Tony, I'm running about 21 - 22v. There was an article in Model Railroad News that stated the Scale mph was 31 at 22v at full throttle on flat track. I have not verified this. There is a blurb on the Blackstone site that says the K-27 could get up to 45mph (based on what old-timers stated: reference
). My understanding is they typically ran at 20 - 25 mph, which according to the article in MRN would be about 50% of full throttle at 22v (23 scale mph). I prefer to run models similar to prototype speeds, but if I try and run at this speed the chuff cuts out, it starts cutting out about 40% of full throttle at 22v.
If i could get the chuff to not cut out at even 50% of full throttle at 22v I would be happy with that speed
I can always go back to magnets but I'd still like to get the optical chuff working if possible, but I'm getting close to giving up on it. I see where others have had this same problem so I don't think my K-27 or P5 are defective.
My power supply is switchable and if I run 16v I can't get near what my locos run at 22v. So I'm sure those running at 14.4v would not see the problem even at full throttle.
I have the P5 connected using an NPN transistor, as that is what Pheonix says to use. Some say it is not needed, but when I called Phoenix (John) they said it is required for the P5 but not the 2K2. So I have not tried the install without one. Phoenix said they would send me a 2K2 to test to see if I have the same issue with that card, but I'm still waiting after 2 weeks.
I also tried a 0.1 capacitor. It helped very minimally in my case. Another theory is that since I run DCC that mabye it has some extra noise that battery or DC folks do not see?
I think you have done a great job with the RCS system, and as others have noted, I believe yours is the only true Plug-n-Play install for the K-27. Well done!