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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.
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.
