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Discussion Starter · #1 ·
By now it is common knowledge that the Bachmann K-27 chuff timer does not work with the majority of the after market sound system available to LS'ers, unless modifications are made to the Bachmann wiring.

There are two basic problems with the design.
1).  The chuff trigger output  is back to front.
2).  The chuff trigger does not work at low speeds on regular DC.

1). Has been caused by the chuff timer emitting a positive voltage output which, according to Mr Stan Ames, only one sound system on the market (ESU) can read.  
All the more popular sound systems on the market such as Sierra, Phoenix and Dallee all want to send the voltage output trigger to ground via the chuff timer.  
Although the fix is quite simple for someone with a basic knowledge of soldering etc, Bachmann will be making a rod for their own back if they recommend just such a "procedure".  Still that is not my problem and not the point of this posting.

2). Is just inherent in the design.  The chuff timers are opto - electronic and (again according to Mr Ames) require at least some voltage on the track to make them work.  
Getting them to work at low speed will require a battery supply added to the basic K-27 wiring.  In fact Mr Ames has suggested using the Sierra back up battery for just such a task.  Plus Phoenix have just issued a circuit for a way of doing it as well.  Phoenix caution against the operator using the smoke unit as doing so will rapidly run the Phoenix battery down.  No doubt the Sierra battery will suffer the same result with the smoke unit working.
Again that is not my problem and again not the point of this posting.

All of the above could have been easily avoided IF the chuff timer had been mechanical and not use opto - electronics.
Mr Ames has been forthright in his support of both the optical electronic chuff and the + output of the chuff timer itself.

Recently Mr Ames answered by direct E mail to me a number of questions I had posted at the GR forum.  Part of the answer to one question contained this gem.

The chuff works just fine as per the proposed specifications. I personally believe that having discussed this at great length a consensus is beginning to be formed that a ground chuff may be what the industry desires. Before this can be done, protection of the internal locomotive electronics must be considered.

To me that looks like an admission that the chuff design is wrong.  
Period.
However, it will not just be enough to change the polarity of the trigger voltage.  
Why not make the polarity selectable by the user?  That would be easy enough to do and would not change the wiring too much.

Stanley, for once don't just consider what the industry wants.  Consider what the consumer wants.

The real problem is that simply changing the polarity does not solve the no chuff at low speed.
That can only be fixed properly by changing from an opto - electronic method to a mechanical method.  Either wiper contacts or a reed switch and magnets.
Dave Goodosn has come up with a quite simple way of doing it.  
I think the same result could be quite readily achieved with reed switches and magnets in the cylinders.
As mechanical chuff timing can read high or low, very minimum changes to the wiring need be made.   Although having only one circuit at the dummy plug when it should be two connections complicates the situation and will mean selecting whether the mechanical timing should read hig or low.

A mechanical chuff timer will start chuffing as soon as the wheels start turning no matter what the voltage is.

I urge Bachmann to consider all options before jumping in and modifying the design.
 

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Discussion Starter · #3 ·
Del, 

Dontcha just love the bit where Mr Ames says:

The chuff works just fine as per the proposed specifications.

Well I guess it does.
Obviously someone (nudge nudge, wink wink) got the specifications wrong./DesktopModules/NTForums/themes/mls/emoticons/crying.gif
 

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Tony maybe they just figured everyone will run them at full blast anyway so who needs good slow speed characteristics...

The client likes it, guess thats all that matters, who gives a fig about who's actually going to use it?

I have my answer to a question posed a while ago about this model, the answer is "much nashing of teeth", namely a certain block of consumers...
 

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That's probably why there is a 2-chuff per rotation option.
So you can "hear them chuffs" at warp factors, eh?
 

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I'm going to expand on what Tony said a bit.  A rant, in B flat minor:

Apparently the "industry" has a "need" to advance the technology involved in our newer locomotives without regard for whether it actually improves performance, or enhances people's model railroad experience.

I want a locomotive that does what I want it to.  That is, it should move in both directions, have appropriate sound effects, and be something I can control without re-inventing the wheel on how my layout is built and wired.  The model should be as accurate and finely detailed as possible, and have a price that I can afford without sending the family finances into a panic.  And the choice of prototype should be something that appeals to me.  A manufacturer who can do that is being sensitive to MY needs.

The last two locomotives from one such "industry" representative have included enough things that do NOT appeal to me that I skipped the last one, and while I couldn't resist the model itself on the most recent one, the magnitude of the surgery I'm going to have to do to make it useable with the rest of my railroad has reduced the number of them that I planned to own from two to one.    

That's a total of about $1150.00 that I did NOT spend on that company's products in the last two years.  You' d think that would grab someone's attention someplace. Unfortunately, though, when I mention this kind of thing, I'm told that I'm a dinosaur, that I'm insensitive to the manufacturer's needs ... and that the problems I'm encountering don't exist.  On the other hand, that perception could be a result of my confusing the remarks of an insider who's not actually a company representative but behaves like one (remember "Mr. Wendy's, Unofficially?") and who's speaking out of school with an official sounding statement with someone who actually is making an official statement at the company's behest.  Either way, it's not an approach I've ever heard suggested as a good one for dealing with customers.

These folks need to stop worrying about our sensitivity, and start worrying about our satisfaction.  They also need to start asking themselves who's leading them in their current direction, and whether causing the kind of ill will it's generating is being particularly sensitive to their own needs.

Matthew (OV)
 

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Discussion Starter · #7 ·
Just so folks know.

A written proposal outlining how Bachmann could very simply solve the chuff problem has been sent to Bachmann.

It will be interesting to see if this is "leaked" as an idea by someone on how to fix the problem just like the loose counterweight "procedure" has been.
 

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As a "johnny come lately" to 1:20.3 scale, I'm sure someone has mentioned before how much money hobbyists have spent on a little switch in the smokebox to decide which way you want your locomotives to be wired. Even if it only adds $5 to the loco (probably more than that!) it's too much. All I want is two wires from the track to the motor. Leave out the cheapy smoke generators, the wrong colored marker lights, the incompatable chuff switch, the extra wiring for I don't even know what, I guess I can live with a headlight, but seriously, there are more than enough aftermarket providers to make anything we could possibly want to add to our locos. Feel free to knock $100 off the price so we can spend that $100 buying what we really want. If Joe wants Airwire and Phoenix Sound, and Bob wants DCC and no sound, or Chuck wants trackpower and a tape recorder, everyone can have what they want!

Perhaps, just perhaps, the "industry" should be just a tad more "consumer driven" than it is becoming...

My two cents: Robert
 

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Hi Folks
About twenty of my hundred locos are Phoenix steam powered sound systems all magnet controlled either driver or tender wheels.
Most of the rest have various sound systems

These are the main display locos so need sound from very low speeds anyway most dont go above 15 MPH .

I wanted a K27 but will not add one to my system due to this mess.A simple socket is fine and a contact on the drive axle for sound but not half the tender filled with useless electronics as all I use is DC.

Another snag on my four Connies I have rebuilt the tenders lowered to a better level and used up most of the coal ie fitted the side tanks and coal slope.

So the useless electronic would have to be scrapped Ugh

Why have locos that nobody has ever used any fuel all are full!
Dave
 
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