Well folks, after being out of the hobby for 15 years, I’m diving in head first! I picked up 3 DCC ready Bachmann ALCo S4’s and I’m using MRC decoders and speakers. I’m no stranger to soldering small electronics, but these mini LEDs are new to me. I’m Wiring an LED beacon to one of my KTRy units, it’s a “big al Mayo” beacon, are the colors on the mini LED wires a thin insulation coating, or do I need to separate the wires? Does it matter what side I put the resistor on? What’s the best place on the loco to solder the common (negative)? Also, when adding DCC/sound to these Bachmann switchers, any advice on squeezing it all in the shell, and speaker placement? Thanks!
Here is a photo of what I'm working with:
The LED wires are insulated. They may just be enameled magnet wire, which can be stripped simply b heating with a soldering iron.
Does not matter which leg of the LED th resistor is in. Kepe them all the same for consistency though.
The common in DCC in POSIIVE, it's the blue wire in the decoder. Should be a place for that on the factory board as well.
Sound is probably not the palce to start if you've never ever installed a decoder before. But search around, there are photos of installs for nearly any loco out there. Even if the example uses a different brand of decoder, the concept is the same. For a loco with a tight space, a board repalcement decoder is usually better than one that plugs in like that, the plug and wire harness ake up valuable space. Speaker (with enclosure - you NEED an enclosure for the speaker as well) usually ends up in the cab on a small loco. Sugar cube speakers, or perhaps iphone 4 speakers, give the best sound in the smallest space.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
If you go to the Bachmann site you will see in the Bachmann Parts page for the S4 where the speaker and baffle go. Click on the pictures and they will enlarge. They sell it. I just looked. You need a baffle.
A nice diagram of the sound model and sound board.
Sugar cube and iPhone speakers are very good also.
On the PC board cut off C1 and C2. What looks like two green resistors are Ferrite inductors. Labeled L1 and L2. No resistance. I have measured them with an inductance meter many years ago. 4.7uH inductors . The color codes are online.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
You may have to remove part of the shell inside the cab to get the decoder to fit.
I would look at this speaker from Bachman:https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=68_573&products_id=7121&zenid=7i36ee1ej90gh5c635m5v9t4b5 You'll need for screws to mount it. Part number 10597.
You couls also remove the pc board and hard wire the decoder. The green wire on the MRC decoder should be for wireing your beacon. It should explain this in the instructions. Joe
Thanks for all the replies guys! It looks like I’m going to have to remove a section of hood plastic that extends into the cab to get the speaker to fit. Also thanks for the wiring advice, I’ll update with the final results!