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Electric Flaps Troubleshooting


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Can someone make sense of this schematic? Just as a quick recap, the flaps go down without an issue. They won't retract to either position or full up consistently (I have detents for t/o and full positions). If I leave the flap switch up and reset the breaker a few times, they will retract. I'm thinking relays or breaker. Thoughts?

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Do you have a helper who can tap the relays while you move the flap selector in the cockpit?  You might get an indication of a relay with dirty points.

 

Actually, after spraying everything done with electronic cleaner last weekend, and spraying the contacts afterwards with silicone, they began working normally. Not trusting them at this point, but at least headed in the right direction.

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Both relays have to actuate for up or down to work.  See how the red and black come out of the R and L relays.  (does not mean that all the contacts in the relay are working)  The bottom part of the circuit is the position indicator. 

The best way to see what is not working is with a VOM and a alligator clip on the negative lead.  Clip the neg to a good ground.   Get it into a non working condition then see where power is not flowing. 

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Hi Marauder,

can you add the traces that are really light?  I can't see the four traces clearly on the right in the photo. Also pencil in the pos and neg.  get a close up of the relay on the schematic.  Do you have another set of hands?  You can have someone put one finger on each relay and the other cycle the flaps switch.  Both relays must cycle. I still think the up limit switch may be the problem. With power off flaps down put an alligator clip on the up limit switch DVM on ohms or continuity(sound). cycle he up limit switch and the DVM will tell you if it's opening and closing.  I hope this is helpful I am sure you are frustrated. 

Jim

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Hi Marauder,

can you add the traces that are really light?  I can't see the four traces clearly on the right in the photo. Also pencil in the pos and neg.  get a close up of the relay on the schematic.  Do you have another set of hands?  You can have someone put one finger on each relay and the other cycle the flaps switch.  Both relays must cycle. I still think the up limit switch may be the problem. With power off flaps down put an alligator clip on the up limit switch DVM on ohms or continuity(sound). cycle he up limit switch and the DVM will tell you if it's opening and closing.  I hope this is helpful I am sure you are frustrated. 

Jim

This is the best I could do. The two most right lines are missing on my schematic. I drew them in based on where they look like they were headed. Does anyone have the schematic for M20F serial numbers 22-1273 through 22-1305?

I have the F and early J schematics but it looks like these serial numbers are the only ones with this detent setup.

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Hi Marauder,

i am still having trouble understanding the relays. A better close up of just the relay or a pic of the schematic on the side of the relay. It would also be helpful to understand where flap switch portion. I hope you understand I am not being difficult it is just really hard to grasp with out tracing from the start( Pos wire at the flap switch). 

That said of the five wires I think #4 wire is flaps takeoff down, #2 is flaps full down, #1 is flaps up to takeoff, and #3 is flaps full up.   #5 is ground. You can see power goes to flaps up to takeoff switch then connects to flaps full up switch.  So if the flaps don't go up at all when selected it's the up limit switch, the relay, or the wireing.

So use your DVM and follow the 12volts through the flap up switch and to the R relay. 

The relays I don't fully understand because I can't see all of the terminals. It looks like they swaps the polarity to reverse the motor direction. Down then swap to up. 

I hope this helps. It is amazingly difficult to troulbleshoot from a distance. 

Regards 

jim

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Hi Marauder,

i am still having trouble understanding the relays. A better close up of just the relay or a pic of the schematic on the side of the relay. It would also be helpful to understand where flap switch portion. I hope you understand I am not being difficult it is just really hard to grasp with out tracing from the start( Pos wire at the flap switch). 

That said of the five wires I think #4 wire is flaps takeoff down, #2 is flaps full down, #1 is flaps up to takeoff, and #3 is flaps full up.   #5 is ground. You can see power goes to flaps up to takeoff switch then connects to flaps full up switch.  So if the flaps don't go up at all when selected it's the up limit switch, the relay, or the wireing.

So use your DVM and follow the 12volts through the flap up switch and to the R relay. 

The relays I don't fully understand because I can't see all of the terminals. It looks like they swaps the polarity to reverse the motor direction. Down then swap to up. 

I hope this helps. It is amazingly difficult to troulbleshoot from a distance. 

