I replaced an incandescent headlight bulb from my RDC-1 and tested it with a 3V 30mA 3mm LED and a 12V 30mA LED and none of the LED's lit up. What went wrong any help would be so much appreciated.
Please read the wiki article on how LEDs work. You can't just unplug a light bulb and put an LED in place, it won't work. The Proto headlights are wired for constant directional lighting and place low voltage light bulbs across diodes to get the proper voltage to the light bulbs. This isn;t enough for an LED. ANd LEDs require using a resistor to limit the current. LEDs are nothing like an incandescent bulb other than they both give off light. Incandescent bulbs draw a certain amount of current based on their design. Period. A 30ma light bulb draws 30ma. The current rating on an LED is a MAXIMUM do not exceed number, it is NOT how much the LED draws. The VOLTAGE rating on an incandescent bulb is a MAXIMUM do not exceed number, the voltage on an LED is how much voltage it uses, period.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I understand where youre comming from but I still don't understand how those darm Proto 1000's circuitry are wired. Remember I also tested a 12V pre wired LED. Thats an LED with a resistor already added to it.
Most Proto light boards are 3 diodes in series, witht he light bulb across two of them, givien it 1.2 volts. The third diode is for directional control. Duplicate the same thing with 2 more diodes but facing the opposite way and that takes care of the rear light. The two sets of diode circuits are anti-parallel to each other, and that whole setup of 6 diodes is in series with the motos. This drops the voltage to the motor, so that as you turn up the DC power, the lights can come on before the motor gets enough volts to turn. Since the bulb is wired across the diodes, the voltage is constant regardless of the track voltage.
Clear as mud? Now the simple fix fo installing DCC decoders - rip all that junk out. None of it is needed for DCC. Ever. Red and black wires fromt eh decoder go to the right and left rail pickups. Orange and grey go to the motor leads. White and blue for the front light, yellow and blue for the rear light. No silly circuit to get in the way.
The 12V LED can be conencted right to the decoder. The BLUE wire is the positive terminal ont he decoder. If it doesn;t work, flip the LED around. A "3 volt" LED needs a resistor. For the kind you usually get for trains, a 1K resistor is good. AGain the LED is polarized, so if it doesn't work it may simply be backwards. The small surface mount LEDs can be insanely bright, they may need more than a 1K resistor to look decent, but a 1K will limit the current to a safe level.
No regualr LED or 12V LED will work as direct replacement for the bulbs in a P2K loco. Unless you are using a G scale power pack that goes up to 18+ volts, you cna probably get away with hookign a 12V LED right across the track. It will only light up in one direction. For DC power and a regualr white LED, you'll need a reistor of about 470-560 ohms. Again the LED will only light up in one direction, and only after the track voltage gets above the LED's voltage. This is for DC only. For DCC you use the 1K reistor and hook the LED to the function wires liek I said above.
Alloboard,
I just purchased 2 of these Proto 1000 RDC's and converted them to DCC. In doing so, I also changed out the weak lights for 3mm Golden White LEDS. The circut boards that came from the factory have MAJOR issues and are NOT DCC friendly or lighting friendly. If you are doing a DCC install, contact me off list and I'll be happy to send you some detailed digital pictures of my install.
Mike