M Terry Posted July 20, 2021 Report Share Posted July 20, 2021 On my F, the electric trim only works in the nose down direction. No movement or noise from the motor. The mechanical trim wheel works normally. I'm going to go looking for the flaw this week. Anyone else have this issue? Where is the first place to look? Quote Link to comment Share on other sites More sharing options...
warren.huisman Posted July 20, 2021 Report Share Posted July 20, 2021 Sounds like a broken wire somewhere. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
carusoam Posted July 21, 2021 Report Share Posted July 21, 2021 A good time to pull the CB on that until everything is better known… Nothing scarier than an AP that isn’t cooperating… Start with cleaning the electric switches… an MS standard maintenance step… Next step… add some detail about the switch… who built it, BK? Take a pic of the switch… if it is a Bk switch… there is plenty of answers posted around here… PP thoughts only… Best regards, -a- Quote Link to comment Share on other sites More sharing options...
David Lloyd Posted July 21, 2021 Report Share Posted July 21, 2021 I couldn't find a schematic for the trim circuit. Anyone? For now focus on the connections from the trim switch to the trim switch relay. Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted July 21, 2021 Report Share Posted July 21, 2021 If it is a Century trim, I would wiggle the wires by the disconnect relay. Could be the wiring just about anywhere. Quote Link to comment Share on other sites More sharing options...
warren.huisman Posted July 21, 2021 Report Share Posted July 21, 2021 I’ve had this issues a few times on my J. Twice it was a broken wire in the area of where the wire exits the yoke at the bottom and once a bad micro switch (1 of 3) in the trim switch itself. Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
neilpilot Posted July 21, 2021 Report Share Posted July 21, 2021 Not really on topic, but one of the most "exciting" post-maintenance flights was after a shop installed a rebuilt AP elevator servo. I failed to notice the problem during preflight, and proceeded to climb to about 3k and then engaged the sTec 60-2. When I engaged the altitude preselect to climb to 4k, the AP immediately entered a steep dive. I then disengaged, climbed to 4k, and with a 3k preselect the AP immediately began a steep climb. Turns out the servo was wired in reverse. My shop blamed sTec, and explained that the servo that's used in several different aircraft needs to be wired in reverse only for the Mooney installation. I blame the shop, and also my inadequate preflight. Quote Link to comment Share on other sites More sharing options...
Yetti Posted July 21, 2021 Report Share Posted July 21, 2021 Start with the simple things. Contact cleaner the switch and the limit switches. Then VOM and you will find it. Just for fun we would take a trailer light blub Cut an aligator clip in two and solder the ends to the bulb. Visual reference that one person can use. You can see it light up on the floor if you were in the cab. Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted July 21, 2021 Report Share Posted July 21, 2021 5 hours ago, David Lloyd said: I couldn't find a schematic for the trim circuit. Anyone? For now focus on the connections from the trim switch to the trim switch relay. I posted them here years ago. Go look in the download section. Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted July 21, 2021 Report Share Posted July 21, 2021 8 minutes ago, N201MKTurbo said: I posted them here years ago. Go look in the download section. I just looked and they weren't there, so I just uploaded them. 1 Quote Link to comment Share on other sites More sharing options...
Yetti Posted July 22, 2021 Report Share Posted July 22, 2021 Mooney F 70s schmatics.pdf I don't think the trim circuit is in here. But it does show a co pilot plug. Which is in my plane with nothing going to the yoke. Also the flap switch is different that what is in my plane. Mooney F 70s schmatics.pdf Quote Link to comment Share on other sites More sharing options...
M Terry Posted July 23, 2021 Author Report Share Posted July 23, 2021 the 2 short green wires that cross from lower pole to upper pole on the switches were both broken off. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted August 1, 2021 Report Share Posted August 1, 2021 Great follow-up with a pic, M T! Problem solved? Best regards, -a- Quote Link to comment Share on other sites More sharing options...
M Terry Posted August 6, 2021 Author Report Share Posted August 6, 2021 I'm just using the manual trim for now. When I have time to get a mechanic over I'll get them to repair the connection. 1 Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted August 7, 2021 Report Share Posted August 7, 2021 Might consider an Avionics shop, many A&P’s aren’t as adept with soldering as anAvionics tech. Quote Link to comment Share on other sites More sharing options...
flyboy0681 Posted August 7, 2021 Report Share Posted August 7, 2021 I won't recount the entire story now (it can be found somewhere here on MS), but about seven years ago I had a runaway trim situation that was scary has heck because I couldn't figure out what caused it. A few weeks later the same thing happened, this time I realized it occurred when using the trim switch. I eventually noticed that the nose down position was sticking, eventually resulting in my replacing the switch. Ever since that incident I keep my hand on the trim wheel making sure it stops. Quote Link to comment Share on other sites More sharing options...
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