Here is a link to install the NPN transistor to use the optical chuff.

http://www.mylargescale.com/Community/Forums/tabid/56/forumid/17/postid/6266/view/topic/Default.aspx

I've also tried a 2N2222A NPN and it worked about the same, if anything not quite as well as the Radio Shack one listed in the link above.  Adding a 0.1 capacitor helped marginally.

I tried the DCC mode of the P5, but the K-27 is geared so high that even the slightest change in grade makes the chuff look strange.  The P5 DCC chuff mode works off of the start voltage and then reads the speed step packets off of the rail.  That is, the loco may be moving, slightly down hill with no chuff, or the chuff going and the loco is not moving slightly uphill.  Add rolling stock and it's even worse. 

I have the P5 working with optical chuff, using the NPN transistor.  Some say you don't need the NPN but I haven't tried it yet.  It works great at low speeds but at about 40% of full throttle (22v) it starts cutting out and by  60% it doesn't work at all.   My understanding is that the trigger (optical chuff) is so short the sound card sees it as noise and filters it out. 

So it depends on how fast you run.  I haven't done any scale mph testing, but I read a review of someone that did (Model Railroad News - does all scales).  Nice review of the Bachmann K-27 and good info on the real K-27.  Anyway, they claim at 22v and full out the K-27 was doing 31 scale mph.  I've heard they typically ran about 20-25 mph, which was about 50% of full throttle.  And the Blackstone site claims the old timers said they could get up to 45 mph on the straight aways and when no one was looking.

I like the look of the K-27 running about 50 - 60% of full throttle (22v), but the chuff doesn't work at that speed so I'm to the point where I'm going to go back to the magnets.

I don't know if the 2K2 works any better.  I'd be curious if it does then I'd swap the P5 for the 2K2.

First of all, always go with the wife, makes the hobby (and other things) better for both

Second, I agree with the wife because the bigger cars make the locos look small.  I'd rather have the cars look too small than the locos.

People are a different thing.  You can find 4ft people and 8ft people in any scale    So someone that is 6' in 1:24 is only 5' in 1:20.   Most 1:20 scale items represent the time period of late 1800's or early to mid 1900's, people were not as tall back then.

BTW, nice layout and nice pics.  What do you use to photograph?  Any tricks you can pass along?

Greg, thanks for you input.   

Yes, the capacitor was to reduce noise, and it did help but only fractionally.

This is the first I've heard that the NPN transistor is not needed.  I'll give it a try.

Yes, if Phoenix can't come up with a solution that works with the optical chuff in the next few weeks I'm going to just go back to using magnets.

You are getting better service over there then than I am over here.  I sent in my FAX of my proof of purchase and have not been notified of anything.

If I don't hear back from Bachmann in another week I'll try asking Bachmann of UK for the counterweights 

Phil, which smoke unit are you referring to?  I was assuming the SD-45 unit with a fan?  The instructions that came with mine says it can take up to 24v direct.  So I did and mine works great.  I run DCC and have a constant 22v to the track, no problem.

Anyone have luck putting in a Phoenix P5 sound decoder using the optical chuff?  Mine works but only up to about 40% of full throttle.  Then it gets erratic and finally cuts out.  Phoenix had me try some capacitors but they only helped slighlty.

Does any sound system work all the way up to full throttle using the optical chuff as the trigger?

I had a problem with mine.  I run track power and when my loco went over a dead spot the smoke unit stopped.  So I modified the smoke power pickup to come from the loco and the tender.  Yes, had to run an additional pair of wires, but since then it works all the time. 

Also, if you have DCC, I set up an output from the decoder to turn the power off to the smoke unit with a click of a button.  So if it did turn off I could easily turn it back on.  Recycling the power to the unit was the only way I could find to turn it back on.

Steve,

I have a K-27 and am very happy with it. 

Yes, I got a DVD with mine.  It showed the model running and how to lubricate it.  There was also a small manual that had the lubricating info and some brief history on the K-27.

If yours came with a decoder then it was probably the reseller that forgot to add these items back in, as Bachmann doesn't sell the loco with a decoder.

I've also heard the fan when idling.

In case you haven't heard the counterweights should be replaced.  Here is a link explaining the details:
http://www.bachmanntrains.com/home-usa/board/index.php/topic,4303.0.html



-Jim

This is the best K-27 case I've seen:

http://www.mylargescale.com/Community/Forums/tabid/56/forumid/8/tpage/1/view/topic/postid/7916/Default.aspx#7916

I also find the sockets very difficult to unplug.  I snipped off the tab locks, and that helped.  I also found if you don't push the plugs in all the way they are a little easier to pull back out.  Even with these two I still find it a bit difficult to pull the plug back out so I end up using a pair of needle nose pliers to pull them out.  I'm thinking of adding some sort of pull tab but haven't figured out how to put something on that won't break off or get in the way.

As far as how to handle the loco I too have the same question.  Currently I hold it at one end under the cab roof, as you do.  The other I grab under the smokebox but it's not the easiest as there is not much room and a little tight for my short fat fingers, but it's the best I've come up with.

I saw where someone developed a really nice carrying case and just left the tender attached all the time.

Gorgeous Matt!  Great work by Dave!  One item, I see the number on the side of the headlight looks like 455 instead of 45?

Rick, are you installing a Phoenix 2K2 or P5?

Even after the transistor there is still a problem with these at higher speeds.  At about 40% of full throttle the chuff starts getting erratic and at about 60% of full throttle the chuff cuts out completely. 

The fix for the 2K2 is supposed to be simple (I only have a P5 so this is just what I've heard).  if you have the programming interface, you can go to the Terminals icon and uncheck the box next to the P1 Trigger.  This is supposed to be the fix.

For the P5 the fix is not as simple, and I still don't have a perfect fix. Phoenix is working on it but they don't have it yet.  It turns out noise is causing the chuff to fail at higher speeds.  They suggested I put a 0.1 capacitor on the transistor leads that go to J1:5 and J1:7.  This definitely helped but didn't fix it 100% for me.

Is this what you were looking for?

http://www.bachmanntrains.com/home-usa/board/index.php/topic,4021.0.html

Also check out:
http://www.trains.com/TRC/CS/forums/1323139/ShowPost.aspx