Mr. Bach Man? What are the components of the N2-8-0 Spectrum light PCB?

[SandyEggoJake]

I'm in the process of designing lighting mods to the Bmann Spectrum N2-8-0 (DCC ready).  So I'm attempting to figure out the components of the stock PCB02 (811xx-N81101).  Later I intend to add DCC & sound.  But the first step is to understand. 

The easy part was the resistors:  the three SMD 682 are all 6.8kOhm.  But the specific specs of the stock zener diode and the LED (845xx-10080) are both a mystery.

Bach man, can you provide a bit more details on this PCB02 than are available in the online diagram or the package insert? 

Cheers!  (Big fan of the Connie - I already own 5 and looking for more).

[the Bach-man]

Dear Sandy,
I have no idea, but I'll see what I can find out next week.
Have fun!
the Bach-man

[SandyEggoJake]

Any update yet?

[Bucksco]

I do not believe you will find the information you are looking for here on the forum. Perhaps a call to the service department would be a better alternative.

[SandyEggoJake]

After 3 emails with Bachmann I still don't have an answer.  They've been helpful and gracious ...  but so far not useful. 

In their latest reply to my request for the specs on the three components they used in this board, they finally admitted "they might only exist in some Chinese factory somewhere".  My guess?  The Kader group's Dongguan, China plant.  But Bachmann Part Dept was kind enough to provide me two gratis PCB so that I could "mess around and see what they come out at".

Ok,  thanks... but seriously? 

So now I either need to build a logic board that can determine the zener's breakdown voltage (see http://www.instructables.com/id/Build-a-Zener-Diode-Identifier/step2/Identifying-an-Unknown-Zener/).  Or more likely, just scrap the whole Bachmann headlight board and design my new lighting package denovo. 

[Old John]

Jake,

You may want to try your question at the N Scale Forum, as they have a lot of folks that are always "tinkering" with lights

http://www.nscale.net/forums/content.php

[Bucksco]

Something that you need to keep in mind is that the PCB is not manufactured in Philadelphia thus the spec sheets do not reside here. The service department is limited in the regard to the information that you are looking for and quite honestly does not usually need to provide such information. 

[Mike C]

 I blew the LED on my 2-8-0 when I replaced the factory decoder board .  I just replaced it with a new LED and a 1000w resistor .

[SandyEggoJake]

Thx All.

Mike C: Your LED + resistor may work... at least for a while. 

But understand your replacement circuit has no zener diode, and thus no voltage regulator (unless your new DCC board provides a voltage regulation for its lighting circ).   Without a voltage regulator, at high speeds, your LED may see too much current - leading to significantly reduced life - and at some range in lower speeds (at least in DC and depending on your circuit in DCC) the brightness of your LED may be a function of the same current fed to the motor, and thus your bulb will emit variable brightness. 

The lighting mods I'm designing include additional functions toggled with DCC ops.  Namely both a) reverse headlight dimming along with an added backup tender light, and b) constant brightness circuit for additional light features being added.  Was simply exploring it the stock PCB could be used.

[Mike C]

 The 1000 ohm 1/4 watt resistor will protect the LED from the high DCC current . Brightness stays the same over the full range of speed .  It's a commonly used system as far as I know .