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Wiring for HO 2-8-8-4

Started by 44ruffmapa, September 25, 2014, 05:04:23 PM

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I was given an HO 2-8-8-4 with no tender, so ordered a tender and decoder from Bachmann.  Since almost all the wires from the engine are black, can someone tell me what sequence the 4 pin and 2 pin connections under the engine are and how they connect to the decoder?  Thanks.


I just looked at the diagram in the Parts Page for that tender and it is made to plug right into the loco.
The two pin connector is for track pickup. The four pin for motor power and loco headlight.
Using an ohmmeter, you can find out which two pins are for left and right drivers.
Two leads on the four pin connector will measure maybe in the vicinity of 100 ohms.
Two pins will be for the headlight which I think will be a LED. If it is an LED, you will see max resistance.
Some use a 9 volt battery and 1k resistor to see if the headlight comes on.

I am assuming you bought all the required parts.
Hopefully the PC board comes with instructions. The picture  of the PC board did not show any labels.
Others will comment.
Jonathan here is really savvy when it comes to this loco.



Right, but I need to know which of the 4 pins under the engine go to which connection on the decoder and which of the two pins goes to the right pickup.


Quote from: 44ruffmapa on September 25, 2014, 06:09:11 PM
Right, but I need to know which of the 4 pins under the engine go to which connection on the decoder and which of the two pins goes to the right pickup.

On the two pin connector, one pin for the right side. One pin for the left side. Check with your ohm meter.
There have been diagrams posted here in the past but not about this loco.

On the four pin, you should see somewhere in the vicinity of 100 ohms which will be the motor.
I have done this in the past so I know it works.

The other two pins will show max resistance. LED's show max resistance with an ohm meter. Some use a 9 volt battery with a 1 k resistor to check an LED.

Have not heard of anyone ever doing this with this loco so it might be a first. Would be good if you take pictures and document this for the model railroad community. I am sure, you realize this is not plug and play.
Tender wiring in Bachmann locos has been an issue here for some time.
Sorry to have to say it but Bachmann does expect users to have electrical knowledge when they work at what is called the component level.



If you have not done it, go look at all the diagram pages for this loco. Nothing about wiring though.
Bachmann is noted for changing canoes in the middle of the steam.
Wiring colors is a noted issue.

You can also search the General and HO forum for the EM1. There has been other discussions about different aspects of this loco.



Here's one way, not necessarily the easiest or right:

If you remove the locomotive shell, the small boards that lead to the receptacles, are marked for Motor-Right (+), Left (-) and so on.  In fact, I believe I took a couple of photos and indicated which wires go to what.,18857.0.html