2016 I know your airplane is an odd duck, but all the CT's I have ever seen have individual breakers for the radios controlled by the avionics master switch. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted October 11, 2016 Author Report Share Posted October 11, 2016 I know your airplane is an odd duck, but all the CT's I have ever seen have individual breakers for the radios controlled by the avionics master switch. Mine does as well, I can turn off all the radios one at a time with the breakers. Once they are all off the noise remains until I turn off the Avionics Master Switch. Circuit breakers are no help in troubleshooting this. Link to comment Share on other sites More sharing options...
Tom Baker Posted October 12, 2016 Report Share Posted October 12, 2016 Mine does as well, I can turn off all the radios one at a time with the breakers. Once they are all off the noise remains until I turn off the Avionics Master Switch. Circuit breakers are no help in troubleshooting this. To me it sounds like they were more help than you realize by eliminating all those as a source of the problem. Link to comment Share on other sites More sharing options...
Anticept Posted October 12, 2016 Report Share Posted October 12, 2016 Check intercomm by turning it off. If it's a PM3000, it's sensitive to noise. Your capacitor might also be going bad. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted October 12, 2016 Author Report Share Posted October 12, 2016 I did check the intercom too. Just thought of a plan, go flying tomorrow and when I come back I will turn my radios off with the circuit breakers and leave the master switches and avionics master on when I turn the ignition off. This should leave the noise going with the engine/prop stopped so I can snoop around and find the source. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted October 12, 2016 Author Report Share Posted October 12, 2016 it took 1 second to find by shutting down with master switches left on. Zaon PCAS screaming like a Banshee. Link to comment Share on other sites More sharing options...
rhanson Posted October 13, 2016 Report Share Posted October 13, 2016 CT, Are you referring to an XRX malfunction, or an impending collision ? Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted October 13, 2016 Author Report Share Posted October 13, 2016 XRX malfunction Link to comment Share on other sites More sharing options...
gbigs Posted October 13, 2016 Report Share Posted October 13, 2016 XRX malfunction We had a buzzing noise in headsets for a year before Lone Mountain took the avionics apart and found a ton of problems in the installation. In essence it turned out to be small shorts in the wiring due to poor connections and a melted wire. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted October 13, 2016 Author Report Share Posted October 13, 2016 I'm thinking that this Zaon unit could start a fire based on the amount of noise it can make. Why didn't old FDwest put it on its own breaker? If it had its own breaker the noise would never have been a mystery. Link to comment Share on other sites More sharing options...
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