Tach failure modes

[recapen]

Was out flying around on Sunday - my tach started going up and down inconsistently...then it went to zero.

Fuel flow and other indications were normal...more importantly, I was close to homeplate. It didn't come back after landing and rollout so I don't think it is a loose wire.....

I have ordered a new tach sender after visually looking at the wiring - looks OK.

I'll be changing the oil a couple of hours early this cycle - I think the tach sender is hidden next to the oil filter on my 6A's XPIO360B1F6.

Anyone else have a failure mode like this one? What was the eventual cause?

Thanks,
Ralph

[Rob Hickman]

Check the fast on terminals and make sure the sensor has not come out of the machined red housing.

[recapen]

I am using a three pin Molex crimped and soldered - it was intact.
The sensor however looks like whatever glue lifted and appeared to be coming out of the machined housing as you indicated.

Replacement unit installed - all is well with the tach.

THANKS!

[Oly148]

I have an AFS 5500 EFIS with the tach sender attached to the side of the left Slick mag. This Saturday I had the same symptoms as the guy in the first post. I removed the tach sender and found the sensor is partially separated from the red plug that is attached to the mag. I have the internal EMS board.

This tach sender does not look like the ones available on Acft Spruce, Stein Air, UMA etc. Does AFS sell these and how much are they?

[Jonathon]

That is one of ours. We are out of stock at the moment and it could be a minute before we can get another batch of these sensors made. Since you clearly need more immediate service, The UMA T1A9 for Slick will work:
https://www.aircraftspruce.com/catal...endingUnit.php

[Oly148]

Thanks Jonathon- it looks like there is a shielded wire on that one which I assume is the ground wire. My current sender has no shielded wires so can I just snip off the shielding off the wire when I crimp on the spade connectors?

[recapen]

Pretty much identical to what I found!

Thanks for posting an alternative source...