PRR Q-2 4-4-6-4 decoder install.
Since this is one of the more complicated installs due to all the LED's being used, below is a detailed description of the install.
I think this engine sets the record for LED's that I've ever installed:
Engine:
headlight: 1
marker lights: 2
running board lights: 4
cab light: 1
fire box glow: 1
Tender:
Headlights: 2
marker lights: 2
doghouse light: 1
Total: 14
Someone commented that the marker lights are too bright so I've installed a 6K resistor in series with the existing resistor that comes with each LED that I use.
Before:
After:
The resistors were obtained from digikey. Each LED comes with a resistor but all but one is needed when multiple lights of the same color are being used, ie: marker lights: both green LED red wires connected to one resistor. Each color LED has a different resistor size so the original needs to be kept as this reduces the 12-15 volts down to 3 volts (or so) to light the LED's without burning them out.
The new resistor is on the right and connects to the red wire on the LED side and the blue wire on the decoder side.
My preferred method of making connectors. As one can see, an 8 pin connector is less than a 1/2" in width. Of course, if you don't plan on lighting up your engines like a Christmas tree but only want the basics, a connector with a lot fewer pins will suffice. Also, if you don't want to control all the lights with function keys but still want lots of LEDs, again, one doesn't need 8 pin connectors.
My wiring schematic to route all wires from the decoder to engine and tender along with what function key controls that LED/S.
Decoderpro used to change address and checks that no wiring mistakes are made.
Long address used.
After info saved to decoder and decoderpro, it lists the engine and pertinent data. In this case the PRR Q-2 is 7th from the bottom.
Next, I connect the engine, via alligator clips, to the mainline and make sure sound and all light functions are working and of course, forward is actually forward: in this case I had to reverse the wires.
There are many excellent speakers on the marker but I'm partial to PFM's speakers. They were made 30-40 years ago but I have a sufficient supply to get a lot of engines completed. PFM speakers have excellent base qualities, which I want for my steam engines. PFM speakers require a few more electronics that the 'normal' speaker: ie two capacitors and a choke.
One rat's nest but, fortunately, the electrons always know where to go!
Tender lights working properly.
The doghouse light is connected to the same wire as the cab light. A 6K resistor was also added for the tender marker lights.
After the decoder has been tested for motor and tender lights, next step is to route all the engine LED wires and make a connector from boiler to frame. Tape is used to hold wires 'in place' while glue dries. It's important to check that there are no shorts to the boiler frame and LED wires via a voltmeter. Failure to do this will result in 'blowing' an LED, which means a lot of extra work removing the old LED and installing a new one.
Engine headlight. Canopy glue is used to secure the LED to the light housing but white glue is used to secure all wires going through other holes in boiler and tender.
