Safely disconnecting PC jumpers

Apr 20, 2008 11 Replies

I'm trying to repair a balky piece of ham gear... trying to check some suspect solder connections on the back side of a board... can't figure out how to get the board loose so I can access the back side!



Problem is those little interboard connectors. Rectangular white plastic connectors on the board, wires crimped to pins that insert in brown plastic shell that plugs into the white shell on the board.


- Grab the wire & pull? I've made that mistake in the past with other gear... managed to pull the wire out of the pin, leaving the shell firmly in place with the rest of the wires.


- Grab the shell with a long-nosed pliers & pull? Doesn't work any better. There isn't enough exposed plastic shell to get a good hold; the pliers slip & threaten to grab the wire & yank it out of the pin. (as above) (luckily I haven't actually yanked a wire loose this way but that's only due to sheer luck.)


- Use a small flat-blade screwdriver to pry up on the two ends of the plastic shell? The shell seems to be so firmly seated that, rather than prying the shell out of the board end of the connector, I'm prying the entire connector off the board. (I'm stopping before using anywhere near that much force!)


- Tilt the board back with the wires still connected? Would love to do that but the wire in question is way too short.



The problem seems to be that the plastic shell on the cable mates so snugly with the plastic shell on the board that the amount of force necessary to separate them exceeds the amount necessary to pull the wires loose or to pull the connector off the board.



What's the trick to getting these disconnected without destroying anything?



Please don't tell me some manufacturers are gluing these together after assembly?! (though at this point I'd believe it, despite not seeing any glue)



Uh... pull them off with your fingers.

The advantage of "doing it by hand" is that you can gently flex, angle, or twist the connector as you judge fit.

I'd be looking for a latch. Once released, you should be able to pull the connector off the header fairly readily. How about a couple of pictures of the device in question?

How about taking a picture and uploading to tinypic.com then posting the link so I can have a look. I'm going on my 3rd decade of being a ham and I've done a lot of repair. I think I know what you're trying to do but would like to see before I advise.

I think the OP should keep in mind that everything that looks like a plug & socket, isn't. I've seen plastic headers which looked like they should unplug, but were just one piece. Usually when that was the case, the OTHER end of the cable in question had a plug/socket combo...very similar looking.

IOW, one one end was designed to unplug.

jak

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A bit fuzzy but I think it's clear enough to show what kind of connector I'm talking about.

I've seen these in Panasonic professional video gear as well but luckily have never had to disassemble the video stuff.

Yes, I've seen that. But usually if you look closely you can see there's only a single plastic piece.

There are definitely two pieces here. And I've been able to disconnect other identical plugs on the same board. (indeed, if you look at the image on the URL I posted, I've been able to unplug the larger - 4 pin - plug. It's the 2-pin plug in the photo I'm having trouble with - and fear I'll have trouble with two more larger plugs that aren't in the photo.)

There are anti-vibration connectors in which pulling the wires makes the connector bite into the pin; they *must* be removed by pulling the plastic body, which causes the connectors to unlatch.

If you're sure that's *not* what you have, try grasping all the wires at once and "rocking" the connector back and forth along the long axis while pulling -- but don't rock so far that you bend the pins.

Isaac

Doug Smith W9WI wrote in news: snipped-for-privacy@invalid.nospam:

use a pair of pliers that is wide enough to get the width of the connector. such as

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Wiggle gently while pulling on the brown part of the connector.

bz 73 de N5BZ k please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. bz+ser@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap

Well, I got it. Had to be slightly destructive but not seriously so.

The problem seems to be (as one might guess) with a latch, not visible in the photos. Square hole in the board-side shell, "bump" on the plug shell, doesn't want to push the top of the hole out of the way. 4-pin connectors come apart OK because there's a longer unsupported span. 2-pin connectors are a problem.

I tried using a jeweler's screwdriver to pry one apart from the latch side. Inadvertently broke the top of the latch - and a reasonable amount of force proved adequate to separate the connector. Repeated with the other one, and we're in business.

Now, to hope that touching up the back of the board brings this thing back around..... (some of the connections *do* look a bit suspicious)

Guess I was hoping there was some magic trick to this...

Here is a tip for taking close up pictures. Look for a setting called macro on your camera. Many times they use a picture of a flower on your camera to represent this function. It allows your camera to take clear pictures at very close range. Your image would be more informative with a clear picture.

Mike

These connectors _look_ as if they should come loose by pulling on the white side to release them. But the image is badly blurred it's hard to tell. I'm surprised the camera fired, given how badly out-of-focus the shot is.

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