Fuel "Control monitor" or "Signal conditioner"

[edasmus]

The signal conditioner arrived today and I promptly went out to the hanger to hook it up. It PROMPTLY failed. My IA got the same intermittent behavior on the gauges by wiggling the 9 pin plug that is attached to the signal conditioner. Aero-Mach is sending an overhauled unit tomorrow to see if I get the same behavior with that one. This is fun.

[Ernie Martin]

I was kind of unhappy when I gave up on the system and now rely on fueling supervision, visual confirmation and time. After hearing what you're going through -- no longer unhappy.

Ernie

[edasmus]

hahahahaha.....Thanks Ernie, that was funny!

[edasmus]

I received the over-hauled signal conditioner on Friday and plugged it in today (Monday). It has the same erratic behavior as my original one.

[edasmus]

Does anybody know what it means, as far as the fuel gauges are concerned, when turning the master switch on causes the gauges to indicate negative or in other words, below empty. When the gauges work, they work fine. When they don't, they indicate below empty. If you turn the master switch off when the gauges are indicating negative, they rise slightly and indicate empty. When the master switch is turned on and the gauges are not working, they get "sucked" below empty. It is probably a short somewhere. Anybody have any theories?

[Pete Somers]

OK Dave.

1. Was thew plug replaced on the signal conditioner?

2. Inspect the plug on the back of the instrument cluster, that does mean removing the plug and checking it.

3. Has your engineers got the proper test box for this system, if not it will make fault finding almost impossible.

I keep on about having a test box for this system, however you choose to ignore me, you cannot maintain the capacitance system without it. I have kept quiet for a while on this one as I just wanted to see what other owners do, and it does seem to me 'not a lot' perhaps you will listen now.

As regard the test box, Cessna made one years ago to cover all the aircraft with this system, this included all the connectors for the signal conditioners. Bendix did one as well and you could use the Cessna connecters.

Let me know how you get on

Pete

[edasmus]

Pete,

I am printing your response and taking it to my shop. You cannot believe how frustrated I am over this issue. This is one of those times when I am simply trusting the people who supposedly know how to fix airplanes. I am an air traffic controller not an electrical tech or maintenance tech. If these people can't fix it, then I lose! Simple as that.

Ed