Pictures and Diagrams

[Yampa Bob]

You've heard it often: "A picture is worth a thousand words". I'm starting a new project that hopefully will allow members to answer questions with a minimum of explanation.

1.  DO copy the images to your computer for your personal reference.
2.  DO upload the images to your personal hosting site if you wish to post them in other threads, (this board only) and maintain the original dimensions and file size.
3.  DO NOT link directly to an image at my Photobucket album. For one thing the image might not be there indefinitely.

Images will include Bachmann Spectrum 2-8-0 UP, medium USRA and Vanderbilt tenders, Bachmann GP40 / GP35, FT/A-B, GE 70 Ton, and GE 44 Ton, each with 2 or 3 views and as much documentation as possible on the image.

Comments and suggestions are welcome, each time I add new images, I will condense the thread to the basic content. For uniformity, only my personal pictures and diagrams will be included in the updates, however I will consider suggested revisions.

Here is the first set, USRA Medium DCC ready tender.

Disclaimer: All references to wire colors are based on my models, and may not be consistent with other models. The only consistency is the inconsistency.

Pictures and diagrams are Copyrighted. Posting is limited to this board only. 

[richG]

HI Bob

Very good. I like it a lot.

What are your camera settings and light sources?

What is the material for blue background?

What photo application do you use?

Font sizes?

Thanks.

Rich

[Yampa Bob]

Note to Rich: I answered in a previous post (now deleted). If you missed it, let me know.


In regards to the USRA Medium DCC ready tender #89731, I installed a Bachmann decoder borrowed from a Vandy tender. Direction was ok, but the headlight stayed on full bright, in either forward or reverse. Jim Banner references the issue on this page:

http://www.members.shaw.ca/sask.rail/dcc/2-8-0/index.html

I removed the board and spliced the wires to a NMRA 8 pin socket harness obtained from Litchfield. The harness is "Loksound #51950 adapter cable".

I am curious if the current release of #89731 has been upgraded.

[Yampa Bob]

At this point I want to re-emphasize that there is no consistency in wire colors. However there is some degree of consistency in the "Pin-outs" for the connector at the front of the tenders.

Referring to the top view of the USRA Medium tender, starting at the top of the 4 pin portion and working down:

1.  Motor Plus (+) (usually red, but 1 vandy has violet)
2.  Motor Minus (-) (usually black, but 1 vandy has gray)
3.  Headlight Common (+) (various colors, blue found on one)
4.  Headlight (-) (various colors, most common yellow)

On the Vanderbilt tender, the connector is oriented opposite, so the pinouts would start at the bottom working upwards.

The two pin connector is locomotive pickup power in (input), with red for right rail, black for left rail. For the connector above, red is on top, black underneath. For the Vandy, the black would be on top. These colors may also vary, but have been consistent on 3 USRA Medium and 4 Vanderbilt in my roster.

[Yampa Bob]

As some may recall from a previous thread, I fashioned a "Power Stick" consisting of two .015 PB wires, attached to a stick and wired to a DC pack. By inserting the wires into the mating connector on a Spectrum 2-8-0, I verified the pinouts as described.  It happens that .015 is the perfect size for jumpers to run the locomotive without a tender.

1.  Motor Plus (+) (expecting red, but is brownish-gray)
2.  Motor Minus (-) (expecting black, but is red )
3.  Headlight Plus (+) (orange)
4.  Headlight Minus (-) (yellow)

When I split the castings, I noticed the Connie already has an LED installed, confirmed by reversing the polarity. The supplied Vandy tender has "LED" marked on the PC board.

[Yampa Bob]

For the medium Vanderbilt tender, I feel no need for a bottom view. All bottom details shown on the USRA Medium, including wheelset orientation, apply to the Vandy, with one exception.  Two screws hold the upper shell on, one in the middle and one in front of the front truck. The front screw can be removed without removing the wheelset.

I also found no "variant" in the wiring to the tender truck pickups. From the locomotive pickup "input" terminals on the PCB, a red wire leads to the front truck, a black wire to the rear truck. The top view shows significant differences in the PC board. 

The Vandy tenders that came with my 2-8-0 UP won't work with Digitrax decoders. Not wishing to modify the PCBs, I shall run them with the factory supplied decoders until they fizzle, then hard wire a new decoder.   

This concludes the wiring schemes for the two types of tenders I have in my roster.  The next segment will be on the Spectrum 2-8-0 pickups and wiring (partial noted above) which will take some time. 

(Intermission)  

[richG]

Hi Bob

I see you said the USRA tender is used with the 2-8-0. Where is the resistor for the headlight? The tender and loco configuration must be a little different than my tender. The photo of yours looks the same as mine. My tender comes with a two pin and four pin adapter with short wires to plug into my 4-6-0.

