# DCC AND BACHMANN K27



## daveyb (Feb 28, 2009)

hope someone can help me,,,,

im thinking of going dcc when i build my layout next year,,, 

i have 2 bachmann k27s and im looking to get them ready for use,,

can anyone recomend a decoder for the k27 , is the digitrax dg583ar any good and will it plug in

without any messing about,,,, 

im looking for good slow speed running and id like it to chuff when it should and not run away down hills,,

and what sound card will work best with these engines,,, i have a pheonix 2k2 in a k28 which 

sounds great and runs great and thats the quality im aiming for, this will also need a decoder,,


all sugestions welcome

daveyb


----------



## East Broad Top (Dec 29, 2007)

I've got one here that I'm working on that's got a QSI Magnum installed. Great sound and control. Plug and play, also. I think there's some incompatibility with the K-27's optical chuff (I'm on a limb there) but my understanding is that the BEMF-controlled chuff renders that a moot point. I didn't do any of the programming on this particular decoder, I'm just doing some cosmetics on the loco. 

Later, 

K


----------



## jimtyp (Jan 2, 2008)

This is from another thread on the B'mann K-27: 

... 
You asked about DCC use. QSI and ESU have DCC sound boards that plug into the socket. The ESU board supports all the functions including sound with no modifications. The QSI board requires a simple inversion transistor should you wish to use the on board chuff circuits rather then the boards auto chuff feature. There is one chuff sensor in each cylinder triggered at the half way point. 

... 

Here is the full thread:  b'mann K-27 Thread


----------



## Greg Elmassian (Jan 3, 2008)

By the way Kevin, your lighting difficulties were caused by blown transistor "switches" for the lights, they often short so the light is always on... they are the small 3 terminal SMT devices on the board if you trace the wires from the lights. 

I would also recommend the BEMF chuff, as the optical sensors are not at the limits of the piston travel, properly set, the BEMF chuff is great, and it's easy to set. 

Regards, Greg


----------



## steam5 (Jun 22, 2008)

There has been a huge amount of discussion on the K-27 and the function of the socket, and how plug and play the locomotive actually is. Search for ‘Bachmann k-27’ or even try Googling "Mylargescale Bachmann k-27’ I some times have better luck searching with Google.

I actually think I saw some documentation on the Digitrax web site on how to connect there decoded to the socket?
If your going DCC, the Phoenix P5 is a great choice if you liked the 2K2, and its cheaper!


I have a K-27 running on DCC successfully. I haven’t got round to connecting my Phoenix sound car in yet, but that will be easy as I have abandoned the Bachmann optical chuffs for a reed switch I installed.

If you’re okay wire wiring things I would considered stripping out all the Bachman electronics and starting again. This is what I did, and it work well and did improve some aspects of running the locomotive. But I think striping it will void your warranty. 

If you don’t want it to run away down hills you will need back EMF, I think the Digitrax decoder has this? I used a Lenz gold maxi and the BEMF works great on it.

Good luck with the install. Some of my comments are a bit off topic; I hope I haven’t confused things.

Alan


----------



## daveyb (Feb 28, 2009)

thanks chaps,,,, 

i have no probs with pulling all the wires out,,, in fact i think thats the way forward, is there any info posted or diagrams out there to follow specific to rewiring, can i use my k28 as an example to follow,,,, i would like to keep all the lights etc 

think im going to follow in alans footsteps and pull it all out!! 

and where do you get the reed swiches from, 

thanks everyone 

davey b


----------



## East Broad Top (Dec 29, 2007)

Greg, the lighting issues with the stock Bachmann board revolve around the lights not coming on at all. (This was with the Aristo Revolution board plugged in.) Everything worked fine on regular track power, but nothing with the Aristo board plugged in. That's what prompted me to try the small adapter board that came with the Aristo board in lieu of the stock B'mann board. That small board only has two diodes on it. One of them may be fried, but as I said, it's a rather serendipitous situation, so I'm not complaining. 

Davey, I hear you on ripping things out. That's what I ended up doing on my K-27. The good news is that the existance of the socket means all the wires are right there nice and handy for your DCC installation. I hard-wired the cab light and firebox to be on all the time, and assigned the headlight and front class lights (aka "markers") to separate controls, so I can run them independently. The rear light is directional, via the Revolution board. 

Later, 

K


----------



## SteveC (Jan 2, 2008)

I don't know if this will be of any use or not but back when the Bachmann K27 came out Bob Grosh made two drawings of its electronics and wiring. Don't know if these still hold true for present day production, but here are links to those drawings.

K27 Drawing 01[/b]

K27 Drawing 02[/b]


----------



## Greg Elmassian (Jan 3, 2008)

Kevin, I guess I misunderstood... I thought you posted somewhere that one of the lights came on and stayed on. That is one of the typical indications of a blown transistor. Of course the other indication is the light not coming on at all. 

It can either short or go open. Many were bad either out of the box or very shortly thereafter. I was working closely with two people (who I consider experts) who really got into this loco electrically when it first came out. 

Regards, Greg


----------



## StanleyAmes (Jan 3, 2008)

davey


I have some experience with the Bachmann K27 as I now have 4 running on the railroad. I also provided some suggestions to Bachmann during its development.


