I posted this on the Bachmann forum and thought it would be useful if I posted it on LSC as well.
The K-27 was the first Bachmann large scale locomotive with the plug and play socket. The chuff circuit in this locomotive was designed with a chuff that goes positive to indicate a chuff. While some sound boards work fine with this design, most prefer a chuff circuit that goes to ground to indicate a chuff. This required the end user to install a transister and often a capasitor in the tender to allow the chuff to work properly. All Bachmann locomotives with the socket since then have a chuff to ground circuit.
My wife and I have a large outdoor railroad with several Bachmann K-27 and together with some of our operating crew designed a replacement PCB-5 chuff circuit board that incorporates both protection circuits as well as a chuff to ground design. For a limited time we will be offering these replacement boards for $30 each plus actuall discounted shipping. Note: We do not intend to produce these as a product going forward, this is a one time offering.
This circuit board is a direct replacement for the origional PCB-5 circuit board that sits right behind the motor in the K27.
In the above photo, the board on right is the origional Bachmann PCB-5 circuit board. The board on the left is the newly designed K-27 PCB-5 circuit board.
If you are interested please send me a note.
Stan