# Transistor for Bachmann K-27



## Mike Ballou (Jan 3, 2008)

Can anyone out there tell me what transistor number is to use in the chuff circuit on the Bachmann K-27's? I have a diagram of the circuit that I picked up at the Del Mar Train Show today here in San Diego but I forgot to get the transistor number so I can run over to radio shack to pick one up. 

Thanks,
Mike Ballou
Carmel Valley RR


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## Greg Elmassian (Jan 3, 2008)

Are you talking about the transistor to invert the "sense" of the chuff circuit? I think it was an NPN like a 2n3904, but I have not seen the circuit, and would be loath to recommend how to do it. I think you want the circuit that Stan used. As I understand it, he did not use a resistor to the base, nor a resistor on the emitter. Somewhat sketchy. 

Regards, Greg


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## Mike Ballou (Jan 3, 2008)

Greg, Yeah, Stan has already sent me the specs that I need to install that circuit. Thank you for your input. 

Take care and thnak again,
Mike Ballou


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## Greg Elmassian (Jan 3, 2008)

Any time Mike, you are in San Diego aren't you? I'll be at the show Sunday. 

Regards, Greg


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## Mike Ballou (Jan 3, 2008)

Hi Greg. Yep I'm still down here Penasquitos. I was at the show yesterday. Big crowd! I picked up a few of those new Jackson Sharp Rio Grand passenger cars and a whole lot of info about the new K-27 I got last week. I am installing AirWire and a Phoenix P5 board. Thats why I need the transistor. 
Have a good time at the show. Be sure to check out the layout in the second building. We will be at a Charger football party today. 

Mike Ballou


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## bobgrosh (Jan 2, 2008)

Posted By Mike Ballou on 01/12/2008 10:27 PM
Greg, Yeah, Stan has already sent me the specs that I need to install that circuit. Thank you for your input. 

Take care and thnak again,
Mike Ballou


I don't get it!

This is a public forum!
Questions are asked here not just for the benefit of the person asking, but so that we might all be informed!

If Stan sent you the information you needed, why did he do it back channel? Why didn't he just answer the question here for all too see?
Why is everything about the installations in the Kay so veiled in secrecy? I'm not criticizing Mike on this, just the general tone of all the posts on all the forums.

Installations have been done, but are somehow hidden away for publication at some future not yet determined date.
The only actual usable information is hidden away under "some new loco" 
You would think that Bachmann is the CIA.

What is going on here.
If you have the information about how to install the transistor, what part number, what resistor values, what solder pads to attach it too, then PLEASE SHARE IT!

Why all the mystery?


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## TonyWalsham (Jan 2, 2008)

I posted the following at the Bachmann forum.
I guess it should also appear here as it is relevant to the situation.

_"IMHO, asking a LS train consumer to go to an electronics store to obtain parts that they then have to install themselves, just to get something to work out of the box, is fraught with danger.
If Bachmann are not careful they will have a PR disaster on their hands in no time at all.
IMHO, although I still don't like the idea of the socket pcb and would much prefer simple screw terminals, I do concede that it is here to stay.  Apart from the chuff timer, I do believe Bachmann have got the actual PnP socket pretty right.

It is the aim of RCS to recommend battery R/C installations that do *NOT* require any modifications or additions to the existing Bachmann wiring whatsoever.
This may or may not happen.  
Please be advised.  Only when RCS can get hold of a K-27 to actually install an RCS battery R/C system, will RCS announce the RCS authorised installation procedure(s).
We want to get it right and not go off half cocked recommending "fixes" to the Bachmann wiring when it may not be necessary to do so."_


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## Mike Ballou (Jan 3, 2008)

Bob, 

If your send me your e-mail address I will send you a copy of the documentation that Stan sent to me. I do not know how to attach a document to the forum, otherwise I would just place this there. It is not a deep dark secret that I know of. I learned about this circuit over the weekend at the train show here in San Diego but I failed to get the number of the transistor to install. That was the purpose of my inquirey. Stan was nice enough to send it to me and I will pass it on to you. If you know how to attach it to the forum then by all means feel free. I am new to these forums and do not yet know all the protocols involved. 

Regards, 
Mike Ballou 
"Trainman" 
San Diego


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## Greg Elmassian (Jan 3, 2008)

Bob, 2n2222 or equivalent... connect base to bachmann chuff pin, emitter to ground, and use collector to go to your sound board. If you sound board does not have a pullup resistor, add one to the sound board input, 22k to plus voltage should be fine. Be sure to connect the ground on the bachmann board to the ground on your sound board. 

Regards, Greg


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## Mike Ballou (Jan 3, 2008)

I thought I would update the forums on this chuff transistor circuit. I was informed of this transistor circuit last weekend at the Del Mar Train Show. Stan Ames sent me the transistor ID and information on how to install it. 
The circuit is now up and running in my K-27. It is powered by an AirWire controller fed from two lithium-ion batteries, wired parallel, located in a trail behind battery car. The sound card is a Pheonix P5. Both came from Jonathan at Electric Model Works. 
The chuff circuit is performing perfectly. I am getting the exact sounds from the sound card that I programmed it to emit. It is using the chuff circuit as it's que. Now this K-27 looks and sounds just like the real Mc Coy. 
I do not know,as yet, how to post either pictures or attachments to these forums, but if anyone would like to know any information on this circuit, how it installs or how it works, just send me an e-mail and I will be happy to help. I will be gone till next week on a clampper outing but will be returning in time to watch the Chargers and New England play, yipe! 
As stated above this circuit came from Stan Ames. If this did not work the magnets on the axle were plan "B". 

That's it, everybody out there take care, 
"Trainman"


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## Greg Elmassian (Jan 3, 2008)

Please send it to me, I'm documenting a few things on my site, and want to be sure I've got it right.

Thanks, Greg
[email protected]


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