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DCC Decoder wiring curiosity

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  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Wednesday, September 18, 2019 2:52 PM

wjstix

A lot of engines made in the last 10 years or so have both the 8- and 9-pin receptacles, although in the last couple of years a lot of engines have a 21-pin receptacle instead of one of the others.

Besides what I would think is the hassle of having to open up an engine to take out a decoder and open up another one to add the decoder so I can run it on DCC, there's the concern that everytime you do that you're risking breaking one of pins on the decoder, rendering it inoperative. I'd suggest looking at just little by little adding decoders to all your engines. If you shop in bulk, like say 5 at a time, there are good non-sound decoders you can pick up for around $15 each (maybe less).

BTW, if you've removed a decoder from an engine, you do have to put in a dummy plug to run it on DC. However, the majority of decoders are 'dual-mode' so will work fine on DC without removing it.

 

Actually I’ve been swapping decoders and dummy plugs for close to ten years and so far I’ve never had a problem with breaking the connector pins.  I use the round pin header strip connectors for all of my locomotives as well as for anything needing a small connector on my layout for at least 8 years and never a problem with the pins.
 
I have only used the JST decoder connectors for about three years and no problem there either.
 
I don’t do the swapping thing very often, maybe twice a month or so.  Usually when a visitor wants to see a specific locomotive run with sound.  I pretty much run in DC mode most of the time.  I do have a DCC passenger train parked on a hidden siding that I run quite often.
 
I’m not in love with DCC, I like the sound (my only reason for DCC in the first place) and lately the F functions for controlling lighting and remote uncoupling but I still run more in DC mode than DCC mode.
 
I only have a few decoders and don’t plan on buying more.  My layout is small and I can’t run multiple trains at the same time and swapping the decoders around occasionally doesn’t bother me.
 
The locomotives I run the most in both modes are Cab Forwards and passenger E7s.  I have two spare oil tenders with sound decoders that simply plug in to any of my 13 SP Cab Forwards.
 
 
 
I have two pairs of E7s with EMD 567 sound decoders, I have two pairs with motor decoders that get swapped around to a couple dozen road diesels.
 
 
This is a SP Daylight E7B with a MRC1730 EMD 567 sound decoder.  The decoder has a 9 pin JST connector and no NMRA 8 pin in the E7B connector wiring on this one.  The pig tail on the end of the frame is the rail power to the E7A for all wheel power pickup.
 
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Wednesday, September 18, 2019 12:08 PM

Just remember, a dual mode decoder will not start running until the voltage is about seven volts DC. Nature of the beast. It does not need more power, just more voltage. The decoder wakes up at five volts DC.

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.

  • Member since
    February 2002
  • From: Mpls/St.Paul
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Posted by wjstix on Wednesday, September 18, 2019 11:52 AM

A lot of engines made in the last 10 years or so have both the 8- and 9-pin receptacles, although in the last couple of years a lot of engines have a 21-pin receptacle instead of one of the others.

Besides what I would think is the hassle of having to open up an engine to take out a decoder and open up another one to add the decoder so I can run it on DCC, there's the concern that everytime you do that you're risking breaking one of pins on the decoder, rendering it inoperative. I'd suggest looking at just little by little adding decoders to all your engines. If you shop in bulk, like say 5 at a time, there are good non-sound decoders you can pick up for around $15 each (maybe less).

BTW, if you've removed a decoder from an engine, you do have to put in a dummy plug to run it on DC. However, the majority of decoders are 'dual-mode' so will work fine on DC without removing it.

Stix
  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Wednesday, September 18, 2019 10:34 AM

Bachmann DCC ready locos are different. There is a HO Bachmann forum with users and company reps and loco diagrams and parts list.

I have some Bachmann diesels and steamers. They have only eight pin sockets. Well so far have never seen JST sockets on them.

Edit.

There are a couple Bachmann with 21 pin but I do not believe they are DCC ready.

I have a 44 ton DCC ready that I had to remove two clips and solder in a seven pin decoder. Same with a 0-6-0 DCC ready.

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.

  • Member since
    February 2008
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Posted by kasskaboose on Wednesday, September 18, 2019 10:04 AM

Way cool about swapping out different decoders.  I was fearful of how to add the wires and found that the process is literally plug n' play.  The decoders you show are exactly what I have and they are on modern (read DCC ready) Athearn locos.  I have one Bachman DCC ready loco and it should work that way.  If not, coming here! Super Angry

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
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Posted by RR_Mel on Tuesday, September 17, 2019 8:03 PM

Early on I removed the 8 pin wiring and installed the JST connector in two E7 AB pairs.  Later when I wanted to run them on DC I made a couple of JST DC dummy plugs.
 
 
I used an 8 pin socket for the connections to the E7 Model Power metal shell, my E7-A requires 6 wires between the shell and frame.  2 wires for the speaker and 4 for MARS and headlight.
 
I would like to keep my wiring as close to standard DCC as I can.
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Tuesday, September 17, 2019 2:58 PM

I have heard of those in some Athearn diesels. At one time
Athearn only had the JST connector I believe.

Some years ago, maybe ten, I bought the Roundhouse Steamers DCC Ready sold by Athearn and they came with the JST DC adapter which I removed.

I hard wired a SoundTraxx Micro.

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.

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
DCC Decoder wiring curiosity
Posted by RR_Mel on Tuesday, September 17, 2019 2:46 PM

First I model the mid to early 1950s in HO scale since 1951.  My current layout was started in 1988 and far from finished, the Mel Construction crew are slow workers.
 
I’m just curious about the DCC wiring in newer locomotives.  I haven’t bought a new locomotive in about 10 years and I’m wondering what changes have occurred and or the current way of wiring things.
 
I’m not into buying new locomotives for a couple of reasons, 1) retirement income, 2) I don’t plan on adding any new locomotives to my inventory, I have too many now.  I just like to keep up on what’s going on.
 
I wired almost all of my 70+ older locomotives for a DCC decoder using the NMRA 8 pin connector many years ago.  After buying a couple of newer decoders having the 9 pin JST connector I rewired several diesels for the 9 pin connector but left the 8 pin NMRA socket intact to accept a 8 pin DC dummy plug when the decoder has been removed so that they will operate on DC.  I run my layout in both DC or DCC modes.  About 30% DCC, when I’m working on or around my layout I let a DC train run my mainline loop at about a scale 35 MPH.
 
Being on a retirement income I only have 13 decoders and don’t plan on increasing that very much.  I swap the decoders around to the locomotives I want to run in DCC mode.
 
I found this picture of an Athearn DCC interface board with a Google search.
 
 
Is this pretty much standard, both the 8 pin NMRA and the JST 9 pin sockets?
 
 
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

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