Strange Circuit Board in Spectrum Tender

[rrinker]

 That is a typical Bachmann lighting board, with what looks like a 6-pin EUN connector for DCC. Probably for a newer version of the same or simialr loco to what you have - they old production version with no circuit board is no longer available so they gave you a new one to satisfy the warranty. Perhaps the 6 pins were simply to prove a way to connect the wires to the motor and lights, since EUN decoders have the 6 male pins on them, not a socket. In addition to the diodes for directional lighting, there are 2 coils (those tubes ont he bottom) and a coupel of capacitors on the top side. Bachmann uses these to reduce RF emissions, and while they work fine for straight DC, when they are int eh circuit for a typical DCC decoder which uses PWN, or in Sheldon's case with PWM power provided by his Aristo DC system, it interferes with the signal and causes erratic running. That capacitors are generally parallel with the motor and can be simply cut out, the choke coils are usually in series and have to be jumpered around, although satisfactory operation usually results from just removing the capacitors.

                                   --Randy

 

[ATLANTIC CENTRAL]

Again, I can only go by my HO experiance with Bachmann but their circuits boards usually contain all three things, DCC interface plug, DC directional lighting and capacitors and inductors to prevent radio interference.

A search of this board will find a thread I posted about disabling the radio interference filters to get better slow speed performance with DC throttles. Additionally many DCC users find it necessary to remove the radio filter capacitors as well for proper decoder operation. Many HO modelers I know remove the Bachmann circiut board completely when installing decoders.

Again, compairing to their HO products, if I buy a new DCC/sound or DCC 2-8-0 it has one circut board in the tender, BUT if I buy the seperately offered version of that tender it still comes with the orginal design circiut board from the first run of 2-8-0's many years ago. this could well be the case with the N scale products too.

Hope this helps.

Sheldon

[richg1998]

 That is a DCC interface board. There are the coils and capacitors for filtering the DCC signal that goes to the motor. Also, four diodes. I have seen the same components in my HO Spectrum's.

Bachmann has known issues with stand alone tenders in the HO versions and differences between different locos and tenders. Do not know about N scale.

Go to the Bachmann forums and ask.

http://www.bachmanntrains.com/home-usa/board/index.php

Rich

[tbdanny]

Thanks for the quick reply, but I don't think this is the case.  The tender this appeared in was sold as a stand-alone tender, independant of the locomotive.  And the N scale version of the consolidation has space for the DCC decoder inside the boiler.

I'm guessing it may be something to do with radio frequencies & interference - can anyone confirm/deny this?

[ATLANTIC CENTRAL]

While differet in appearance from the ones in HO that I am familiar with, this circuit board is for the directional lighting and acts as a wiring point for DCC. It may be different from other you have seen as Bachmann has changed/upgraded the designs over the years.

Again not being in N scale I cannot speak to specifics as to why it is different from you old one.

Sheldon

[tbdanny]

Hi,

I just received a replacement Spectrum N scale USRA Medium tender, to replace one I botched in an attempt to install DCC sound.  When I put this tender on the track, I heard a faint buzzing sound, like the sound coming from a DC motor on a DCC signal.  I determined that this was actually coming from the tender and not the loco.

Opening the tender, I found the following board inside:

Top;

 

Bottom;

 

As you can see, I've removed it.  The loco is working fine and the buzzing is gone.  However, I am curious as to what this board does.  Can anyone shed any light on this?

Thanks,

tbdanny