I have a factory painted Mantua P.R.R. 4-4-2 that I purchased in the 1990s which I have been running on DC. Now I am replacing the headlight with an LED and have decided to install DCC also. The unit has a factory installed Seuthe smoke unit and both the headlight and the smoke unit share the same 12V leads (in DC) jumpered together in the smoke unit.
I don't yet know if the motor (looks like a can motor) is isolated..probably isn't. Does anyone know? The engine runs well enough at speed but does have a high starting speed.
I am thinking I need to separate the Seuthe unit from the headlight if I go DCC. The Seuthe unit probably draws 130ma at 12 volts which will probably burn out the decoder if I hook it up to the same outputs as the LED.
Any advice/counsel would be appreciated.
George T. Galyon/Olde Newburgh Model RR Club/Walden, NY
If it's the newer one with the can motor it shoule be ok. Test the motor draw without the smoke generator connected, stalled, just to make sure it won;t exceed a typical decoder drive output. If it's really a can motor it ought to be isolated, or easily fixed - remember it's the BRUSHES that need to be isolated from the track pickups, not the motor chassis itself.
Definitely right about the smoke generator. You need either a small relat (with a diode across the coil) or a solid state relay to drive it off a decoder function output. You may also want to check out the specs onthe smoke generator - way back when, Seuthe sold two kinds, one was meant to be used with the constant 16-18VAC off the accessory terminals of a power pack, and the other was meant to be used with the variable track voltage to put in a loco - they heat up on lower voltage so you don;t have to run the train around at full throttle to get smoke. They will probably overheat with always on max voltage DCC, you'd need the other type for DCC. Or maybe they aren;t like that any more, this was nearly 40 years ago.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
My Mantua steamers had only one Motor wire going to the chassis. The other motor wire was connected to the tender pickups. The tender only picked up from one side on both trucks. The loco drivers, the opposite rail. If you are good, you can make pickups on the fireman's side of the loco. DCC needs all the pickups you can provide.
My locos were pre DCC, though.
I would double up the tender pickups for DCC.
http://www.55n3.org/cars/tender_wipers/
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Thanks for the response. I don't have the Seuthe specs. in my documentation but it must be the older, low voltage one designed to run on DC as this engine was bought way before DCC was around (as we know it today). I think I will just isolate the Seuthe unit. I can't see how to get it out of there as it is too tall to just drop down into the boiler.
Thanks for your note. I plan to use a TCS Keep Alive decoder which (hopefully) will obviate the need to use multiple pickups.
If you take the boiler shell off, the smoke unit will either be attached to the bottom of the stack or on the front of the chassis. You'll probably need to open it up the boiler shell anyway to get to the wires from the pickup and motor.
Spend some time in the SoundTraxx website. Lots of good info.
http://www.soundtraxx.com/manuals/Tech_note%2014.pdf