Gear Up Alarm fail at annual

[TargetDriver]

12 hours ago, carusoam said:

That’s unique...

See if that shows up in the logs anywhere... somebody put a fair amount of effort in to mount that switch...

Those donuts are looking pretty fresh.... 

Best regards,

-a-

The schematic shows the airspeed safety switch right next to the gear over ride switch on the diagram in the  "upper panel" area which leads me to believe that it should be the version that you guys are talking about, on the back of the airspeed indicator.  I've scoured the prints for any indication of a similar switch on either wing section (mines on the left wing).

The logs say the donuts are 7 years old but I've measured them and the stance is still riding high so I haven't messed with them. 

[TargetDriver]

UPDATE !!!!!!!!!!!    HEY EVERYBODY, HAPPY FRIDAY !!!  The sun is shining again in the world of Mooney !!!   Can you guess why I'm so happy ????   FOUND IT !!!!!!!!!!!!!!    I quit last night at 10pm after a 12 hours day on it, in it, under it and inside it. 

Not sure how it all works but....  the ground wire from the gear warning horn goes through a large mating plug below the panel and after it comes down from the pilots left A post under the headliner. The ground wire pin had pulled out of the plug. Fixed the pin flare tabs and reinserted it. Tug tested good. 

Before that I had found that the power was back feeding from the Gear Over Ride switch on the WE31D22 wire (with the diode-it checked bad once I had cut that wire ahead of it and isolated it-replaced it with a new one).  maybe the lack of a ground did something to the diode? dunno.   Once I reconnected the ground wire I swung the gear and tried the throttle. Walaaaa, no buzzer noise off idle with the throttle !   Fixed. 

IA inspects it today, sign off logbooks, go flying this afternoon !!  IPC and Biannual later! 

Guys I can't thank you enough for all the technical help!!  Your suggestions helped me to know which wires to chase down and what to look for. NEVER could've done it without you !   We areplanning on going to the Kerrville hooah this year some hopefully I can meet some of you guys there, or at Oshkosh if I get to go, or... If you're close to Oklahoma City after August 1..relocating for work there.   ... I need a hanger there too !

[carusoam]

The power of MS is incredibly strong...

It is a community.

Best regards,

-a-

[thinwing]

You probably did as well trouble shooting this as anybody..congrats!..a word...say you had taken the problem to a MSC charging 120 HR.So 12 hrs ,most CP will squawk at paying 1400 to fix a simple loose connection.Also  nobody mentioned this about diodes,they are one way switches but at a cost...typically at least a 1 volt drop ,so they can act as resistors ,also depending on voltage applied ,can be switched off or on depending on voltage ,or proportional voltage.That is why they are called semiconductors.Another word about Mooneys multiplug under the panel ground connector.These are multiplugs grounding fuel pumps,avionics,lights,accessory..etc..they are secured with two knurled screw style nuts and I've never seen them safetied.When this unit loosened,all kinds of electrical failures occur.Sometimes resulting in component replacement of offending ground.(See keep swapping out components till it works mechanic physophy)For all you budding aircraft electrical experts working on 30/50 year connections..a hint..Stabilant 22....magic

 

[TargetDriver]

Thanks Thin...   Just tried to use basic troubleshooting on something I know very little about... probably more about intimidation than anything.  Could not have done it without the great help and guidance from the guys here on MS.  I'm not on any other forums and never really have been but this...is gold !

I looked up the Stabilant 22. Looks like great stuff. I will hit NAPA to see if they have it... Sure can't hurt to add to the chem shelf in the hanger.

R

[amillet]

You guys are amazing. My knowledge of electronics is not much more than don’t pee on the electric fence, learned on the 200 cow dairy farm on which I was raised 

[KB4]

On 5/31/2018 at 12:41 PM, jackn said:

The airspeed switch is attached to the back of the airspeed indicator. There is a procedure in the maintenance manual to check it. Essentially, you put a piece of surgical tubing on the pitot tube and roll it closed until the switch opens. I think it opens when The asi gets to about 65kts. 

Yes, Jack's correct.  I have a cotter pin at one end of the plastic tubing. (Lowes tubing), just roll it like tube of tooth paste that is almost gone, (You will see airspeed increase.) Keep folding and squeezing air in pitot and have someone else in plane take note of the speed where gear retracts.  My POH says 65k +/-  4k

[KB4]

On 5/31/2018 at 10:34 PM, TargetDriver said:

Airspeed switch- I got all the way under the panel and there is nothing attached to or coming off of the back of the airspeed indicator. It's back its basically flat with a small black plastic boss in the center with some wires that are heat shrinked together, possibly 3 or 4 wires.  Nothing to put a nipple or rubber surgical hose on to.

I have attached a pic of what I believe is the airspeed safety switch.  MS has rotated the pic 90 deg. Sorry.

Hose attaches to Pitot Static Tube to fool the plane into thinking it is flying and test the AS switch.

[Mike A]

Try twisting the throttle. Mine (1980 K) goes off periodically and a quick 1/4 to 1/8 twist of the throttle does the trick (it’s not a veneer type).