Several weeks ago I turned my master switch on to check my tach time and had red X's all over my G3X. Really spooky since my last flight included some IFR.
Thanks to the G3Xpert (Great help by the way), he pointed me to a CanBus shorting out somewhere. Pretty easy to track down to the connector on the back of the MFD by wiggling the wires. Nothing jumped out at me as shorting out when I took the connector apart, except for the 4 into 1 solder connection that was underneath the clamp bar strain relief on the connector.
I couldn't get the fault to repeat itself without the clamp bar on the connector, the solder connection was heat shrunk as well as bundled with several other wires and silicone taped prior to clamping. Pretty easy to see the indention of the solder connection underneath the clamp bar, it was about the size of a popcorn kernel.
I was also confused by the 4 CanBus wires spliced together at the MFD, my wiring diagram looked like this:
I had the original G3X harness made for me and added the rest of the equipment later. Garmin also revised their wiring recommendations on the CanBus, used to be able to have nodes something like 3 feet in length. When I added onto the CanBus adding the other equipment reference the wiring diagram I left the node to the GAD29 floating and daisychained the rest of the equipment starting at the GSU25 where the old termination was. Well the actual wiring had 4 nodes from the MFD, 1 to the PFD, GSU25I, GEA24 and the GAD29.
I cut the 4 way CanBus splice out and wired the CanBus per current recommendations without any nodes and used longer pigtails on the solder joints to place them aft of the connector and bending point of the wiring. So Far so good. I hope this fixes it.
My wiring diagrams though not 100 percent correct were very essential to tackling this problem, also make sure your solder joints aren't being clamped by the strain relief.
The G3Xpert also cued me to the backup RS-232 link from the GSU25 to the PFD so I won't lose my Primary flight instruments in case my CanBus goes down again.
Thanks to the G3Xpert (Great help by the way), he pointed me to a CanBus shorting out somewhere. Pretty easy to track down to the connector on the back of the MFD by wiggling the wires. Nothing jumped out at me as shorting out when I took the connector apart, except for the 4 into 1 solder connection that was underneath the clamp bar strain relief on the connector.
I couldn't get the fault to repeat itself without the clamp bar on the connector, the solder connection was heat shrunk as well as bundled with several other wires and silicone taped prior to clamping. Pretty easy to see the indention of the solder connection underneath the clamp bar, it was about the size of a popcorn kernel.
I was also confused by the 4 CanBus wires spliced together at the MFD, my wiring diagram looked like this:
I had the original G3X harness made for me and added the rest of the equipment later. Garmin also revised their wiring recommendations on the CanBus, used to be able to have nodes something like 3 feet in length. When I added onto the CanBus adding the other equipment reference the wiring diagram I left the node to the GAD29 floating and daisychained the rest of the equipment starting at the GSU25 where the old termination was. Well the actual wiring had 4 nodes from the MFD, 1 to the PFD, GSU25I, GEA24 and the GAD29.
I cut the 4 way CanBus splice out and wired the CanBus per current recommendations without any nodes and used longer pigtails on the solder joints to place them aft of the connector and bending point of the wiring. So Far so good. I hope this fixes it.
My wiring diagrams though not 100 percent correct were very essential to tackling this problem, also make sure your solder joints aren't being clamped by the strain relief.
The G3Xpert also cued me to the backup RS-232 link from the GSU25 to the PFD so I won't lose my Primary flight instruments in case my CanBus goes down again.
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