# K27 battery and sound questions



## placitassteam (Jan 2, 2008)

I am installing battery power and sound using Dell's (G-Scale Graphics) Rail Boss with a SpectrumD6 RC and Phoenix P8 sound in my Bachmann K27. A search answered some of my questions but I still have some. I am removing the electronics in the tender but plan to use the existing boards in the loco to power the IR chuff, lights, except the headlight, fire box flicker and the fan, and the smoke if used. I plan to install the Rail Boss and P8 in the loco so as to have only 4 wires between the loco and tender, 2 for power and 2 for the speaker.

The functions at the wires on the large board in the loco which go to the tender connecters p6 and p7appear to be as follows;

6p
A yel o aux pwr
B wht o fire box
C blk o marker lites
D gry o chuff +
E orn o front lite
F red o chuff -

7p
7 pur o rear lite
6 yel o Bat -
5 wht o Bat +
4 blk o right rail -
3 gry o motor -
2 orn o motor +
1 red o right rail +

Questions

1. Should I connect full battery power to Bat +(7p-5) and -(7p-6) on the large loco board?

2. How do I do the chuff trigger to the P8? Should I run the chuff +(6p-D) line to the C2-2 pin (chuff) on the P8 board? Should chuff -(6p-F) go to the C2-1 pin (Trigger ground)?
I think those are the only wires from p6 and p7 that I might need to use.

3. Should full battery power connect to pins C1-1 and C1-2 on the P8 board and motor power go to pins C1-6 and C1-7?

I would very much appreciate any help that I could get. Thanks


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## Greg Elmassian (Jan 3, 2008)

Have a look here 
http://elmassian.com/trains/motive-power-mods-aamp-tips/bachmann-motive-power/k27 

Links to schematics 

Greg


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## placitassteam (Jan 2, 2008)

Thank you Greg, In your write up you say here is an unofficial schematic but nothing appears in that space. I have both the schematic and wiring diagram that you provide links for but am having some trouble determining what is on which board and which wires are which. Maybe I just need to stare at them some more. My main concern is that I not hook something wrong and destroy the sound board.


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## Greg Elmassian (Jan 3, 2008)

I'm going to give you a piece of candid advice, and don't take it personally as an insult: 

You should have never removed the electronics unless you either have someone wiring it for you, or you can easily understand the schematics and figure out the wiring. 

Asking for a cookbook solution without actually understanding is dangerous, and many people won't respond for fear of being blamed later for helping you destroy your loco. 

At this point, 50% of the people I say this to are po'd and say "I only have a couple of questions to be sure".... my response is reread the previous 2 sentences. (It's always perceived that there are only a couple of questions). 

Basically, if you feed the power where it used to go you would be fine, and you should read up on the chuff stuff to see what the tricks of the chuff circuitry are. 

Maybe someone else will step up and give you specific advice, and be more "friendly", but in the long term, my advice will also allow you to maintain your loco and repair it when something goes wrong. 

Read my site on the chuff stuff, and some more adventurous individuals can and will help you better. 

best regards, Greg


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## East Broad Top (Dec 29, 2007)

You're close on the wiring: 

7 pin 
1 - right rail 
2 - motor + 
3 - motor - 
4 - left rail 
5 - Batt/DCC + (common power for all lights and smoke) 
6 - Ground 
7 - Smoke - 

6 pin 
1 - chuff - 
2 - front light - 
3 - optical chuff (second chuff sensor) 
4 - cab light 
5 - class (marker) light 
6 - firebox light 

I can't tell you colors, because I'm looking at my tender and the colors are different from what you describe. 

Since you're installing everything in the loco instead of the tender, you needn't worry about too much of this. You're going to want to isolate the motor leads and wire them directly to the output of the RailBoss. That will bypass any noise suppression which you don't need anyway. Battery power (from the tender) will be hooked to the "right" and "left" wires on the 7-pin side. I don't believe polarity matters, but check the instructions on your electronics. You'll connect the battery power to both the RailBoss and P8 per those instructions, and the motor output of the RailBoss will get run to the motor and to the motor input on the P8, again per its instructions. Phoenix's web site has good wiring diagrams to help you. 

What you won't have is power to the lights, smoke, or fan at this point in the game. For that to work, you'll want to hook B+ to the wire coming from pin 5 on the 7-pin plug. The Bachmann wiring uses a common + feed, and all the switches then close to ground. You don't mention whether you want to remotely trigger these features (nor do I recall if the Railboss has that capability.) The switches in the smokebox will allow you to turn these features on and off. If you don't want to remotely control them, just set the switch to "on" and they'll be on whenever power is applied. Or you can physically connect the cab, firebox, and class light - leads to ground to do the same thing. If you want to remotely trigger them, hook the appropriate wire to the output of the trigger on the RailBoss. You'll want to do that for the headlight if you want a directional headlight, otherwise just connect the headlight- to ground as well. The fan should take its power automatically, so you shouldn't have to do anything with that (presuming you want to use it; it's proven to be optional.) 

The wildcard is the chuff. The optical chuff on the K is "backwards" from what most sound systems need, so if you want to use them, you'll have to wire in an additional circuit. The diagrams I've seen show how to do that on the "dummy" board in the tender, but not physically within the locomotive. Personally, I'd just install a magnetic reed switch near the rear axle and glue 4 magnets to the drum on the axle. Far simpler. 

A few thoughts... 

