Connecting a TCS B-MB@ Decorde Board To My Bachmann Steam Engine

[starman5050]

Hello All

I am new to the forum and here is my first question.  A tech I spoke with from Bachmann could not answer my question but said perhaps someone on this forum could.  Thanks in advance for your help.  Here goes . . .

I am operating a Digitrax system on an HO layout.  I want to install a TCS B-MB2 decoder in a Bachmann Spectrum J Class 2 8 4 steam engine.  I have the decoder board and I know which color wires go to which pins.  All of the wires in my engine are black, but a Bachmann tech helped me identify which black wires are attached to which pins on the Bachmann 8 pin connector so I can now install the decoder.

My question:  On the B-MB2 decoder are two contacts, separate from the other contacts, for the backup light.  It is a bulb instead of a LED.  However, the backup light on my engine has two wires from the light that attach to the original Bachmann board, and two addition wires from two of the four copper strips on the tender that attach to the original Bachmann board.  What do I do with the two wires from the copper strips attached to the tender?  I only have two connections on my decoder to attach the backup light, but the original Bachmann wiring has four wires associated with the backup light on the original Bachmann board.  I'm confused!

Thanks for your help.

Jack

[jonathan]

Starlord, I mean, Starman,

Hopefully, I understand your description of the extra wires. So I could be wrong, but:

Bachmann tenders usually have two additional wires that come up from the tender truck pick ups.  They are right and left (+/-) track power inputs. And yes, the wires are usually black.  It should not be too difficult to trace the additional wires to the corresponding tender trucks. 

If you look for the black insulators on the tender wheels, you should be able to discern right and left pick ups for the wires.  These are to be added to the right and left pick ups from the locomotive.  Not familiar with your particular decoder, but you should be able to solder the tender pick up wires to the same tab where you solder the current pick ups from the locomotive.

Does that make sense, or did I make it worse? 

Regards,

Jonathan

[starman5050]

Hi Jonathan

Thanks for your reply!

The following site will show you the decoder I am using.  You can see that on the right side of the motherboard is printed Yellow (FOR).  This is where the two wires coming directly from the backup light are connected to the motherboard.  This is according to someone I spoke to at TCS.  When I look at my tender, I see two pickups on each end.  The pickups are wired so a front and back pickup on the engineer side are wired together and the front and back pickup on the other side of the tender are wired together.  A wire goes from each of the two front pickups and are attached to different places on the original Bachmann motherboard.

Are you saying to connect the two wires coming directly from the backup light to my new motherboard at the location designated Yellow, and the wires coming from the front pickups on the tender to the same location?

Thanks,

Jack

[jonathan]

Jack,

Didn't see the link to look at your decoder.  I have a link for you:

http://www.bachmanntrains.com/home-usa/dwg/dwgs/H821x-IS003.PDF

This is the diagram page for the tender.  Towards the bottom of the page is a pair of parts, "MTB33".

These are the brushes that pick up current from the tender wheels.  These have wires that thread their way up to the installed board.  It would appear there are a right and left wire for both trucks, so four wires.  These are current pick up wires that should be connected to the power input on your decoder.  If you get the link working, we can look and see.

You should solve this before you move to the reverse light.  Just a suggestion.

Regards,

Jonathan

[starman5050]

First, sorry for not actually including the link.  My bad.  Here it is

http://tcsdcc.com/Customer_Content/Literature/Motherboards/B-MB2.pdf

I see the MTB33 pickups both in the diagram and on my tender.  The rear pickups are connected to the front pickups and then the front pickups are connected to the original Bachmann motherboard.  My concern is where to attach the two wires from the front pickups to my new decoder board.

I hope seeing my new decoder board will help.

Jack

[jonathan]

OK I had a chance to study your new board.

All pick up wires need to be attach to the "track" inputs.  Both tender and locomotive pick up wires from the right side go onto the "Engineer's Side" Tab.

Both tender and locomotive pick up wires from the left side go onto the "Fireman's Side" Tab.  It is important in DCC to have as many wheels providing current as possible.

You have two sets of tabs for the lights:  "FOF" tabs are for headlight, "FOR" tabs are for reverse light.  You will need resistors if the lights are LEDs.

Warning! I have enough knowledge to be dangerous, but not enough knowledge to be an expert.

Regards,

Jonathan

[starman5050]

Hi Jonathan

Thanks for all of your time and help with my little project!!

To be sure I totally understand what you said, I should connect one of the wires from the tender pickups to one of the track tabs and the other wire from the tender pickups to the other track tab.  With this being digital, I'm guessing it doesn't matter which wire goes to which tab.  Does this sound correct?  Perhaps I will be able to actually see and hear my engine operate today.

Thanks,

Jack