Yes, DCC decoders send PWM (Pulse Width Modulation) to the motor with DC control or DCC control.
Also, some DC controllers will not operate some decoders if the controller is not pure DC. You have to turn off the pulse power option on the controller.
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.
I know but I just installed another Tsunami and thought i would look at that one with an 'Oscope. I like Reader's Digest also. We all get old.
It also keeps the critics busy.
Cheers
I found out the Tsunami sends pulse power to the motor when operating on DC. I found that interesting. In case anyone wonders.
Using a 1k resistor would be ok, in fact many use the 1k.
I cannot post a video of the loco running as the motor power from the decoder failed. I have sent the decoder to SoundTraxx. I have an oscilloscope and I looked at the motor leads and zero voltage. I put 12 volts DC to the motor connector on the loco and the motor is fine. The decoder is good for 0.75 amp and the maximum the motor draws is 0.45 amp with the drivers held stopped.
You might be interested in knowing a working SoundTraxx decoder puts out pulse power to the motor, not DC voltage. The light functions are straight DC. I did a series of checks with the Oscope.
Here is a photo of the 4-4-0 PC board. I removed the three capacitors and the two inductors.
Just to touch base with this topic some more.
I talked to the gurus up in Denver's Caboose Hobbies yesterday and they told me that if you hard wire the decoder into the tender, before you snip the Spectrum colored wires soldered onto the printed circuit board, the printed circuit board should have imprinted letters to ID what the wire is for.
For example, the letter M should denote one of the engines motor connections, and there is an LED connection also imprinted. So that helps. Im not as blind as I had thought.
So even with any possible wire color combinations that exist, the answer is right in front of us.
Do I have to use a 750 Ohm resistor for the LED, do you think I could get away with a 1K Ohm resistor for it?
And on the best part of this - Caboose Hobbies told me that if I had any trouble at all to just bring in my loco and they will tutor me on how to do this. They wont do it themselves, but will teach me how to finish this off and if I need any materials I am responsible for that cost alone.
Gee's, all of us are winners when a model train stores treat the community like that.
Mike Webber
Colorado
a warning to anyone trying to install decoders in bachmann spectrum steamers ...
i assume they have the engines made in more than one factory , because the wiring isn't always the same from model to model even if they're the same type . always check the wiring on your model before installing
p.s. excellent tutorial , thanks !
mdwebber wrote:Got it Rich and thanks.Do you know if this is different for the Spectrum 4-6-0's?I have one of those I am about to start with another light steam decoder.Thanks for your time -Mike Webber
Got it Rich and thanks.
Do you know if this is different for the Spectrum 4-6-0's?
I have one of those I am about to start with another light steam decoder.
Thanks for your time -
I do not know. I wll look around though. Notice the comment on high drivers versus low drivers.
http://www.tonystrains.com/tonystips/2003/032703.htm
I just looked at http://www.bachmanntrains.com/home-usa/dwg/dwgs/H823-IS001.PDF
and the tender frame has no holes for sound. THis could be more challenging. The 4-4-0 came with speaker holes. This may change with the new line of 4-6-0s. If you do not have one yet, they will be $208 at Micro Mark with a Tsunami, though the one in the Spectrum will have a few less sound options but still very acceptable.
I have spoken with someone who did the Micro install and keeping the PC board. He unplugged the stock decoder and plugged in a Micro. He had to solder the seven wires to a 8 pin NMRA plug first. If you go with the PC board, clip the three capacitors, C!, C2, C3.
I kept the PC boards with my Roundhouse steamers.
I removed the PC board because I first installed a DSD-100LC decoder which is a little larger.
I removed the DSD one and installed the Micro, a much better decoder.
Don't ever use a DC power supply to check connections. Notice the person who suggested to use a power supply to checkout the boiler wires. NO DETAILS. Details can bite. You could burn out the LED headlight, been there done that. I forgot about putting in a resistor with the decoder. Most people use the ohm meter on a digital volt meter. They are not expensive, Rat Shack, Home Depot, Lowe's.
I have been a electronic tech for many years so it is second nature to me. I have also been a machine mechanic and when you power up 480 three phase motor systems, you can quite a rude awakening if wired incorrectly.
Make sure you have a resistor for the LED headlight. If the light does not come on, reverse the two leads.
If the drivers are running in reverse with the DCC controller, reverse the two motor wires.
Make sure the tender trucks are in the same position or when you plug in the loco, you will get a short when the DCC is turned on. Someone on a Yahoo Bachmann DCC group did just that a couple days ago.
Again, I always use an ohm meter to ring out everything before powering up.
Rich - would you be able to list what the wire color translation between the micro tsunami and the spectrum wire colors are? I am having problems trying to figure out what micro tsunami colored wires go where since Bachmanns wiring scheme doesnt make sense to me?
Thanks -
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Hello AllI just installed a SoundTraxx Micro-Tsunami decoder in my Richmond. I bought the engine Jan 2007 and had installed a SoundTraxx DSD-100LC decoder. The Micro is a much better decoder for speed control and sound.Bachmann is getting ready to release the Rcihmond with sound for $400.00 retail.The loco cost me $130.00 over a year ago. Now they are going for $60 to $100, new.The Bachmann tenders only pickup one one side of the trucks. I added pickups and now all eight wheels have pickups.I painted the wires with liquid black vinyl tape substitute to make them look like hoses.Right now I have removed the ugly couplers from the loco and tender and I am going to install the Kadee #711 old time coupler.
Here are three photos of the nearly comleted loco. I installed a box headlight and Kadee old time 711 couplers. The Micro decoder is a big change from the DSD-100LC installed a little over a year ago. I could not wait until Bachmann was going to put sound in it.