Wire pulled/broke out of 4 pin DCC plug


malibu43

malibu43

Active Member
Hi,

I'm not very familiar or experienced with DCC/wiring, etc...

I got a DCC equipped SP 4-8-4 from Bachmann a few years back, and I just run it once a year when we set up a track around our Christmas tree. I just use the locomotive DC since I just have the one loop and my controller is an old DC controller.

I was trying to separate the tender from the locomotive tonight so I could put the loco away in it's box. Unfortunately I was in a hurry and a little distracted, and ended up pulling one of the wires out of the 4 pin connector when I was trying to unplug the tender (stupid me).

2013-12-05214239_zps01ab73a9.jpg


I have a few questions:

1. Edit - Ignore this question. I tried the loco and it no longer works. There is also a connector with 2 wires/pins. Is the one I broke just related to DCC?

2. If the answer to #1 is yes, can I still use the locomotive on my DC loop without repairing the broken connector/wire? Edit - Doesn't matter. Answer to #1 is NO.

3. What's the best way to fix the connector/wire? The wire is actually broken just inside the plastic connector. I tried to use a very small screwdriver to depress what I thought was a tab and maybe remove the metal connector that was soldered (or crimped) on the end of the individual wire, hoping I could strip the wire and re-attach it. However, I couldn't get the metal connector out of the larger plastic piece. Should I try to repair the connector, or do I need to get a new decoder?

4. Can anyone tell me how to get the shell off the tender? (in case I need to put a new decoder in) I tried looking at the exploded view on the backmann website, but it wasn't very helpful.

5. Edit - additional question. If I do need to replace the entire decoder, what's the cheapest way to do it, given that I plan on just running DC?

Thanks!

Gregg
 
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I just did this exact same thing recently. The problem is those connectors are too tight, and sometimes they just won't come out. What a pain in the ass.

I fixed mine though. First on the connector, get a hobby knife inside there, and twist and turn until the metal piece opens up a bit. Then strip the wire, and twist it very tight with your fingers. Then insert it into the metal piece in the connector. Then very carefully, don't move that wire, and put little bit of super glue in there to secure the wire.
 
Following Motley's guide, you should be able to pre solder the wire before fitting it into the plug. Touch the soldering iron to the exposed wire as close to the plug as you can and the heat should travel to the solder on the end of the wire that is inside the plug.
 
Thanks guys. I'll look into that.

My case may be a little different, though. It looks like there is still a piece of wire inside the connector. I'm not sure how to get that out...

Also, is that wire soldered to the decoder on the other end? Buying a $20 decoder might be better than me spending 3 hours trying to fix it. If that wire runs back and is soldered to something more expensive or difficult to replace, then it might be worth the effort to try and fix it.

Thanks.
 
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Answered my own question again. I got the shell off the tender, which was good. But I now see that the broken wire is probably soldered to the board in tender, which means I'd have to replace the entire board (not just the decoder).

Looks like it's worth it to try and repair the broken wire. Does anyone know what the name/type is for the plastic connector? I could just cut the remaining 3 wires, strip them, and the put all 4 wires in a new connector...
 
That is a reasonable option, replacing the entire plug. Just be sure to lable the wires before ya cut them off the connector. If you can find the same type connector, you won't have to replace the good one.
 
OK. I got the metal clip/connector out of the plastic connector by lifting the the plastic tab on the connector with a very small screwdriver and then pushing it out.. I then used a razor blade to pry open the back end of the metal connector and then scraped/cut out as much of the old wire as I could. Now all I need to do it strip a little bit off the end of the wire, place it in the metal connector, and squeeze the end of it back together to hold the wire in place. I can also add a drop of super glue for good measure. Then I'll slide the metal connector back into the plastic connector.

None of this would have been possible if it hadn't been for the fact that I have access to 40x magnification microscopes at work. Maybe I can take some magnified pictures too, just for fun.
 
All done. Here's some shots:

Here's the plastic connector with the wire/metal connector removed:
plasticconnector_zpse6cd495b.jpg


Here's the metal connector after I removed it and pried it open to get most of the old wire out. You can see that I was only able to open up the back by prying with a razor blade. The tabs toward the front were too tightly clamped together.

metalconnector_zpsf8a4c388.jpg


metalconnector2_zpsa59322f3.jpg


It took a little bit of experimentation to figure out the best way to re-attach the wire to the metal connector. I initially just fed the stripped wire through the tabs at the back, but it was still loose once I pinched the tabs shut (because those tabs were designed to go around the un-stripped wire). Some trials using CA glue and solder to then hold it in place didn't work very well.

What I settled on was stripping a longer length, feeding it through the tabs, pinching them as tightly as I could (which created a "snug" fit) and then wrapping the excess wire back around. I then put a small drop of CA on top to help keep the wire wrapped over the connector.

re-attached1_zpscc86192c.jpg


Here is the connector reassembled.

re-attached2_zps60dded4a.jpg


I will try it out when I get home. My only concern is that the CA wicked in around the individual wires and connector too well, insulating the joint. I'm hoping there's enough contact where the tabs are pinched to conduct. If not, I may have to take the entire thing apart again, remove the CA, and try something more conductive. Solder or something else...
 
