For those that have trouble with their new sound-equipped SD45 with the sound and motor cutting out, I'm trying to develop a solution.
So I made a picture of the underside of the Soundtraxx Circuit Board. I think I might have identified the bridge rectifier. On the underside of the circuit board is a group of four small black rectangles arranged in two groups of two (or is it two groups of two?). If I put a multimeter from the left side track input to one of the eight solder points on those black rectangles, I get a very low resistance, something like 0.2 ohms. Is that where I'm supposed to connect the negative (DC negative) of the capacitor bank (according to the website below)? And the positive would normally go to the blue wire, but since we don't have a blue wire, the blue connections are to functions, which in this case are the front and rear lights. I'm guessing the positive of the capacitor would connect to the + positive pads on the front or rear LEDs (where it says V+ on the top front and top rear of the circuit board).http://www.members.optusnet.com.au/mainnorth/alive.htmI'll upload a picture when I get home, but I'm talking about point 2 once the picture is uploaded.
You will see two cathodes tied together and two anodes tied together. You will see 12 to 14 VDC and the leads will connect to a square filter capacitor nearby. Probably the largest cap.
Not sure you will need the diode and resistor. I read a post in a forum but cannot remember where that someone did this in N scale and did not need the resistor and diode.
Older Stay alive page in case you have not seen it yet. Mostly HO scale decoders though.
http://wayback.archive.org/web/20120729061658/http:/www.members.optusnet.com.au/mainnorth/alive.htm
No idea your level of electronic experience. Full wave bridge rectifiers below.
http://tinyurl.com/jhgyqyl
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.
The large silver circles are capacitors that are cylinders that go into the frame of the diesel.
Rich,
I'm not sure how to identify the anode (+) or the cathode. There are little bars on the four diodes, not sure whether or not they're the anode or cathode.
Very easy. Look with your voltmeter. Anode is positive, cathode is negative.
Google search would tell you the same. That is why I posted the link for full wave bridge rectifiers. Symbols right on the devices.
You should have two of the below meters. I have four of them.
Needed when you work at the component level.
http://www.trainelectronics.com/Meter_Workshop/index.htm
http://www.trainelectronics.com/Meter_HF/index.htm
When the meter show positive 12 volts, the red probe is on positive connection..
If you see -12 volts, the red lead is on the minus connection.
Don't mean to talk down to you. Just thinking you do not have a meter.
Mine read 13.6 VAC for my NCE Power Cab.
Rich, thank you. I have the Powercab also.
So how do I use my multimeter to find out which solder pads to connect the capacitor to?
The marked side of the diodes is the cathode. The junction of two cathodes will be your - side for the cap. The blue wire, or function common, before any current limiting, if it's built in to the board, is the + for a keep alive cap. You should be able to measure DC volts across these points and get something around 12V, depending on your track voltage.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Ok, I assume you have the sound version.
I just looked at the Bachmann site for this loco and the decoder for DCC non sound onboard is quite different and easier to figure out. The sound version decoder comes from SoundTraxx and have not found any description of it so far. To my knowledege, SoundTraxx has a cap for stay alive for sound not motor operation. When people ad caps, it is for motor operation. I have done that and a couple of my HO with on board sound have a 220 ufd cap included with the decoder connected by two wires.
Looks like you might need an Optivisor, magnifier to look at the diodes and PC board traces. Look for two diodes that have the traces connected together, Your ohm meter will show zero resistance when the probes are at the proper cathode connections. Same with the anode connections. The two traces will lead to a cap. The traces should have a prefix for each component.
Supporting the PC board might be a challenge if you want to check voltage. Best I can do unless someone here has done it.
You can also join the Bachmann N scale forum and ask.
http://www.bachmanntrains.com/home-usa/board/index.php/board,3.0.html
According to Soundtraxx documentation, the resistor goes on the function wire (white, yellow, etc.), not the common (blue).
gatrhumpy According to Soundtraxx documentation, the resistor goes on the function wire (white, yellow, etc.), not the common (blue).
Resistor for lighting. I have done both ways. Only the proper polarity is important with LED's.
So pins 1 and 2 are connected and 7 and 8 are connected. Pins 3 and 4 and NOT connected together and 5 and 6 are NOT connected together.
So pin 5 is also connected to the end of the diode that is closest to pin 5 (not pin 6).
