# Another DCC question



## K Harm (1 mo ago)

I have had a basic kitchen table HO layout every Christmas for years and have acquired a few analog/DC locomotives. I got tired of running 2 concentric tracks with separate power, etc, and thought it might be good to explore DCC with a trial loco and a second DC locomotive. Last year I picked up a Bachmann EZ command that I thought would fit the bill, with the expectation that I would be able to upgrade at least one of my DC locomotives to DCC - looked pretty straightforward - until I saw the plethora of DCC converters and also the difficulty of fitting one in my steam locomotives (all of them are). So plan B was. To find a used one, which I did, at a swap meet, a Bachman spectrum 4-6-0 82302. The seller confirmed it had an operational DCC card and the price was good. Weeeeeeeeellll, I have now been educated that there are DC/DCC setups with a digital sound card only and a DC motor. So I am no better off than I was. So question: is there a way to upgrade the partial-DCC equipment I have in the locomotive? Any experienced advice is appreciated.


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## Dennis461 (Jan 5, 2018)

I think you bought a DCC Ready loco.
Ready
Not a DCC loco.
If it looks like mine, you need a decoder to plug into the tender.
There is a small circuit board the plugs in to make the loco run on DC only.
Remove the small circuit board, plug in the decoder, then run on DCC layout.


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## K Harm (1 mo ago)

First of all, thank you for your reply and assistance. I apologize for my continued questions, but believe it or not there are no local clubs that I can access for help. Here is my naked circuit board and it appears to be similar to yours. Is there a database or list that I can reference to find a suitable decoder compatible with this setup? Also, although I have some experience in things electrical, it is limited to assembling old Dynaco amplifiers and wiring light switches and fans! So, would this decoder be a remove-and-replace? Or would I access soldering points on the current circuit board? I certainly don't see any receptacles for plugging in a unit. Again, I am sorry for all the questions but appreciate any advice. Ken


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## DonR (Oct 18, 2012)

Plug in decoders have either 8 or 9 pin 
connectors. You can check your
tender for the right # of pins. Then
select any Digitrax or NEC decoder
with the same number of pins. The
new decoder will come with address
# 3. You'll want to change this to
the loco's 4 digit road number.
Choose one with sound if that
is what you expect. 

Don


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## Dennis461 (Jan 5, 2018)

You need a SMALL non sound decoder
I think a Digitrax DN136PS will fit, and has the 8-pin plug.
Pay attention to color code.when you plug it in


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## MichaelE (Mar 7, 2018)

There are a lot more decoder configurations out there than only 8 or 9 pin. There are also 6, 12, 16, 18, and 21 pin decoders. All have NEM designations assigned to them.


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## JeffHurl (Apr 22, 2021)

Just out of curiosity (I'm N scale, so having that much room inside a loco is foreign to me), is the smaller PCB the one that needs removed and replaced with a DCC decoder? Does it just lift up and away? Are the "pins" more like spade connectors that you can sort of see between the 2 PCBs??


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## K Harm (1 mo ago)

So if I am getting all of this, the small PCB with 8 connectors hovering over the main board which also is labeled “8” is the plug-in that I just remove (hopefully no special tools) and plug in the 8 pin DCC (the Digitrax is certainly affordable enough for experimentation) and I am off to the races on address #3. Thanks, all, I will post results!


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## Dennis461 (Jan 5, 2018)

It will be tight, be careful pulling/prying it.


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## J.Albert1949 (Feb 3, 2018)

*OP:*

I've only done diesel DC-to-dcc conversions, not steam.

But looking at your pic, and at the one Dennis posted in reply 9, looks like a DC light board in the tender with an 8-pin "dummy plug" in place on it. That's what is circled "in red" in reply 9 above.

You need to GENTLY lift the dummy plug off (I've found that using a LARGE-blade screwdriver helps), and replace it with a dcc decoder.

You might use a decoder that has a short wire "harness" like this one from Digitrax:








Or, I'm wondering if one of the "postage-stamp" size decoders would work, perhaps something like this (TCS DP2X-UK):








TCS has a page showing different decoder installations.
They DON'T have one for a Spectrum 4-6-0.
However...
The DO have one for a Spectrum 2-8-0:





| Train Control Systems







drupal.tcsdcc.com




So you can see what's involved.

These are *NON-sound* dcc conversions, as in "motor & light control" only.
If you want sound, well, that's an entirely different ball game.
I don't care for it myself, it will be up to others to offer help.

*EDIT:*
_Hmmmm...._

As I look at the pic above of the light board, I'm wondering if using a decoder with a "short" harness might cause problems. The reason is because of how the 8-pin port is located on the light board.

