I'm getting ready to install my NCE system and after reading through the manual I have some questions: 1 - I have a 10" long green/yellow wire and can't find anywhere in the manual what it is used for. 2 - A separate (loose) page in the manual describes building a "diode bridge" to reduce the voltage from a transformer by about 1 volt. This is apparantly, to protect the PB105 from damage. What is a diode bridge and how do I build it? 3 - On the other side of this same loose page there is reference to adding 1 or 2 12v 100mA lamps (Radio Shack #272-1097) between the Powerhouse Pro and the programming track. What is this all about and where should I mount them? Do I need to see them? 4 - I'm planning on buying a transformer from TTX (Tony's Trains) as they are mentioned in the owners manual. Is this a good transformer to buy or is there a better one somewhere else? Any problems with this one? Thanks, Michael
I'll try to help -- but, I too have no clue as to that wire (mine didn't come with one....) The diode bridge is used to lower voltage, each diode drops around .7 Volts with no other effect on the signal (other than only allowing voltage of one polarity through) Since DCC is an AC signal, you must be careful to install the diodes in such a way that you still get AC on the output. This means that you must have pairs of diodes in both directions (direction on a diode is marked by the band on one end - that is the "minus" end (positive charges flow from the other end to that end). So, for a 1 volt drop you'll need 4 diodes -- two in series with the bands on the same end and the other two in parallel to the first ones, but with the bands on the opposite end. The two diodes will give you a drop of around 1.2 Volts. However, I don't know why you need to do this as the output voltage is adjustable (inside the booster, see the manual). The lamps are a cheap short circuit protection -- if there is a short, the lamp will light rather than the output transistors. The low current that the decoders normally use will pass thru the bulbs with little effect (not enough current to light the bulbs). If there is a short, the extra current will go to light the lamp filament rather than frying the output stage. Being able to see the lamp or the light from it, will tell you there's a short. The lamp needs to be in series with the programming track (ie. current goes thru the lamp on the way to the track). Of course if you're careful and never miswire a decoder you won't need the lamp. And finally, the TTX transformer is fine -- I've been using one for a year with no problems. When I got mine, I had to build a box to house it (it did come wired, with all the necessary circuit breakers) -- I think it now comes in a box which is a great boon. If not, you may want to consider Loys Toys, they sell one in a box. And, even tho' you didn't ask, consider the "fast" circuit breaker sold by Tony's as well. This shuts off the track power when there is a short, before 5 AMPS thru the shorting wheel welds it to the track (it's worth the $26 just to not have the pits in the rails from past shorts) And finally, check www.wiringfordcc.com for LOTS of information about DCC!!
I just thought what the wire is probably for -- the connection between the command module and the booster (ie. the right side of the control unit and the left side). The right side generates the command pulses and the left side amplifies them to the track, but they are not internally connected (makes it easier to expand). Good luck and have fun with your NCE.
Yep, that pretty much sums it up, and I agree with you on that wire. However I don't think the diode is necessary for the TTX transformer (which we have). Nor are the lamps required, but they will certainly help, and are worth the couple of bucks you'll pay for them. Enjoy your system, it has a lot of options and features that I have really enjoyed. ------------------ Corey Lynch Pres - Rensselaer Model RR Society, NEB&W RR http://www.rpi.edu/~lynchc/Railfanning/railfanning.htm - My Site http://www.union.rpi.edu/railroad/ - NEB&W
