Moonbat Posted March 29, 2020 Report Share Posted March 29, 2020 This happens consistently every time for the last couple of months. When I raise/retract the gear during take-off, moving the J-bar from vertical to horizontal on the floor, the alarm horn begins to sound. I can make it stop it by gently pushing up with my finger the little metal arm in the now vacant capture collar on the bottom of the panel where the J-bar goes when the gear is lowered. Generally the noise persists until I level off. When I level off, I pull the throttle way back to 12-13” ever so briefly, the horn stops. Then I go back to a normal setting (20” or more) for cruise, and the horn never is a problem again for the rest of the flight. Is there a “throttle sensor relay” or the like that is failing? If so, where exactly is it located? ( I’ve got to solve this one, as it is very loud and annoying and really bothers any passengers.) Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted March 29, 2020 Report Share Posted March 29, 2020 I would start by lubricating the micro switch in the hole. You will need to do it on jacks or in flight... Quote Link to comment Share on other sites More sharing options...
Moonbat Posted March 29, 2020 Author Report Share Posted March 29, 2020 The microswitch in the hole is exquisitely responsive. The slightest touch upward, horn stops. Let it down, horn starts. What stops the horn is pulling back the throttle... way back to 12” or 13” . That is why I am asking, is there another microswitch “looking” at the throttle position somewhere / somehow? Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted March 29, 2020 Report Share Posted March 29, 2020 Yes, there is a switch on the throttle cable. Quote Link to comment Share on other sites More sharing options...
Moonbat Posted March 29, 2020 Author Report Share Posted March 29, 2020 Aha! Thanks. Is it usually behind the panel or somewhere in the engine compartment? What does it look like? Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
markgrue Posted March 29, 2020 Report Share Posted March 29, 2020 It is behind the panel on the solid part of the throttle cable where it transitions to the cable part. It might take a mirror to see it. Sounds like it is sticking. Mark Quote Link to comment Share on other sites More sharing options...
chriscalandro Posted March 29, 2020 Report Share Posted March 29, 2020 I’ll pm you. Quote Link to comment Share on other sites More sharing options...
Moonbat Posted March 29, 2020 Author Report Share Posted March 29, 2020 If the alarm circuit was working correctly, what is the condition about which the circuit and alarm are trying to warn me? Is it trying to warn me when there is a low power setting AND the gear is up / retracted / J- bar on the floor in the horizontal position? If so, and there’s a high power setting, i.e. throttle pushed well in, the throttle microswitch should be OPEN, so as not to ground the alarm buzzer, right? I think once I understand the “logic” the circuit is trying to implement, I’ll be able to trouble shoot it. Quote Link to comment Share on other sites More sharing options...
KB4 Posted March 29, 2020 Report Share Posted March 29, 2020 Spray electrical contact cleaner in the micro switch attached to throttle. I wiggled under and sprayed liberally exercise the switch. Quote Link to comment Share on other sites More sharing options...
tmo Posted March 29, 2020 Report Share Posted March 29, 2020 3 hours ago, chriscalandro said: I’ll pm you. If he doesn't know you PMed him, he doesn't deserve the honor... </s> Quote Link to comment Share on other sites More sharing options...
tmo Posted March 29, 2020 Report Share Posted March 29, 2020 Will increasing airspeed in the climb silence the buzzer? IOW, is the alarm perhaps triggered not by throttle position, but by airspeed (which might be read wrong, triggering the false alarm)? If you don't have airspeed sensing, then the squat switch that detects weight on the wheels serves the same function, check that. Quote Link to comment Share on other sites More sharing options...
chriscalandro Posted March 29, 2020 Report Share Posted March 29, 2020 1 hour ago, tmo said: If he doesn't know you PMed him, he doesn't deserve the honor... </s> I’ll pm you 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted March 29, 2020 Report Share Posted March 29, 2020 Two switches in the simple system... One in the Jbar hole... Other in the Throttle behind the panel... If the gear isn’t sensed as being down... then the throttle gets pulled out... the two switches complete the circuit... to sound the horn... Now... gear is up, and throttle is in... the plane is flying... while the horn is sounding... Expect the throttle switch isn’t behaving properly... it is acting as if the throttle is pulled out still... when you poke the switch in the Jbar hole... it is confirming the gear down... so... it goes silent again... Sounds like two things are pointing to the switch on the throttle... There are lots of pics of that switch and it’s adjustment around here... PP thoughts only, not a mechanic... best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted March 30, 2020 Report Share Posted March 30, 2020 7 hours ago, tmo said: Will increasing airspeed in the climb silence the buzzer? IOW, is the alarm perhaps triggered not by throttle position, but by airspeed (which might be read wrong, triggering the false alarm)? If you don't have airspeed sensing, then the squat switch that detects weight on the wheels serves the same function, check that. Manual gear Mooneys have 2 switches in the gear system. One on the throttle cable set to around 11-12”Hg, the second is on the gear down latch at the base of the instrument panel to say that the handle is latched. Clarence Quote Link to comment Share on other sites More sharing options...
Moonbat Posted April 1, 2020 Author Report Share Posted April 1, 2020 I was able to crawl upside down under the panel to find, loosen, slightly re-position ever-so-slightly closer to the shaft of the throttle cable, and then re-tighten the position mounting screws for the switch. I now understand EXACTLY how this thing works. I could hear the micro-switch make and break contact each time. Flight tested it today, too - a very nice but cold day - and when I tucked the gear into the wheel wells after take-off, a blissful, horn-free, silence followed - except for the sound of Casper's engine carrying me higher and higher. Success! 2 Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 1, 2020 Report Share Posted April 1, 2020 Great follow-up bat! Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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