If you plug the decoder in, in order to fit, it may involve "twisting the wires" to do so, and the short harness may not give enough flexibility.

In that case, you could use a slightly longer harness, like this one:








Now the issue is: Is there enough room in the small tender to tuck in all the wires?
Depends on your needs.

Decoder installations must often be done on a "case-by-case" basis (the opposite of "one size fits all").

I'm thinking that the TCS type decoder might be better, IF there is enough "side clearance" for the shell to go back on after you install it.
Based on the pic you posted above, it looks to me as if there IS enough.


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## K Harm (1 mo ago)

Thank you. I have not followed up on the discussion as I was waiting for the decoder to arrive; which it did last evening. The transplant was easily accomplished and the loco runs normally on DCC control. However, now I have another niggle that I am sure will be elementary to you all. The headlamp is now inoperable. I have included the page of instructions and a close-up of the PCB, but I remain unclear how to proceed. There is a red lead from the loco that seems to be soldered to LED2 and an oange wire adjacent that might be the other wire lead completing the circuit, but how is that related to the blue/white wires in the instructions?
Also, here is a free green lead from the decoder and no reference on how or whether to connect it to ??anything. 
Yet another leap in technology that requires re-learning....


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## K Harm (1 mo ago)

Subsequent to above, I decided to just button everything up and use the setup as is, and not worry about lighting for a time. . Unfortunately there is some error in information processing for the motor. It will run very slowly, or wise open - nothing in between. I have checked all of the connections and everything seems to be OK otherwise - if I replace the decoder with the original jumper board everything is back to normal. Suggestions? Thanks!


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## J.Albert1949 (Feb 3, 2018)

Looking at the pic you posted in #12 above, it looks to me that the wire "lead" from the 8 pin plug isn't plugged all the way into the decoder board connector (see arrow below).

Seems to me that the entire plug should fit much more "snugly" than I see in that pic. Look CLOSELY at the real thing (not at the pic), and you will see how far it needs to go. It should be snugly in on BOTH ends.

You may have to cut & peel away a little of the red plastic "insulation" to get the plug to go in all the way.


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## J.Albert1949 (Feb 3, 2018)

_"The headlamp is now inoperable. I have included the page of instructions and a close-up of the PCB, but I remain unclear how to proceed. There is a red lead from the loco that seems to be soldered to LED2 and an oange wire adjacent that might be the other wire lead completing the circuit, but how is that related to the blue/white wires in the instructions?"_

You shouldn't need to be soldering anything.

The headlight connection/control should be integral to the decoder (as installed) -- the connections are "right there" on the 8-pin connector.
*White* wire -- headlight
*Yellow* wire -- rear/backup light
*Blue* wire -- return for both lights









I believe the default setting for the headlight is F0 (zero) on your dcc controller.
If that's not working, I suggest you try F1, F2, F3.


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## K Harm (1 mo ago)

Again, many thanks for all who have offered guidance and solutions to my newbie inquiries. At best, with the decoder in place, the loco will operate and lights work, but there is still poor control of the motor. Advancing the throttle from low, with a crawling speed, in small increments and being patient, offers first no change, and then a sudden marked jump to moderate/high speed and then almost comical frantic full speed. Nothing in between. Even at the lower speeds, the loco will intermittently advance to full speed, spinning its wheels for a few seconds before returning to prior speed. Trying to reverse the loco yields only intermittent lunges backwards. I communicated with the folks at DigiTraxx, and their opinion is that my controller has some issue. Trying to get some response from Bachmann has been met with silence. So I am back to DC for the time being, and I guess I will re-address this some other time. Merry Christmas to all of you!


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## CTValleyRR (Jul 26, 2014)

Now that you have a decoder installed, it's time to update the settings. I scanned back over the previous entries and I do not see what kind of a DCC system you have. First, put your loco on a programming track (if you have one), or remove all other locomotives from your layout. Use your DCC handset to select either programming track or program on the main (actual terminology may be different, depending on the brand of DCC system you have). After programming the locomotive number, it should give you the option to program Min and Max voltages (sometimes called STARTING volts). This is largely a trial and error process, but you need to give the motor enough voltage at "start" that it just creeps along, and set the max voltage to a number that limits the speed to what you want it to be. Again, the specifics of doing this will vary, depending on the brand of DCC system you have. Consult your system manual for directions (or the back of the handset on an MRC system).

Note that if you have a "limited feature" system, like Bachmann's EZ Command or MRC Prodigy Explorer, you will not be able to change those settings.


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