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D-Sub connector loose Screw

rockwoodrv9

rockwoodrv9

Well Known Member
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I pulled my G3X out this afternoon to check a wire and noticed this. The screw on connector on the D-Sub connector on my backup battery was loose. I was shocked - never seen that before.

I checked all the other connectors and I found 2 other ones that were loose too. Of those three, all had one that was tight and one loose.

I am only a couple months till my annual so I will check my servo connectors in my wings tomorrow before I fly. I am not sure if I checked them last annual. I will for sure now.
 

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I've seen the cheap plastic ones loosen up many times. Between the plastic becoming brittle and cracking, and the lack of any kind of lock washer, there isn't a lot to help keep these tight. (can't tell if the one in this picture is all-metal or metal-coated plastic)

Your Garmin connectors have provisions to tighten the thumbscrews with a hex wrench, and there are holes for safety wire if you really want extra security.
 
rockwoodrv9 said:
I pulled my G3X out this afternoon to check a wire and noticed this. The screw on connector on the D-Sub connector on my backup battery was loose. I was shocked - never seen that before.

I checked all the other connectors and I found 2 other ones that were loose too. Of those three, all had one that was tight and one loose.

I am only a couple months till my annual so I will check my servo connectors in my wings tomorrow before I fly. I am not sure if I checked them last annual. I will for sure now.
Click to expand...

I've never liked these as a connector securing mechanism. I think they're a ****-poor solution, but they seem to be pretty common, and yes, I've found a few loose over the years. I suppose you could use a little blue Loctite if you wanted.

I don't know why a better connector wasn't chosen by so many manufacturers/vendors for what would generally be considered a moderate vibration environment.

Tighten 'em up as best you can, and check regularly. That's about all you can do in most cases, I guess.
 
D-subs

I secure pairs of d-subs with wrap of waxed lashing string. All my connections are D-sub of various counts.
Screws on devices are another issue. A tiny bit of blue loctite would help. If there's a way to lash them, I would. Even if the screw came loose the lashing would keep them seated.
 
It may help to have the wire loom exiting straight downward, and cable tied to something. Going sideways is pulling the plug out slightly.
 
Careful with over-tightening or using Loctite on DSub screws. Sometimes when DSub mounting screws are over tightened or thread lock is used the breakout torque when removing later for maintenance can cause the chassis nut on the mating component to back out of it's bulkhead connector and stay on the screw. Basically the DSub screw becomes an extraction tool for the chassis nut. That leads to having to open up the component to repair the socket with associated risks of physical or electrostatic damage. I would rather the nuts stay on the avionic or component and find a more mechanical way to failsafe the connection screws similar to wirejock's wax cord idea above.
 
Thumb screws

Here's another idea. We are expirementors.
Thumb screws are available in all lengths.
Disassemble the conenctor and install slightly longer screws with a lock washer. The trick is finding all the parts.
 
I haven't flown so I have zero experience with dsub housing screws. But in my panel and the associated network hubs, all my connectors are either horizontal or vertical with the connectors pointing down (the thumb of the screws pointing up). So if the screws work themselves lose, I hope gravity still hold the housings in place.
 
Make sure you wiggle the connectors as you tighten the jackscrews. The screws hold the connectors together, but don't count on them to draw them together.

And yeah, if you get them too tight (no Loctite), when you take them out you'll end up with the equipment-side nuts coming out too. Then you'll have something to think about!

Equipment connectors pointing "up" is avoided in the industry, if not downright prohibited, as they tend to collect FOD and water/liquids. In fact, we try to orient all of our circuit boards vertically for the same reason. Le$$on$ learned and all that....:rolleyes:
 
wirejock said:
Here's another idea. We are expirementors.
Thumb screws are available in all lengths.
Disassemble the conenctor and install slightly longer screws with a lock washer. The trick is finding all the parts.
Click to expand...

I don't understand this proposal. Where would you put a lock washer on the things that it would prevent the long-shanked knurled knob screw from turning?
 
Thumb screw

RV7A Flyer said:
I don't understand this proposal. Where would you put a lock washer on the things that it would prevent the long-shanked knurled knob screw from turning?
Click to expand...

I haven't actually done it, but I do use the lock washer on the nut-screw side. Slip it on the thumb screw before it goes into the hole and before closing the clamshells
 
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Vibra-Tite VC-3

How about Vibra-Tite VC-3?

Or VC-4, -5, or -6 if choice of base solvent is an issue but Vibra-Tite says to let that evaporate before assembly anyway.
.
 
Use a piece of rubber tubing that fits snug on the jackscrews and cut it long enough to form a U between them....
 
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