Bachmann Online Forum

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. 

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

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

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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.

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.

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.

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)   8)

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

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.

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?

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.

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.

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?

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. 

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.

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. 

As mentioned in my opening post, and in response to requests, I am preparing a pictorial for complete disassembly, repair and reassembly of a Spectrum 2-8-0, along with a few modifications for easier servicing and testing. The task requires small metric nut drivers which I have on order, and some time to make up documented pictures.

Meanwhile, for those wishing to hard wire decoders in the tenders, I offer a couple of ideas to make the install neater, with a bonus of being able to use probes for testing.


I cut off all extra nylon to make them small as possible. Strip off about 5/8" of  insulation, twist wires and fold over, tin with solder before inserting into connectors.

Here are micro-sized terminals for a custom PC board, available with 6,7, or 8 connectors.

http://www.ebyelectro.com/terminal-block-product-info.asp?ProductID=85

I got a bunch of connectors here that are about 1/3 smaller, .1" center spacing.
http://www.futurlec.com/ConnPolHead.shtml (http://www.futurlec.com/ConnPolHead.shtml)

I just installed a Bachmann decoder in my DCC ready Decapod. (The Decapod is DOA but that is another thread.) I had some dual in-line headers (DIL) for 16 pin IC's and cut them with cutters to 2 single in-line 4 pin headers. Spacing is correct and they worked fine but the coal lid on the tender would not go on properly. The plug has to be very low profile with the wires coming out of the side for the lid to go on so I trashed the idea and soldered the wires directly to the socket.

I obtained current versions of the USRA Medium DCC ready tenders. The PC boards appear to be "3rd Release", as used in current models of  DCC equipped Spectrum 2-8-0.

First release PCB is shown in the opening post.
Second release PCB had 2 resistors and 1 diode added.
Third release does not have the resistors or extra diode. 

I tried both Bachmann and Digitrax decoders, with the tenders coupled to my Spectrum 2-8-0. The main difference noted was a smoother startup and more linear throttle response with the Bachmann decoder. I suggest using only Bachmann decoders with these tenders for optimum compatibility.

Due to a question regarding motor wiring in another thread, I have repeated my reply in this thread as a prelude to the Spectrum 2-8-0 tutorial.

---

A permanent magnet DC motor has no electrical "polarity", only the magnetic polarity of the internal magnets.  In other words, the motor has no specific positive or negative terminals.  Read on please. 

By convention, shaft rotation on small permanent magnet motors is stated as viewed from the brush end (rear) of the motor, either clockwise (CW) or counterclockwise (CCW) rotation.

The presence of a red dot or plus sign on a new motor simply indicates that the positive lead connected to that terminal produces the rotation as specified by the motor manufacturer or the factory producing a motorized device, typically CW, but may be CCW depending on the maker and the application.
 
The Spectrum 2-8-0 uses direct drive. By that I mean there is no intermediate idler gear.  The worm gear is "right hand", just like a right hand thread on a bolt, and since the motor is positioned with the output shaft to the loco rear, the shaft must rotate CW for forward motion.

If a motor is positioned with the output shaft forward and is direct drive, then the shaft will rotate CCW for forward motion.  (So far I have found no markings of any kind on my Connie motors.)

Bottom line, wire the motor to achieve proper shaft rotation. If loco direction is wrong, then switch the wires. Here is a flash animation everyone should view.

http://www.mabuchi-motor.co.jp/en_US/technic/t_0102.html

Why the confusion?  Using a decoder as an example, the orange wire is labeled "Motor Plus".  The "plus" is not referring to the motor terminal, it means "this is the positive lead, when the controller direction is set to forward motion...... connect it to the motor terminal that results in proper direction"

If you had previously marked a motor terminal as "+" because the orange wire was connected to it, and you had correct direction, then the orange wire would be reconnected to the marked terminal.

You should always confirm proper shaft rotation before re-assembling locomotive.

This should have been included in an earlier post, but due to visual problems I admit to being a bit disorganized these days.

I found an "Important Notice" packed with one of my Spectrum 2-8-0. The notice has not been included with any of my other Connies. Thinking that others may not have seen the notice, I shall include it here: (quoted exactly from the notice).

"In accordance with strict international electronic emission regulations, Bachmann locomotives are equipped with suppression capacitors and inductors (RF chokes) to reduce interference with radio and television signals.

NMRA conformant DCC decoders,including Bachmann E-Z Command decoders, will work properly with these capacitors and inductors, but these components may cause a malfunction of decoders that do not conform to NMRA standards.

To prevent damage to locomotives equipped with decoders that do not meet NMRA standards or are not part of Bachmann's E-Z Command line the suppression capacitors and inductors (RF chokes) on this locomotive must be removed from the circuit board before non-NMRA decoders are installed."   (end quote)

For the reasons stated, I now use only genuine Bachmann decoders in Bachmann locomotives. (or Soundtraxx sound decoders, which I have been informed are compatible with Bachmann circuitry).

Tne notice was "Printed in China", so the warning should probably have read: "To prevent damage to (Bachmann) locomotives (by installing decoders) that do not meet......etc".

THIS topic is a life saver!

Thank you, thank you, thank you!

Seeing Yampa Bob's name in the post is a blast from the past. He was a wealth of knowledge.

Yeah, I found this completely by accident, and it answered a LOT of questions I had on DCC, and installing a decoder! I'm looking at a couple of DCC ready engines, and was worried I wouldn't be able to install a decoder, but this thread eased my concerns a bit.

What type of topics can be posted here, what things we can post in off-topic boards?

Not needed

Rich......why are you replying to 3+ year old threads?

Sid

Quote from: Molly877 on September 30, 2020, 12:26:55 AM
What type of topics can be posted here, what things we can post in off-topic boards?

And to answer your question....read this link.

https://www.bachmanntrains.com/home-usa/board/index.php/topic,8493.0.html (https://www.bachmanntrains.com/home-usa/board/index.php/topic,8493.0.html)

Sid

Oops. I saw it pop up behind Mollys post. It was middle of the night. I was up and bored. I will remove it.  Never noticed the date. I was surprised to see the post by Molly again.

Rich

I guess MMR refers to "Master Model Railroader," a certification obtained via the National Model Railroad Association (NMRA).  Almost as many abbreviations as in the government.  I am curious: do any of you MMR's use digital scopes to troubleshoot these issues or is everything done via a multimeter?

Welcome.

You are in a very old discussion. You should start your own discussion. I made the same mistake. It is called hijacking a discussion.

Rich