Orientation of wires in plugs

[Limey]

question for the Bachmann,
The plugs that connect the tenders to the loco have a small protrusion on them, relative to this protrusion what is the orientation of the wires.
Am I right in assuming that the 4 wire plug is power supply to the motor and to the headlight and that the two wire plug is for the light at the back of the tender. If so which wires of the four are to the motor and which one is for the right and left rail.

Thanks. Limey.

[richg]

Rather than assume, I got my multimeter out about three years ago and did a continuity check. The two pin is loco pickups. The four pin is, headlight and motor.

Rich

[Limey]

Thanks Rich,
                      The pins on my meter couldn't make contact inside the plugs.
  Can you remember which wire was for which rail in relation to the protrusion on the plug? 
         Since some of the other folks on this board have had trouble switching tenders, I was wondering if Bachmann was consistant with the wiring or if the pickup wires may be switched sometimes. It sure would be nice if the wires were standardised and colour coded.

[richg]

Thanks Rich,
                      The pins on my meter couldn't make contact inside the plugs.
  Can you remember which wire was for which rail in relation to the protrusion on the plug? 
         Since some of the other folks on this board have had trouble switching tenders, I was wondering if Bachmann was consistant with the wiring or if the pickup wires may be switched sometimes. It sure would be nice if the wires were standardised and colour coded.

No Bachmann has not been consistent. This has been discussed in the past but I don't have the links right now.
You could do a search in the General and HO sections but it will take some reading.
Realize when you work at this level, you have to know what you are doing. I have done electronics for many years so not an issue for me. I just consider it a challenge and this is model railroading.
The back of the plug has a spot for a meter probe if you look closely. I use a bare piece of #22 wire and clip leads with the meter probes.
When I bought the USRA medium tender for my low driver 4-6-0, the two adapters for the plugs, reversed each pair. I had to switch each pair in the tender and had to add a 1k resistor for the LED headlight. The two tender connectors are different.

I will have to look though my files. I checked the 4-4-0, and 4-6-0. Others here may have the info.

Rich

[richg]

This is what I found in my 4-4-0 that I hardwired a Tsunami Micro into.



Red is right rail and black is left rail.

I believe my 4-6-0 was the same. The 4-6-0 small driver had the small tender. To attach the USRA standard tender, I had to use two adapters that came with the tender but all three pairs where reversed which shorted out the DCC system since the loco pickups where shorted by the tender pickups being reversed so no damage to anything.



You can see a little slot to put your meter probe tip intp on the connectors.



Rich

[Limey]

Once again Rich, many thanks from me and no doubt many others on this forum.
A picture is worth a thousand words.

Regards, Limey.

[Tom M.]

Limey,

It is best to check every loco prior to starting work on them.  I just installed a Tsunami TSU-750 in a Richmond American 4-4-0.  I got lazy (because I had already done this to three other identical 4-4-0s) and simply attached the orange decoder wire to the PC board pad marked M+ and the gray wire to M-.  Of course, after I got the loco fully reassembled and on the test track I discovered the loco ran the opposite direction than normal.  It appears the factory had reversed the leads when they were soldered to the motor.  Doh!  Lesson learned again. Always take the minute to test.  It would have saved me 30 minutes.

Tom

[richg]

When you want to work at what I call the component level, have a couple millimeters and clip leads for testing and troubleshooting.
Below is what I have used for some years. The meters do not read AC current but have never found that to be an issue in model railroading.
The meters show about 13.7 VAC when running my NCE Power Cab DCC system. Agrees very well with my expensive meter and digital Oscope. I have three of the meters. Very nice when you want to measure DC voltage and DC current at the same time.

Generally the people who say these meters are not good for DCC don't use these meters.

http://www.harborfreight.com/7-function-digital-multimeter-90899.html

http://www.harborfreight.com/18-inch-low-voltage-multi-colored-test-leads-66717.html
IF, aa reading seeks doubtful, a second meter will usually verify. Happened to me once when one meter had a low battery and I did not take time to replace the battery when I should have. Lazy.

Rich