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Bachmann connector

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  • Member since
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  • From: Western, MA
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Posted by richg1998 on Monday, October 12, 2020 6:57 PM

About ten years ago with my Bachmann steamers, I carefully squirted hot glue to the back of the four pin and two pin connectors. When disconnecting, I use a flat jewelers crewdriver to gently pry a conector out while the loco and tender are in a foam cradle. I handle both gently when putting and removing on the rails.

Hand tremors have prevented that some time ago.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by RR_Mel on Saturday, October 10, 2020 6:55 PM

I use Amazing Goop to make strain relief for my tiny connectors.  It also works nicely on meter probes to prevent the test leads from coming off inside the handle at the test probe.







Mel



 
My Model Railroad   
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I'm beginning to realize that aging is not for wimps.

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Posted by Overmod on Saturday, October 10, 2020 6:15 PM

rrinker
 On bigger locos it would be nice if the decoder were in the loco, with maybe just a speaker in the tender - but you'd still need a 4 wire connection, 2 for the speaker and 2 for the backup light. But it's just too easy to put it all in the relatively vast space of the tender.

Why couldn't you use PoDL (as in 802.3bu-2016) and modulate the sound output as data with the superposed power for LED lighting?  On a stoker-equipped engine you could run this and the feeder pickup from the tender together through a scale 'auger' sleeve and have no visible wires at all...Wink

You could even carry the single twisted-pair down the consist and multiplex sound to it... while powering or trickle-charging car lighting.  This might also apply to decoder(s) set up in cars for running effects...

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Posted by Overmod on Saturday, October 10, 2020 5:57 PM

rrinker
And to take them apart - never pull on just one wire, they can't take that kind of force. Instead grasp all 9 or whatever, and gently wiggle.

General 'accepted wisdom' is not to pull on the wires to remove any connector unless there is a strain relief.  In the JST design there is not.

A trick in the RC community, where ZH connectors are often used for repeat charging, is to use a hot glue gun to lay a small bead across the back of the connector and wires, and then 'tool' it while still hot by squeezing with pliers that have crosshatch pattern.  That gives you something to grab that won't strip out of tiny crimped pins...


It does add to vertical clearance issues, though; yet another reason why vertical pin plugs facing straight down are stupid. I would be tempted to see whether bending the wires 90 degrees to the 'rear' and applying more hot glue to hold that alignment might be useful in such a case.

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Posted by RR_Mel on Saturday, October 10, 2020 2:47 PM

I eroded when I measured the Bachmann connector it isn’t a GH it’s a ZH.  My MRC decoders use ZH connectors and I pulled the 2pin on the Bachmann and the ZH is a perfect fit.  The ZH is a 1.5MM connector.
 

I don't know if it was my eye, my 20 year old digital caliper or just shaky Mel being 83 years old.

I also found some 4pin ZH connectors in my connector bin box and they fit the Bachmann perfect.

The 9pin connectors are ZH connectors also, sorry for the confusion.  I should have checked my connector bin instead of attempting to measure them.

Mel


 
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I'm beginning to realize that aging is not for wimps.

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Posted by drgwcs on Saturday, October 10, 2020 1:45 PM

RR_Mel

The connectors on my GS4 measure 1.25mm, I have some JST series GH and they are the same spacing as the Bachmann.

 

EDIT:

I keep the GH 9pin in stock for my decoders, I order them with wires and they come with the female board mount connector.  Sure beats messing around with the itty bitty contacts.

Mel


 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

 

So I assume the GH worked then plugging them in?? Thanks for the info.

 

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Posted by rrinker on Saturday, October 10, 2020 1:04 PM

 The only shortcoming I have seen so far in a factory loco was that one of the pins was not properly oriented in the plastic header, causing the pin to push back out when the connector was plugged in, rather than the pin making contact, That was a simple fix, just put the pin back in the shell facing the right way so the tab designed for the purpose could push out the small slot in the header. 

 The loco to tender connections loosen up with use, but initially they are pretty tight. To seat them all the way, I tend to use something that can press across a wide area of the shell, like tweezers, instead of a screwdriver, which if it slips off can just chear all the wires right off. And to take them apart - never pull on just one wire, they can't take that kind of force. Instead grasp all 9 or whatever, and gently wiggle.

 On bigger locos it would be nice if the decoder were int he loco, with maybe just a speaker in the tender - but you'd still need a 4 wire connection, 2 for the speaker and 2 for the backup light. But it's just too easy to put it all in the relatively vast space of the tender.

                      --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Overmod on Friday, October 9, 2020 10:47 PM

Note that there is a table of Japan Solderless Terminal sizes in the Wikipedia article on them.  Mel has discovered the Bachmann connectors are not GH size, but ZH, with 1.5mm pitch, a standard in the RC hobbies (see below).

For those plagued by crappy connectors, the JST company makes the tools (including a hand press) and special contacts for 'insulation Displacing' assembly.  This is akin to punch down fabrication of modular telephone or Ethernet cables.  Here is the official description and procedure:

http://www.jst-mfg.com/precaution/eP-IDC.pdf

It occurs to me that this would massively simplify the repair of various expletive-deleted manufacturer 'shortcomings' in termination quality while requiring only nominal shortening of factory wiring... and I suspect there is an analog for inline splice blocks to lengthen 'wires cut to length' so they stop being 'too short'.  Endless vigilance against the tag team of Murphy and Finagle is ever wise.

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Posted by RR_Mel on Friday, October 9, 2020 9:52 PM

The connectors on my GS4 measure 1.25mm, I have some JST series GH and they are the same spacing as the Bachmann.

 

EDIT:

I keep the GH 9pin in stock for my decoders, I order them with wires and they come with the female board mount connector.  Sure beats messing around with the itty bitty contacts.

Mel


 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

  • Member since
    June 2002
  • 365 posts
Bachmann connector
Posted by drgwcs on Friday, October 9, 2020 9:31 PM

I wonder does anyone know what specific JST connector that the Bachman 4 pin connectors use? I was looking on several on ebay and was thinking that it was the 1.25 mm pin spacing (1mm is too small) Any ideas. (My the time I order 2 from Bachmann w shipping it is 10 times what a bundle of 10 will cost)

Thanks

Jim

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