Regards 

jim

I appreciate the help Jim. I work with a bunch of EEs and hope one of them can look at the actual schematic and see if they can figure out how everything works.

There is definitely a wiring schematic on the side of the relay. I'll see if I can get a picture of them.

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So because flaps are Not coming up = the R Relay(top one) The Top right pin of the R relay should have 12volts on it.   Follow that down and the "UP Limit Lower on Shaft" limit switch and the "take off UP limit switch"  are the places to start checking.  the part of the drawing that is missing is the Flaps switch which is off the bottom of the page.

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Have you tried to build a logic chart for what happens each time the flap selector switch is moved?

Starting with...

1) Flaps up to flaps T/O. What limit switches are closed. What opens and closes initially.  What limit switch is reached. What opens and closes at the end of the step.

2) Flaps T/O to flaps down. Same analysis as step 1)

3) Flaps up to flaps down  (on Neo post modern Mooneys)

4) Flaps down to flaps T/O

5) Flaps T/O to flaps up

6) Flaps down to flaps up (on Neo post modern Mooneys)

Which relays are activated, until which limit is reached.

Seems a little like complex digital logic using analog devices.

From the drawing there are five relays.

From the drawing there are four limit switches

Up limit, Down limit, T/O position (when going up), T/O position (when going down) (funky to explain)

Going through the number of relays and limits switches, and comparing to the six options above, you will probably find what is not operating properly.  Part of the challenge is the direction the switch is moving and where it is moving from.

I am only guessing.  But, I would look at this challenge using a logic chart.

Best regards,

-a-

 

 

Edited by carusoam
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Appending to the above list...

What type of flap switch do you have?

The drawing is only indicating two positions up vs down, with the possibility of a central neutral position.

Activating the switch sets everything in motion until the next limit state is reached.  The act of moving the switch up will power the motors going upwards. Moving the switch down should activate (possibly) a relay for reversing the polarity of the power supplied to the other five relays...

The post Neo modern Mooneys have a three position switch to include Up, T/O, Landing.  The same limits are used.  But it allows to go from flaps down to flaps fully retracted with one movement of the switch.  Really nice to have during the go-around, when everything is working.:)

In building the logic chart it may be helpful to know NC=Normally closed, NO=Normally open.

Hope all this logic helps to better understand the flap positioning challenge.

this is an extension of my guessing above...

Best regards,

-a-

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Another way would be to put it into fault condition then use test lead to complete the circuit with a test lead or wire across the limit switchs.  When it moves you found the offending limit switch.  It would be possible the switch attached to the flap lever could be going bad.  Check that first.  Probably 12v to the center.

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Another way would be to put it into fault condition then use test lead to complete the circuit with a test lead or wire across the limit switchs.  When it moves you found the offending limit switch. 

Depends on the type of switch, as mention above NO or NC, if NO then instead of completing the circuit, you would need to break the circuit.

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Would the parts catalog have what you are looking for?

best regards,

-a-

Nope. I need to know how the electrons flow. The flap switch is unique in the 1975 models. It is the only version that use the detent preselect flap function. It has unique switches and my paper schematic is smudged at the perfectly wrong spot.

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Does anyone have an electronic copy of the schematic labeled: SC1-800269L-1? My purchased version from Mooney was cut into 4 pages that seems to be missing an important piece for me -- the stupid flap switch.

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Pretty please!

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Actually, after spraying everything done with electronic cleaner last weekend, and spraying the contacts afterwards with silicone, they began working normally. Not trusting them at this point, but at least headed in the right direction.

 

 

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has the problem recurred since cleaning the contacts perhaps that's all that was needed

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You could try rearranging your switches and see if the problem changes.

I would, but since it is intermittent now, without understanding how the switches work, I'm afraid it will start working and I'll never understand the original failure.

At this point I know it is something to do with flap retraction. Extension works fine. Cycling the breaker will get the flaps up some of the time. That really sounds more like a sticking relay, not a switch issue.

Dealing with 40 year old relays and switches, it may make sense to do a clean sweep of the components and bring them into this century.

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has the problem recurred since cleaning the contacts perhaps that's all that was needed

I'm going to find out later today. Last weekend they began working a few days after I cleaned them with electronic cleaner and sprayed them with water proof silicone (if there is such a thing).

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