So pin 2 has the cathode (bar) as well as pin 8. So do I connect the capacitor to pin 2 or pin 8? Both are cathodes. The right track connection is connected to pin 7 (anode), and the left track connection is connected to pin 2 (cathode).
I'm guessing I have to connect the negative of the capacitor bank to pin 8 (-) because pin 2 (-) is connected to the left track connection, which is an input.So according to my diagram above, here is what I've discovered:Pin 1 (anode or +)Pin 2 (cathode or -)Pin 3 (cathode or -)Pin 4 (anode or +)Pin 5 (cathode or -)Pin 6 (anode or +)Pin 7 (anode or +)Pin 8 (cathode or -)Pairings (or which pins are connected to other pins)1 and 2 are connected together3 and 5 are connected together4 and 6 are connected together7 and 8 are connected togetherAC (or DCC) inputs go to pins 2 (-) and 7 (+).
Sorry, you lost me. You mentioned resistor connection and then went on to pins.
I will leave this for others.
I'm looking at the picture that I posted and explaining how each side of the diodes are connected.
IF your list is correct, the junction of 4 and 6 is the - for a keep alive cap.
How big of a capacitor do you plan on connecting here? It has to be pretty substantial to actually give any sort of keep alive action, and the voltage rating needs to be 16V or better. I'd really do a 25V cap (that's the next standard step up from 16). If you are thinking about using a supercap, you definitely need the diode and resistor, or the inrush current will be too great.
Or just connect a commercial keep alive to those points.
I have several capacitors marked 227 on them. It's 220,000,000pF. I plan on connecting five of them. Four of them on my Kato SD40-2 will allow the lights to gradually dim when connected to my ESU LokSound Select Micro DCC sound decoder.
I have heard several reports of people returning these things to Bachmann because the sound keeps cutting out. I seriously doubt it's a pickup issue. I think this is a decoder issue.
Actual Soundtraxx decoders come with a capacitor on them which powers only the sound in the event of momentary dropouts. Did maybe they leave this out as part of the bachmann "value" version? Or to make it fit in an N scale loco.
Sure you can, if the loco is big enough. Good luck with an N scale SW or something.
Add track wipers to each truck, that might be all it really needs.
Keep the track clean, use Electrofrog turnouts. No dead spots.
Not about to try, but the way my friend is able to fit a motor and a motor decoder in a SMALL N scale slope back tender is simply amazing. I don't even know how I would strip such short pieces of wire, too short for my fingers to even grab on to. No sound of course, the tender is 100% full with the motor and some of the smallest decoders you can buy, like the CT Elektronic ones. Boiler is full of lead except where the gearbox is so these little things can actually pull decent trains on hills. The space inside an SD45 is huge in comparison.
gatrhumpy:
I sent you a PM.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
I heard back from Soundtraxx, and they e-mailed me the following statement: "I'm surprised to hear that you're having trouble with this engine and the sound cutting out. There are no dedicated solder pads to solder the CurrentKeeper to, so the best thing is to solder more capacitors to the two 100 uF silver can capacitors that are already on the engine. Hope this helps!"
[Edited by Forum admin]
Here's the thing - you can't just parallel the caps to add more, that cuts the voltage in half while indeed doubling the capacitance. Series doubles the voltage but halves the capacitance. So you'd need to add a total of 6 more capacitors, unless the existing ones are already series or parallel with each other. Or replace the existing ones with larger values.
Those capacitors on Soundtraxx decoders ONLY power the sounds, they do not keep the motor moving like a keep alive. As long as the motor can mechanically coast past the dead spot, larger capacitors shoul dkeep the sound from dropping. If the loco stalls, not just drops the sound, this will fix nothing. Better pickups are needed. There's no excuse for such a relatively large loco having problems even on dead frogs.
Just because I'm not around to monitor the Forums on weekends doesn't mean I enjoy coming back on Monday to find I have to clean up a pissing match. This thread has been cleaned up. Next time this happens, there will be suspensions or worse. You should know better.
--Steven Otte, Model Railroader senior associate editorsotte@kalmbach.com
Hello I am new here.
I just purchased one of these and everytime it stalled i tapped my table it was on and it came back on.
Has anyone attecpted to directly run a wire from the wiper to the posts where the decoder is mounted.
I was thinking about doing it but wanted to see if anyone has done it.
Yes, and that did not make a difference.
Randy, if you add capacitors in parallel, it increases the capacitance but does nothing with the voltage of each capacitor. Each capacitor still sees the same voltage. That's only with resistors.