DCC Conversion Question: Loco light bulb

Model Railroader Layouts and layout building
1

When I ordered a decoder from Tony’s Trains I asked for a replacement light bulb. He said that the bulb was difficult to get to, and it was easier to wire a 240 ohm resistor in line with the bulb.

When I ordered decoders for my daughter’s Proto 2000 F2 A/B units I forgot to ask about light bulbs and therefore I didn’t get one. The first thing the directions say is to replace the bulb.

The questions are:

What happens if I don’t change the bulb?

Can I assume that if there were a blue lead and a white lead coming from the bulb I could do like Tony’s suggested: solder a 240 ohm resistor along the white wire and solve the problem that way?

(I’m going to try to find a 12V bulb first but my LHS has about one chance in a hay stack of having one.)

2

DO NOT even attempt to run without changing the bulb OR putting in a resistor. The light bulb will instantly blow out, and will generally kill the function output on the decoder at the same time.
My choice for units that need bulb replacement anyway is to use an LED. Golden White LEDs have a nice yellowigh glow to them that looks right for early diesels and steam locos with incadescent lights. Use a 1K resistor witht he LED and you’re all set.

–Randy