I made a short video last year showing the performance of a K27 in operation
http://www.youtube.com/watch?v=s-0iUbSXl2s

In a normal operating session we have a train with a mid train K27 helper which is fun to operate. Still training my operators on whistle signals

I tend to use Phoenix P5 sound boards but there are several other good ones in the market.

On the K27 the chuff is chuff high and many of the common sound boards in the market require a chuff low. A simple inversion transistor is all you need to convert from high to low.

The Bachmann site has many of the common installations in their documentation section. The QSI one is the simplest to read and can be used with any others that require the inversion transistor.

QSI makes a great decoder. However the stock parameters for back EMF on the QSI board do not provide good performance with the Pittmann motor in the K27. Hopefully Greg can publish a better performance set.

According to the reviews the best motor performance boards in the market are Zimo, Lenz, and ESU not far behind.

Greg

The sensors in the K27 are prototypically right on (although 180 degrees backward) I personally do not like synthetic chuff and prefer to be able to adjust the chuff in and out of square to make each locomotive sound unique as it should.

Since you have a K and have the QSI board try it.

Stan Ames


----------



## Greg Elmassian (Jan 3, 2008)

I do not have a K27 now, the K you have heard me refer to with the QSI and BEMF problems is an Accucraft/AML K4, which is now sporting a Zimo decoder. 

We have not had problems with the motor and a QSI in the K27 to my knowledge. 

Regards, Greg


----------



## East Broad Top (Dec 29, 2007)

No problem, Greg. The front light comes on and stays on with the small adapter board, which could stem from the diode being bad. (It's the only component on the board, so not a whole lot else to go wrong.) I'm using it instead to control the firebox and cab lights.  I'm still at a loss to explain why the directional lights work fine with the dummy plug, but not the Revolution board, which leads me to think it's a Revolution issue. Whether it's a weirdness in that specific decoder, I don't know. I wasn't in the mood to pull my other one out of the mogul to check. Since it works as I want it to at this point, I'm curious just for being curious. 

Back to the QSI board... 

Is there an on-line manual which will show the CVs and how to program them? I looked on QSI's web site, but the only references I could find were in connection with using their PC software to do the programming, which I don't have here. (Nor do I have the hardcopy QSI manual for the 2-8-0 install I did anymore. Bummer, that.) The K-27 that's got the QSI board installed has a few parameters I'd like to change. The headlights are backwards (i.e., it thinks the tender light is the front), and I want to reset the auto-chuff to match the rotation of the wheels. 

Later, 

K


----------



## Greg Elmassian (Jan 3, 2008)

Kevin, the reason why the directional lights work with the dummy and not with the Revo is probably because the Revo is not giving the same absolute voltage changes. The pins for the front light and the rear light do NOT go to the lights directly, but to a transistor "switch". This is undoubtedly the reason. 

Bachmann could call it a Revolution issue, but Aristo might say that the transistor does not exactly emulate a light. 

Since there are no real specifications for voltage levels for lights on and off, you are kind of stuck with a "defacto" standard. 

Bypassing the transistors, and using proper dropping resistors would be one way to do it... ahhh.. and you did ;-) 

No online manual, the complete manual for a QSI is very large, due to the many things you can do and the fact it is a motor decoder and a sound decoder. 

Download the HO manual from the QSI site. 

I do have a few "tips" on the chuff and other things on my site, under the DCC section. 

*http://www.elmassian.com/trains-mai...mming-tips* 


Regards, Greg


----------



## daveyb (Feb 28, 2009)

thanks everyone,,, 

it looks like im going for the lens gold maxi and the p5 sound board,,,, 

and gut the socket etc 

who stocks the bemf ,, im not sure on this ,,, how does it work and is it easy to fit,,,, 

the diagrams are great by the way,,, that bob grosh is a talented man!! respect is due 

thanks for the help 

davey b


----------



## jimtyp (Jan 2, 2008)

Back EMF is built into the motor decoder (in your case the lens gold maxi). I don't know that specific decoder but Back EMF will probably be enabled by default and the manual that comes with the decoder will provide the CVs and values to tweak it if needed. Someone that uses that specific decoder with the K-27 may be able to provide info if they modified any of the CVs that affect the Back EMF.


----------



## TonyWalsham (Jan 2, 2008)

I know this isa DCC related thread and I am not commenting on DCC per se. 

However, the Bachmann lights work perfectly when grounded via an open collector transistor such as the BC337 type I use on my PnP ESc's. You plug the ESC's in and everything in the K-27 works exactly as it should. I have the same transistor bult in to invert the chuff signal and it works "perfectly" with the chuff trigger on the P5.


----------



## steam5 (Jun 22, 2008)

Davey I get my decoders from 





http://www.dccroundhouse.com/





Good service, highly recommend.





When I first installed the gold maxi in my K-27 I needed to play around with one of the CVs which adjust the motor control. I did this because the motor was a bit erratic under default settings. I can’t remember exactly what number I changed to get the best performance, but if you have troubles post them on MLS and I or someone will help





Alan


----------



## daveyb (Feb 28, 2009)

cheers alan,,, as usual ive had loads of good advice,,, 

thanks everyone !! 

db


----------

