G1000/S-Tec 55X Electrim Trim Issue

[jfdez]

So, at a loss here. Apparantly there is a fuse in the S-Tec box that keeps blowing when electric trim is in use by the autopilot. This makes the electric trim inop. Everything else works correctly i.e., trim servo, autopilot etc. Except, that once the fuse blows, only manual elevator tim is available. Avionics shop finds no shorts anywhere and no electrical faults on the trim servo. S-Tec's answer was to "loosen" elevator control cables, which does not make any sense in any Mooney! Any thoughts here? Thanks!!

[kortopates]

I think the Mooney equivalent is to ensure the trim system, especially cockpit wheel chain, are well lubricated such that the manual trim moves very easily for you to ensure the servo is not meeting resistance/strain to pop its breaker/fuse. There also could still be an issue in a weak connection or ground leading to excessive current drain.

[jfdez]

Makes sense, we will give that a try. Thanks

[Awful_Charlie]

If the install is similar to the KFC150, then the trim servo is in the back behind the avionics bay, and the trim motor drives the trim rod with a small chain too. As Paul says, make sure you can run the trim easily by hand, if you can't there are a number of universal joints as well as the screw assembly in the tail to check for lube, damage, or foreign matter, and then the trim wheel chain and gearbox too. If you get the bottom panels off, check for trim tube scoring whilst you are there - there is an SB or SI for it