| I don't know how the gea71 is put together but on some engine monitors the a2d circuits are not super well isolated from each other. ...so that if you have a short to ground on an adjacent channel you get weird results on other channels. Also, if the gea71 is doing the frequency to voltage conversion, then you have the wires all the way from the probe to the gea71 subject to RF interference.
It's possible neither of those are your problem but just sayin.... Alan, The fuel probe wires go directly into the G900 GEA71 module (connector P702). The G900 does the conversion that other use the Princeton box for. The left probe goes into pins 15 (white), 32 (blue), 75 (orange). The right probe goes into 15 (white), 12 (blue), and 74 (orange). I also have intermittent failures on my left probe. Haven’t hunted down the problem yet, because it only happens every few hours for a few seconds at a time, so it is hard to duplicate. I did have an entire flight where it went dead, but it immediately started working again on its own on the next flight. I have thought of switching the probe wires as they go into the G900 to determine if the problem is inside the GEA71 vs in the probe or the wiring, but that is a painful rewire to accomplish in my setup. From: Colyn Case [mailto:colyncase@earthlink.net]
Sent: Thursday, September 04, 2014 1:24 PM
Subject: Re: [LML] Right Fuel Tank Probe Alan, not sure how everybody else does it but mine comes in with the rest of wire bundle from the wing and has a 10-point princeton converter right there. I had flakiness like that which had to do with actually the old converter. When I put the new ones in, the problem disappeared. I'm not sure what your setup is but chances are the garmin 900 only understands a voltage value which means you have to have a converter in there somewhere. (converting frequency to 0-5V). On Sep 3, 2014, at 11:52 AM, Alan Crawford wrote: Need help ... Right fuel tank gauge is intermittent ... Where does the wiring come from the fuel tank probe to the Garmin 900 display? ... Looking for a loose connection! House is being remodeled and can't find my books or notes in storage?
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