I just opened up a new USRA tender to use with my 4-6-0. I dug out a LED to use as a sacrificial lamb to check the PC board. The LED blew out. With a 1k resistor, and with another LED. the light was good and 10ma current.

I traced out the circuit and there is a 120 ohm resistor with four diodes, plus the caps and coils. The socket on the PC board is configured so the headlight will never go out in reverse. Both pins 2 and 6 connect to the LED via diodes. You would have to break the PC board trace going pin 2 or do not connect the reverse decoder wire to the NMRA plug.. I plugged in a DSD-100LC decoder to verify all of this.
I will have to change the connections to the four wire connector as the polarity is reversed on the motor and headlight pins and add a 1k resistor.

Rich

[Yampa Bob]

I don't have the eyesight or patience to modify PC boards, and shouldn't have to.  When I buy anything "DCC ready", I expect it to be plug and play, and I'll wager that most new modelers feel the same way.  For the price we pay for these things, one shouldn't have to cut traces, clip capacitors and coils, or otherwise rebuild the board.

[db22]

Yampa Bob, I agree with you but a lot of people in MRR "tinker" and a lot of the tinkerers have electronics knowledge. I understand electronics too and I would not mind cutting traces but for Bachmann not to give us the PC layout, schematic and parts list is inexcusable. I seen very complex boards reverse engineered, sometimes just to **** off the manufacturer, but in this hobby it seems that the manufacturer would only benefit by helping their customers. Tracing the board is futile and Bachmann knows that we can do it so why not help us instead of hinder us?

[Yampa Bob]

db22,
Understand I am not the type that expects out of the box performance. Most of the members know I fine tune all my trains, and do my own repairs, but due to age and other factors I am not up to the challenge of modifying PC boards.

As for the Vanderbilt tenders, I can live with the Bachmann decoders as supplied. However, if the boards aren't compatible with other brands of decoders, then as you mentioned, they should furnish schematics and instructions to make the modifications.

The USRA Medium is another issue. The ones I have won't work with any brand of decoder, not even Bachmann's.  Obviously the internet dealer had a bunch of old stock and dumped them on me.

I just talked to Bachmann service, they will gladly replace all the  tenders, with the caveat that I might receive the same older versions in exchange. The total cost to me would be $135.00 in fees and shipping.  For that I could buy 4 current release tenders.

I am expecting a return call from service later today regarding this matter.

[pdlethbridge]

What a bummer. They have got to address the standardization of their tenders otherwise a lot of customers will be lost. Product support, I think, is very good. It took about 2 weeks to send in and get back my DOA decapod. If the problems in manufacturing were addressed, there would be no need to return a NEW product for servicing or replacement.

[db22]

Bob, so the tender AND the loco pick-up the power and are connected via the 2 pin connector? The tender then sends the decoded power to the loco led and the motor via the 4 pin connector? If my thoey is correct then it would probably work with the 2 pin connector unplugged but it doesn't. What am I missing here?

[Yampa Bob]

The idea is "you can never have too many pickups". On a seamless track, you could run the loco with the 2 pin plug not connected since the tender also picks up power from the truck axle wipers. But going through turnouts and such, you might lose power without the extra loco driver pickups.

If the tender pickups are only contacting intermittently, the driver pickups will fill in the power gaps.  Decoders like smooth and constant power, brief "break and make" power inrush surges (and shorts) can confuse the little critters.

If you notice in the Vandy picture, both the loco pickups and tender pickups are connected to the "input" terminals. If your loco won't run at all with the 2 pin connector unplugged, you probably need to rebend the tender axle wipers a bit for better contact. 

[db22]

Thanks Bob, that's the  way I read it but when it did not run with the 2 pin unplugged then I started to doubt my theory. So now I think that I will splice into the loco pick-ups to a 2K R and put a red glow in the firebox.

[Yampa Bob]

Personally, I don't recommend splicing into the loco pickup wiring for any auxiliary lighting effects, remember the rails are supplied with full "AC" power at all times, and the decoder relies on uninterrupted and unfluctuating power. You also run the risk of producing a short in the feed wires to the decoder, or creating other problems.

Some decoders have separate functions for ditch lights, Mars lights, firebox glow, etc.

For on board auxiliary lighting, I would consult with Jim Banner or others with knowledge and experience with these applications, but that is beyond the topic and scope of this thread. Other than the tender compatibility issue, I am mostly concentrating on the "Electrical" aspect of wiring for the purpose of troubleshooting. 

Perhaps Jim or someone else could start another thread on auxiliary lighting functions if there is sufficient interest in such.