# Sd70 mac doa



## oldrk (Dec 25, 2013)

I got a SD70MAC by USA Trains on the bay and when it arrived it wouldn't do anything once set on the track and power applied. And yes the switches are set for track power. I pulled the pins on the trucks and applied power there and the motors ran fine. Any ideas? It appears to never have been run by the shine on the wheels and over all appearance.


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## s-4 (Jan 2, 2008)

Will other engines run if it's on the track? 
If not, maybe there's a simple short circuit...
For instance, the input power plugs could be installed in the wrong terminals?


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## oldrk (Dec 25, 2013)

Sat on the track with a SD40-2 and it did nothing while the SD40-2 worked fine. Not even the lights come on.


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## Totalwrecker (Feb 26, 2009)

Are the wheels and wipers clean?
Try flipping switches with power on, maybe missed wired

John


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## ewarhol (Mar 3, 2014)

Trying to start simple before getting complex. While I don't have a USAT SD70, I do have a NW-2 and a SD40-2. Both those engines have slide switches for turning motors, lights, and smoke unit on/off. The SD40-2 is underneath the locomotive between the fuel tank and one of the trucks. The NW-2 switches are located at the front of the engine where a hood flips up. Does the SD70 have anything like this?

You said all switches were set, but wasn't sure if that was track switches or the power switches on the engine.


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## chuck n (Jan 2, 2008)

I have two of these. There is a motor switch on the bottom, where you said it is on the SD40. I have not seen a track power switch. If there is, I'd like to know where it is. I wish Charlie would have his otherwise excellent engines wired for a battery/track choice.

Chuck


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## Greg Elmassian (Jan 3, 2008)

Open it up.... sorry...

Greg


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## oldrk (Dec 25, 2013)

Wheels are shiny new. I have attached alligator clips to sliders and also tried touching them to the wheels. No luck. There are four switches Motor,lights,smoke and sound. The Motor and light switches are set to ON.


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## SD90WLMT (Feb 16, 2010)

Like Greg offered here...yer gunna have to remove the cab and hood unit off the chassis..

Are all 4 wires hooked to eack motor block...2 - power, 2 - track power feed....

You bought this off Ebay....it's a used or New item?????

Has it been converted to battery power...?

We're mostly In the dark here....taking the easy way is not solving your issues...
We can help....but.....

.. :-D


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## rntfrmme (May 23, 2013)

Same thing happened to me. I bought a very new looking USA trains GP9. wouldn't run or do anything. Opened it up and found an airwire drop in board, huge 18v battery, with a phoenix sound system. Bought a remote throttle managed to get it programmed and it worked fine. Sounds like you need to open it up as others have suggested.....

Bill


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## oldrk (Dec 25, 2013)

*sigh* I guess I will pull the shell and see what gives.


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## JackM (Jul 29, 2008)

I don't mean to insult anyone's intelligence here, but I don't see any mention of "DC or DCC?".

JackM


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## Totalwrecker (Feb 26, 2009)

JackM said:


> I don't mean to insult anyone's intelligence here, but I don't see any mention of "DC or DCC?".
> 
> JackM



That's why all said to open the unit, can't see DCC from outside...

BTW? saying you don't mean to insult, does not stop the insult, just softens your 'guilt'.....

Happy Rails
John


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## JackM (Jul 29, 2008)

Guess I have to use a 21st Century cliche with the same meaning:

"Jus sayin'"

JackM


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## Dan Pierce (Jan 2, 2008)

To test for a decoder, I use a 30 ohm resistor in series with my track feed.
If front and rear lights turn on and motor buzzes, definitely no decoder present.

If this did not occur, then I try to read cv29 and cv 8.

CV29 for what speed steps and addressing, then cv8 for manufacturer.

PS, I had a brand new engine from LGB that did not work on DC and it was CV29 set for digital only and 28 speed steps.


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## Greg Elmassian (Jan 3, 2008)

For used locosk, I used to just try applying power. I had a procedure like Dan. Now, I open the loco and check it out visually, and verify the main wiring paths with a meter.

Less smoke.

Greg


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## oldrk (Dec 25, 2013)

OK, I grew a set and pulled the shell. Sure enough, a wireless receiver. No battery so it must get power from the track. One thing I found interesting is under the fuel tank when I removed it was a momentary pushbutton that is wired in with the decoder. Could it be the push button somehow bypasses the decoder?


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## Dan Pierce (Jan 2, 2008)

The push button is most likely a reset for programming the decoder.
Aristocraft/crest had this on the 75 mhz receivers.
CRE55491/CRE55492 for the receiver and transmitter and documents from Aristocraft.

A picture of the board would let one of us get back to you on manufacturer.


