Tommy

Trim servo: http://youtu.be/eUksz4D2zX8 Pitch servo: http://youtu.be/WU03FT9J8OY

Ok I did the test on my KFC 200 (1981 M20J) today on the ground. I also put two go pro camera to film the servos. The test method: Pull the yoke to neutral, engage the autopilot with the alt mode off, use the pitch modifier to command UP, the FD bars show fly up and the yoke should move out, CWS, neutralize yoke, release CWS, pitch modifier down, FD down, yoke moves in, CWS, neutralize yoke, release CWS, ALT mode on, push yoke slowly ~3 second delay for trim to slowly start moving, pull yoke slowly, ~3 second delay for trim to move the other way. Observations 1) when test button is pressed - the trim warning doesn't flash at all. 2) the manual electric trim is working well - full range and reasonably fast (90seconds -clip 1). It disengage the A/P 3) The FD computer is commanding correctly 4) The pitch servo doesn't seem to be doing anything at all (the cable wheel doesn't seem to rotate). No matter what I do, it just sits stationary (see clip 2). The yoke doesn't move in or out when I engage FD/A/P (No alt mode) and then command pitch down / up using rocker switch. 5) when I engage FD/Alt/AP and push in the yoke, the trim wheel starts to move up in 3 seconds as it should but nothing happens when I pull the yoke back. The trim warning then flashes + sounds. My friend said he can hear the pitch servo clicks but no movement. I have cleaned the computer terminals and lub all the ball bearing. The cable tension seems ok. So is it conclusive that it is the pitch servo that's playing up? Before this I was getting frequently "trim warning" - can you get "trim" warning with a pitch servo problem or does it limit to trim servo only? Thanks, guys!

Is this KFC 200 you are referring to?

So just wondering how to test pitch and trim servo individually?

Do I need to hold onto the control wheel in order to trigger off auto trim when performing AP preflight test?

Hi Tomn. Resurrecting this topic as it seems like my 1981 J has exactly the same problem. Can I just ask: Where is the separate motor for manual eletric trim? How much time did it take to replace the trim servo? Thanks!

And I will be doing an actual flight test today

I measured the voltage across the wire - all of which are clearly labelled. If I swap the polarity then the horn went completely silent. The stall vane doesn't seem to be doing anything at all with or without avionics switch on. It all kind of started after a bit of rain two weeks ago. The stall warning started blaring pre flight then gone completely silent which was unusual. Before that the stall warning is working intermittently. I am just surprised to find one of the wire came off the stall warning. Forgot to mention the autopilot warning now is working! I am just hoping that after drying the stall warning vane with a bit of flying. Everything will be working again!

Yes sc628

Ok the polarity was correct (stall warning SC628) The voltage was 9 to 10 v when master is on - blaring Then dropped to 1 or 2 when avionics is on - silent I also replaced my autopilot one with a new sonalert and it too is blaring (my head hurts!!) when master is on then went reasonably quiet (but can still hear the horn warning) with radio master on. I haven't filed the bird yet so not sure how it all pans out...

Ok done a ground test with my KFC200 on a 1981 J. Time to dig your guys' brain! Observations 1) manual eletric trim (with yoke) works and will disengage ap 2) FD bar shows commanding aircraft pitch in the right direction when vertical pitch command is pressed on the Mode Panel (with and without AP AND with and without Alt engaged) BUT the trim wheel is not turning at all and the trim indicator shows no movement. 3) and when CWS is pressed the FD bar reset. 4) the red TRIM warning doesn't flash when "test" button is pressed. It used to but seems not any more in the last few flights which corresponds to the failure of alt/pitch control 5) the HDG hold worked perfectly This is in the context of perfectly working AP but with intermittent TRIM flashes and disengagement of AP (especially if it is quite out if trim) So is it my trim servo? Thanks guys!

My manual electric trim (on the yoke) seems to be functioning fine. But I don't think I have pitch control / alt hold ability with my KFC 200 A/P (I am going to do a thorough test on Saturday) Does it follow then that the problem is with the computer module not the trim servo motor???

Well it does the same thing with both new and old sonalert.

Hi guys! Here is another one for you intelligent good looking Mooniacs out there! My stall warning went completely silent recently so I replaced the sonalert (found one wire was detached from the sonalert!) and now it's blaring when with Master Switch (and continues even with CB pulled) and silent as soon as the Radio Power On? What does it mean?

Got it! And for those interested it's 14V on my system And I just discovered that my J comes with LOC and Glidescope!! Sweet~~ Now how do I use them?

Hi fellow Mooniacs! How do you guys ground test trim servo?

Forgot to mention, prior to this, the trim warning light will come on fairly frequently - especially if the aircraft is out of trim by a reasonable margin. Is this indicative of a trim servo problem? Ps. I had no issues using the manual electric trim.

Also, can anyone point to me the location of trim servo? Thanks guys!

Hi guys just wondering what would be the input voltage of the ks272 trim servo on a 1981 J (SN 24-1142) ? Thanks! Tommy

Thanks! PTK! Will do!

I don't think it's the CWS. Becuase my autopilot still holds HDG and will turn to new HDG bug. I thought it won't do that if you the CWS is engaged. Just wondering what would be the easiest and quickest test to differentiate the causes (ie. servo vs non servo) and just exactly what are the non- servo problems that can cause this symptom? Ie. no pitch command (assume FD didn't command at all when UP/DN switches are pressed with or without ALT Hold)? Thanks guys!

As far as I can tell, it looks like FD isn't commanding any pitch change. What does it mean? The whole system was working perfectly fine three weeks ago.

Yo fellow Mooniacs! When I first got my M20J (1981) the autopilot (KFC200) HDG and Alt Hold are both working beautifully. Lately I have noticed that the alt hold - the HDG is working perfectly - isn't working any more for reasons unknown (I never abused the system and all indications are normal). It doesn't hold and when I press UP/DWN rocker switches (with or without Alt Hold mode on), the auto pilot does nothing. Does anyone know what would've caused this? Is there anyway to reset Autopilot KFC 200? Thanks! Tommy

Hi guys! I have a 1981 J with KFC 200 installed. Just wondering what is the best and quickest way of changing and then holding the changed altitude? For example I was crushing at 7500 feet yesterday and the ATC asked me to decend then hold at 5500. If I had HDG and Alt on at the time with cruise power. What should I do to quickly ask the Autopilot to decend and hold at 5500 or vice versa? Cheers Tommy

So it means you can't use MGL on a Mooney? What happen if you do?