# B'mann 3-truck Shay Wiring Failures



## digger (Jan 2, 2008)

This may have been covered before, so if somebody can point me in the right direction....

The problem lies in the loco-to-third truck cables. The eight wires which pass between the two parts of the locomotive are bundled into two groups of four, which feed into an 8-pin female connector. The bundles are encased in a rather stiff tubing, which flexes very little as the lash-up negotiates curves, so the flexing of the wires is limited to about the last 1/16" before they run into the connector. The wires are fatiguing and breaking off at the connector. 

Hindsight tells me that I should have anticipated this and removed some of that stiff cladding to provide more strain relief, but I wasn't that smart. Now I have two wires which have failed, and six more that are about to go as well. I figure that if I could just get the broken stubs of wire out of that female connector, I could just redo the connections and move on. But I can't figure out how to get the &*)@!# things out!! Obviously, they're captured inside those tiny slots by something I can't see. 

I'm sure others have experienced the same problem. Help!!!


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## nkelsey (Jan 4, 2008)

Welcome to the world of cold solder joints on the Bachmann shay. The best thing is to replace the plugs and jacks, however, you will find that if you flex the wires going to the fuel tender pcb, they will separate from the pcb. I gutted my wiring, but I was also going Battery/Radio control.


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## Greg Elmassian (Jan 3, 2008)

Actually, it's the flexing here that is breaking the wires. The cold solder joints in other parts of the loco are an extra bonus. 

If you look at the connector closely, you may see where a small finger comes off the pin that locks it in the housing, possibly you can release it with a very small jewelers screwdriver. 

A close up picture of the end of the connector (the end the wires enter) might help. 

Regards, Greg


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## SteveC (Jan 2, 2008)

Ed

Kind of hard to address just how to extract the terminals from the connectors without a picture, but following are some types of terminals that show the small prong(s) some times there's just one on others there are multiple prongs (see red arrows) that is usually an integral part of the terminal itself that needs to be compressed to release it from the plug.














































Also many manufactures actually make and sell extraction tools for removing the terminals, however, unless you do a lot of this kind of work, the cost of the tools isn't worth it. Following is an example picture of one such extraction tool for round pin/socket terminals.


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## digger (Jan 2, 2008)

Thanks, Greg, for the hint on how to release the terminals. It worked. On one side of the female connector are narrow slots into which the retaining tangs seat themselves. Depressing the upper end of that tang releases the terminal and then it can be prodded out of the connector. The terminals are very tiny, ap. 7 mm. long by 1.5 mm dia. I think it's going to be darned near impossible to open the crimps to reuse them. I'd tried to get a picture, but these things are so small that I'd need a good macro lens, which I don't have, to show them in any detail. 

And thank you, Steve, for the diagrams. The clips Bachmann used are similar to the 2nd one on the top row, except that the retaining tang is on the opposite side. Now the trick will be to find replacement terminal clips and a tiny crimper to use them. Could you suggest a possible supplier? 

I know that it's possible to just bypass the whole Bachmann setup with other types of connectors, but that, too, would be a PITA which I'd rather avoid.


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## Greg Elmassian (Jan 3, 2008)

If they are not soldered, I have been able to open the crimps sometimes with using an x-acto blade to spread it open just a bit, then a small jewelers screwdriver in the "slot" twisted a bit to open it a bit further. It takes some coaxing, but it can be done sometimes. 

Regards, Greg


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## Del Tapparo (Jan 4, 2008)

Digger - Come and see me. I may have some that will work for you.


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## digger (Jan 2, 2008)

Thanks, Del, for the offer, even though it didn't produce what was needed. But with your consultation and Greg and Steve's posts, at least I found out how to releases the terminals from the 8-pin connector. I wasn't able to open up the smaller crimp on the terminals, but I got the larger ones open to release the insulation and stub of wire. The first thing I did, after mapping each wire's position in the connector, was strip back the cable cladding to the loco's end beam, leaving all eight wires free to flex independently. The cladding is still intact inside the fuel bunker where it is fixed in place with cable ties to prevent flexing at the "cold solder joints" on the circuit board. My plan now is to strip and tin the end of each wire, and solder it to a terminal, then reinsert it into the appropiate slot in the connector. This is going to be a challenge for my aging eyeballs, since these terminals are really tiny! Hopefully this will get the beast back into operation and the wires will hold up longer than the original connections did.


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## paintjockey (Jan 3, 2008)

If you have a Radio Shack near by they may carry the connector, usually in a 10 pack for a few dollars. (mine has them) 
Or http://www.allelectronics.com usually has them as well. I have repaired a few of them, mine and a few friends. It isn't that hard but you do need to trim back the hard sleeve a bit especially if you run the shay on tighter curves. I have also completely removed one for a person and added a different connector (actually two) altogether. But he always wants to connect and disconnect the tender for storage and carrying purposes and the B-mann supplied connector isn't condusive to that kind of use. 

Terry


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## Curmudgeon (Jan 11, 2008)

I have used the better plugs in conversions for years. 
I put an 8-pin replacement directly into the circuit board, as the ones provided suck. 
I also replace all 8 wires with super-flex, as if you ever go battery power, feeding power from the batteries in the water bunker to the control system in the fuel bunker you will get smoke. 
Three strand PRC wire also sucks. 

That is not the biggest problem, however. 
Where those wires connect to the factory circuit board in the fuel bunker....there is no solder strain relief in the wires, and no physical strain relief to the chassis. 

Not sure where it is anymore, but there was a tutorial on-line to show how to fix that.


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## digger (Jan 2, 2008)

I followed the tutorial shortly after I bought my Shay, so the fuel bunker circuit board connections will (hopefully) remain intact. THanks for posting that. It saved me at least one of the potential headaches!


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