I decided to go with parallel wiring for the LEDs, so I wired in a bridge rectifier. I got these for really cheap a while back, but they are larger than can typically fit into O-gauge items. However, they fit perfectly inside this recessed hallway:
I soldered the DC leads from the rectifier into the modular plug on one end of the light rack, effectively converting the two copper strips into a DC bus.
I had to disconnect the modular plug from the other side, since that would interfere with the DC signal. But this would mean losing the benefit of feeding from both pickup rollers. So I soldered two wires on top of the frame to connect them:
Then I set about soldering in 7 white LEDs. I thought about wiring them in series, and this would have saved me from having to solder in resistors for each LED. I believe it also would have been a more efficient use of current. But it also would have meant less protection for the LEDs in the event that they were accidentally fed more than 18-20 volts.
As such, these standard (and inexpensive) white LEDs produced the dreaded blue glow, further exaggerated by the blue upholstery:
So I started experimenting with the white LEDs. This photo shows some of the tests I did:
- To the far left is just a plain white LED with no paint on it. Quite blue.
- To the far right is a white LED with yellow paint on it, to counteract some of the blue and provide some "warmth". Quite yellow.
- The second from the left is probably the best for general purposes, as it appears nicely white. This was accomplished by painting it with a cheap acrylic paint that was just slightly off-white. Call it cream. Anyway, this still looked rather blue in the test Amfleet car, due to the blue interior colors.
- The middle one is painted with a mix of the cream-white, and orange. This was a bit too rich of an amber, and also I did not water it down enough, so the LED lost a lot of its light.
- The second one from the right is perfect. I mixed less of the orange with the cream-white, and watered it down further.
So I mixed up some more of this color, and proceeded to paint not only the LEDs themselves, but also the roof of the shell, so that even the reflected light would get an "amber boost".
More to come...