Faulty fuel flow sender FT-60 Red Cube

Fixing a Faulty fuel flow sender FT-60 Red Cube

Hi Guys,

My FT-60 has been failing for the last two weeks, total installed and flying time 630 hours, initially it started not providing an output to my Skyview display and I though that I must have had a bad crimp connection, so I checked this by re-crimping the the 3 wires that connect the FT-60 to the Skyview. Went for a fly and all seemed good, the next week while flying it again failed, so having ensured that the wiring was OK the next culprit was the FT-60.

I removed the FT-60 from my RV7 and opened the access cover to the side with the control board, he screws are held in place with thread lock but came out easily enough,

The board is covered with some rubber sealant which I was easily able to remove with a jewelers screw driver.

This revealed the circuit board and it was immediately apparent what the problem was, the chip that is sitting on the edge of the FT-60 in the photo was loose, when I pressed down on it, it came away from the board.



I do not have the tools to work in a confined space such as this so I pretty much gave up at this point and ordered a new unit.

By chance I sent this photo to Glen an RV friend of mine who immediately said I have a friend who can fix this.

Below is the email response from Glen to me this morning;

Hi Eddie, a quick visit to Ron was as educational as ever. When I described the part that fell off the board, he said, "Yep, that'll be a 2903 comparator. I'll just put a new one on."

So, lay the original on his flatbed scanner, scan at 4800 dpi and enlarge so he can read the lettering. Yep, that's what it is all right. In goes a new one. He uses flux from a syringe, and a fine iron rather than re-flow. While in there, he redid a couple of other dodgy joints.

Hook up some power, and look at the output on the scope. Blow through it, and lots of lovely square waves ensue. Score!

Rather than use potting compound, he sprayed it with a lacquer which will protect and secure it. All you need is some suitable gasket compound to seal under the hatch. It may not even need thread lock on the screws as they are a bit tight anyway. Also some form of gumbo around the wire where it enters, as you already spotted.

Awesome, thanks soooo much Glen and Ron.

I have cancelled my Spruce order and will re-install this Saturday.

Cheers

Repair of Red Cube FT-60

Hi Guys,

I got this response form Dave at EI which is more than I had hoped for after this length of time;

As the transducer is not designed to be disassembled, I am not aware of this type of failure. If you would like, I can create a return authorization number for you to reference when returning the transducer for evaluation. I'm sure our production manager would like to have a look at it. If you would like to do so, please provide your shipping address and phone number. As you have already purchased a replacement, I'm not sure it would be of any use to you, but we would typically offer your a 1/2 price replacement having evaluated the transducer and determined the nature of its failure.
Please let me know how you would like to proceed.

And after sending him the photo of the unit and repair info;

Thank you for your detailed repair information. Please note, E.I. does not advocate or warranty any repairs done outside our facility. As previously stated, our fuel flow transducers are purposely built as to discourage any attempts to disassemble them. Per our fuel flow transducer's installation manual, "DO NOT attempt to remove the screws in this transducer because doing so will cause the screws to break and render the FT-60 UNSAFE".
If I can be of any further assistance, please do not hesitate to contact me.

Thank you,

Dave Arata
Sales & Tech Support