If you've got a back-up light on the tender, you're going to have to run additional wires to that, so you're up to 6 wires running between loco and tender. At that point, you're using all the wires in one plug already. Why not just use both and keep all your electronics in the tender where they're far easier to access? You can chuck the socket board easy enough and just use the wires coming from the plugs. I'm not a huge fan of taking boilers off locomotives, no matter how "easy" the manufacturers make it. If the electronics get screwy, it's a lot easier to just pull the tender shell to investigate. The wiring instructions stay the same no matter where, but in terms of maintenance, it's just 500% easier to get into the tender. 

Later, 

K


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## placitassteam (Jan 2, 2008)

Thanks Kevin, I think you have pretty much answered my questions. I think I will go with the magnet triggers for the chuff. I will be using the switches in the smoke box as you mention. I do not have a back up light and wil rarely if ever use the smoke. The only reason I bought this loco is because I couldn't afford the Accucraft Live steamer! Most of my other engines are live steam and in my opinion easier to deal with. I have them all RC'ed and let them make their own sounds. Thanks again, Kevin. I can take it from here.


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## Treeman (Jan 6, 2008)

I would defiantly agree with doing all of the work in the tender. The beauty of these is all of the needed points are in the tender. And their is some room for components.


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## TonyWalsham (Jan 2, 2008)

Rather than ripping everything out I would leave the wiring exactly as it comes stock and modify the dummy plug only. Just make a couple of simple cuts to the traces on the dummy plug, add a couple of wires and the Rail Boss can be installed just like a PnP ESC.
There is plenty of room in the tender for lots of batteries.
Connect the battery to the marked terminals on the socket pcb and set the track - battery switch to battery. Unlike the (so called) track - battery switch on Aristo locos, the Bachmann switch completely isolates one from the other.
Modifying the chuff signal is very simple too. One small cap and an open collector transistor soldered to the main PnP socket will enable the loco chuff timers to work with pretty well any sound system.
I have done dozens of K-27's and never had a wiring failure or chuff timer failure. What is more the wiring in the K-27 is consistently the same from loco to loco.
Unless you particularly want good smoke I would leave the fan alone. Removing the boiler is easy enough but getting it back on can be tricky.


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## Del Tapparo (Jan 4, 2008)

Thanks to all that have provided great info and advice to Winn. Having never worked on a K-27, I can't really pitch in here. I would agree with keeping everything in the tender. And just for the record, the RailBoss does provide directional lighting outputs. The front headlight is also used to give operator feedback during startup and programming. Good luck with your install Winn !


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## Greg Elmassian (Jan 3, 2008)

If it was not clear from my post, I'm 100% in agreement with Tony. So many times I have seen an eager battery-phile rip out all the electronics (with gusto!) and then have problems wiring. In the K, there are more complicated "interfaces" than just bulbs and a motor, there are current limiting resistors for the LEDs, the circuitry for the chuff, etc. The loco was designed to be simple to interface to without disemboweling it! 

Regards, Greg


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## TonyWalsham (Jan 2, 2008)

The following might be useful for those users who want to install a non PnP ESC in the Bachmann K-27 without making any wiring changes to the loco.
This pic shows where to cut the four traces on the dummy pcb.










Next pic shows where to hook up the wires that will be going to the non PnP ESC.
You can remove the RF chokes if you wish to and solder the Grey (Motor -) and Orange (Motor +) wires direct to the appropriate motor pins. I chose not to remove them even though they are not necessary with 2.4 GHz R/C. They can be quite safely left in place and will assist with motor "noise" suppression if the R/C being used has short range.

The wiring legend is thus:
J1 1 Black Battery Ground (-)
J1 3 Grey Motor (-) via the RF choke.
J1 4 White Front Light.
J1 9 Yellow Rear Light.
J1 10 Orange Motor (+) via the RF choke.
J1 12 Red Battery Positive (+).

Set the TRACK - BATTERY switch to BATTERY, and the POLARITY switch to NMRA.










These instructions are now included with my *RCS BIK-K27 installation kit *


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## placitassteam (Jan 2, 2008)

Thanks to all of you for your help. I guess I'll have to think some more about putting all the electronics in the loco. I just don't like all those wires running to the tender and the connectors are such a bitch to unplug. I know I could build a case that carries both the loco and tender hooked together but that is such a beast to handle! I'll keep you posted on what I do but probably not with with photos since my first class was teminated without warning or notice and I no longer have a place to put photos and have lost all the ones that were on the MLS site.


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## East Broad Top (Dec 29, 2007)

Remove the clips on the plugs that keep them plugged in. They're not going to work loose during normal operation, so no worries about that. When you're done running, a gentle tug is all you need to pull the plugs apart. It's a lot easier than Accucraft's #%$&*! water line connectors.  

Later, 

K


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## TonyWalsham (Jan 2, 2008)

..............and, don't forget to put a smear of silicone adhesive around the wires at the point where the plug wires actually enter the plugs. This prevents the wires flexing at the plugs and breaking. 
Yes I know there is a strip of rubber there already. The silicone just adds to the security.


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## Michael Glavin (Jan 2, 2009)

FWIW:

IMO and others using some silicone rubber type adhesives is detrimental to your electronics health, a Google search will provide more in-depth thoughts on the silicone and electronics phenomena.

That said the right silicone based products are great for the various needs herein. I use shoe-goo, PFM and similar products generally as they don’t incorporate acidic properties and are great for many other uses and modeling considerations.

Michael


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## TonyWalsham (Jan 2, 2008)

Agreed Michael. 
I only use a non metallic content and non acidic silicone roof and gutter sealant made by Selleys. I have never had any problems gluing electronic components to insulated surfaces. In fact, if anything coating the pcb's with that particular adhesive prevents any corrosion build up.


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