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## armorsmith (Jun 1, 2008)

Similar to what Bill stated above, I purchased a USA GP9 off eBay, and when I received it, it ran fine - with sound - not listed in the listing. When I opened it up, it had a Phoenix sound card installed that was worth more than I paid for the engine. EBay is a wonderful place to get usually good deals, but one must always keep in mind that there are those selling on eBay who have no earthly idea WHAT they are selling. I agree with others above that solving your issue with this loco is going to take more than words. I believe you will need to open it up and investigate deeper.
Depending on where you are locate, if your confidence to open it up is a bit weak, look for a club or association in your area. I am sure there are folks there that are well heeled in the assistance you need.

You will need to contact Crest Electronics, AristoCraft is no longer in business.

Good luck, Bob C.


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## Greg Elmassian (Jan 3, 2008)

Bob, he has not indicated what the mfg of the decoder is yet.

It was Dan who indicated that the Crest stuff had a pushbutton.

old rk, nice high resolution pix please... if you cannot post, email to me (my email address is in my sig)

Greg


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## oldrk (Dec 25, 2013)

http://www.trainboard.com/railimages/showphoto.php/photo/165709/title/sd70mac/cat/507

http://www.trainboard.com/railimages/showphoto.php/photo/165712/title/sd70mac/cat/507

HERE IT IS.


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## Greg Elmassian (Jan 3, 2008)

Aristo Revolution, looks like standard one without sound.

Can be wired to run from track power

Won't move unless you have the transmitter.

Take it out and put in the shorting plug for DC operation, or buy a transmitter to run it from the track.

Greg


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## East Broad Top (Dec 29, 2007)

That's the Aristo/Crest "Revolution" receiver. The little board on the left of the photo is the smoke or high-current light (incandescent) control board. 

Red - power in
Orange - motor out
White - headlight ground
Blue - common + to headlight and backup light
Yellow - backup light
Grey - motor out
Black - power in

The smaller plug on the right of the board is the auxiliary control wiring harness. The black is ground, and each of the colored wires correspond to the 6 functions on the Revolution transmitter. From what I can tell, you've got the brown wire going to the smoke/light board, and it doesn't look like any of the other functions are wired to anything that I can see. 

If you want to run this loco off of track power, you can remove the Revo board altogether. Connect the power from the track (connected to the red and black wires on the Revo board) to the power going to the motors (orange and grey). You can also wire the smoke directly to this, and the smoke unit will also work off of track power.

I do not know how the lights in this loco are wired, so I'm not sure how you'd go to getting them to run off of track power. It could be as simple as wiring the lead attached to the blue wire to one rail and the white/yellow to the other, but without looking at it, that's a somewhat uneducated guess. 

Good luck!

Later,

K


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## SD90WLMT (Feb 16, 2010)

USA SD70 smoke boards are located in the upper hood..at the exhaust location. ..

Smoke unit....and small board....

....clarification...


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## Greg Elmassian (Jan 3, 2008)

I cannot see where the red and black inputs to the Revo go, exactly, but they appear to go to the track pickups.

On the lighting, most modern USAT locos have low voltage incandescent lamps in a few locations, and some LEDs. I don't have one of these locos, but quite a few other USAT and the voltages that run the lamps are all over the map.

Most people wind up burning out the lamps or give up in frustration and replace with LEDs.


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## oldrk (Dec 25, 2013)

I have been wanting to go wireless anyway. So I would need a battery(that's the way I want to go) and the throttle and I should be ready to go once the battery is wired in?


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## East Broad Top (Dec 29, 2007)

In the most simple terms, yes. You would put the battery somewhere in the loco, hook the wires from the battery to the red/black wires going to the Revolution, and you'd be all set. If you can't remove the battery to charge it, you'll want to place a charging jack someplace on the locomotive, and also a power switch. I always add a 5-amp fuse as well. Cheap insurance. 

Make sure there's no connection between the battery and the wires going to the track pick-ups, which--if you wire the power from the battery to the red/black wires after cutting the other ones off, there shouldn't be. 

I'm not a huge fan of running smoke units off of batteries, as they're just a drain, but you can if you'd like. 

Later,

K


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## Greg Elmassian (Jan 3, 2008)

yep


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## oldrk (Dec 25, 2013)

I went to the Crest page and looked at the receivers and they don't look exactly the same. The ones on the page has a couple of large blue capacitors where as mine doesn't. Also, if I hook up a battery how does the throttle and receiver know to communicate? Also I have a battery I found in a used tender. I will get a picture and post it.


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## Greg Elmassian (Jan 3, 2008)

Reference my post #22.

The older style did not have sound, the new ones do.

All the new ones have sound.

Greg


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