Ahh very nice, the repairs look good. Why didn't soldering this work? it wouldn't stick to the connector?

I sure wish I had access to a maginfying scope. I really need to get something to help with things like this.
 
Motley said:
Ahh very nice, the repairs look good. Why didn't soldering this work? it wouldn't stick to the connector?

I sure wish I had access to a maginfying scope. I really need to get something to help with things like this.
Click to expand...

The soldering iron (that we have at work) had a very fine point, but had a bunch of crud on it. I had to use a big fat part of the soldering iron to get anything hot enough, and then it was too big to fit in that tiny little space. Also, it seemed like any time I started getting things hot enough to solder, the insulation on the wire would start shrinking back. In actuality, I didn't re-strip the wire to expose more of the internal wire like I said I did; the insulation pulled back due to heat from soldering.

I'm sure someone better at soldering or with better equipment could get the solder to work. The space was just too small for my skill level and equipment.

I did borrow a Fluke multi-meter from one of my coworkers, and it looks like the resistance is the same across my new connection as the other connections. Will verify that it works when I get home.

...and then I'm never pulling that plug out ever again!
 
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Good job. Well thought out. When the soldering iron gets crud built up on the point, just use a file to grind it off. I use a file to keep the point on my soldering iron at a point for doing the signal work that I'm progressing through. The tip is designed to be replaced when it wears out.
 
D&J RailRoad said:
Good job. Well thought out. When the soldering iron gets crud built up on the point, just use a file to grind it off. I use a file to keep the point on my soldering iron at a point for doing the signal work that I'm progressing through. The tip is designed to be replaced when it wears out.
Click to expand...

In hindsight, I gave up on soldering before I settled on my final choice of wrapping the wire around the connector. I initially was trying to solder down inside the connector. I probably would have been able to get solder up on top of the wire where it wraps over, but by the time I got to that lunch was over and the soldering iron was being used. For now the glue is working. If it comes apart, I'll solder it next time.
 
Motley said:
I just did this exact same thing recently. The problem is those connectors are too tight, and sometimes they just won't come out. What a pain in the ass.

I fixed mine though. First on the connector, get a hobby knife inside there, and twist and turn until the metal piece opens up a bit. Then strip the wire, and twist it very tight with your fingers. Then insert it into the metal piece in the connector. Then very carefully, don't move that wire, and put little bit of super glue in there to secure the wire.
Click to expand...

Hey Motley - can you take a picture of the wiring on the PC board (or whatever it's called) in the tender?

Long story - when I was fixing the connector, I scratched the paint up on the tender. It wasn't horrible, but I really like this loco so I ordered another tender shell from Bachmann. $28 later, I was putting the new shell on and accidentally pulled one of the wires for the rear headlight off the board. While I was trying to resolder it, I pulled the other one off. I thought I got them both soldered back in the correct place, but when I finally got the loco back on a track, I have no rear headlight. Not a huge deal (I'm probably never going to really use it in reverse), but still a bit of a bummer. I just wanted to make sure I attempted to solder the wires back into the correct places.

Side note - I have a couple of blue box Athearn GP's and an IHC mogul that I've had for over 15 years. I got them when I was in Jr High/High School and to be honest it's not like I took amazing care of them. They all still run amazing and really have no/limited physical or cosmetic damage. They've been in and out of their boxes probably hundreds of times and have each probably been dropped or knocked over a few times. I've had this Bachmann GS4 for about 3 years, and the total amount of time it's been out of it's box can be measured in hours. I've been extremely careful with it since it's something I wanted ever since I was about 6 years old. And the freakin' thing is still falling apart left and right! It's a nice looking loco, but it's not a durable as what I'm used to!
 
Never mind the wiring pic. I took a wild guess, pulled the shell off the tender, unplugged the wires to the rear LED and plugged them back in with the opposite polarity. That did the trick! They came unplugged the first time and just plugged them back in, not knowing LEDs had specific + and - terminals.

I have to say, after getting those wires soldered back onto the PC board, I'm wishing I would have tried a little harder to solder the broken connector the first time. Oh well. At least I know I can solder it if the glue doesn't hold...
 
Malibu43,

Next time, save yourself some grief. Just unscrew the board, and turn it over. While B'man has several variations on their circuit boards they do have one thing in common, all the connection points for the wires are labelled on the back side. They will have things like LED1 and LED2, which indicated the front headlight, (LED1), and the rear light, (LED2). Motor leads on the ones I've removed have Motor+, or MTR+, and Motor-.

I've seen the pickups labeled PKUP+ but also PUP+. No matter what is printed, its easily figured out.
 
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