Maybe a bad decoder?

[MilwRoader_Steve]

Greetings all -

Bought an Atlas Masterline Silver Alco S-2 at a show, Sat. SUpposedly DCC ESU equipped. Took it to a club display and they were nice to trial it for me. Would not run DCC on addresses 03 or cab number. Did run on the DC track.

Had the correct Digitrax DZ126PS decoder that I bought for another application so opened the shell. Verified that it had no decoder but that it did have a speaker installed. The 8 pin socket had no plug or blank. I installed the decoder and put it on the program track.

Running Digitrax Zephyr DCS52. Getting a "No decoder ack pulse" message which I believe means that the command station does not see/communicate with the decoder.

I wonder if the factory installed ESU decoder was pulled; also wonder if my decoder is bad from the factory or I goobered it somehow. LHS closed Monday so will go by Tues or Wed and see if he has a decoder tester (?) or just buy a new one.

I would much appreciate any suggestions.

 

[MilwRoader_Steve]

Here are some pictures to help. Thanks all

 

[MilwRoader_Steve]

Steve, Atlas Silver as far as I know is DCC ready only. Newer models may have a speaker pre-installed for the end user to put their own sound decoder in.
In any case, there is no decoder in that engine.
Also, looking at the photos, the negative lead to the motor is not connected. Without the decoder being able to pulse the motor, it won’t do a proper readback to the programmer.

Would you please flag the negative lead to the motor? I'll look more carefully, too. Thanks Terry!

 

[bnsf971]

It's tough on my tablet, but it's the one marked "M-" on the board. It looks like the plastic clip to hold the wire in place is melted, and there's no wire there.

 

[Rico]

I think Terry has something there.
I’d also trim up the wire strands on the spk terminals as well in case they short out.

 

[J.Albert]

Someone has mounted a sound-capable decoder under the factory installed "green board".
Looks like they used some of the connections ON the green board, as well.

 

[tootnkumin]

Someone has mounted a sound-capable decoder under the factory installed "green board".
Looks like they used some of the connections ON the green board, as well.

That does look like what is going on there. Personally, if I am doing a DCC ready lighting board to DCC/sound decoder installation, I scrap the lighting board and use the sound decoders wiring or connections directly to the functions they apply to. Instructions as to which wire or connection on the new decoder go where have an illustration or wiring color code with them if bought new. Space above a motor is usually limited and the removal of as much doubling up of circuitry as possible is advantageous.

 

[MilwRoader_Steve]

Someone has mounted a sound-capable decoder under the factory installed "green board".
Looks like they used some of the connections ON the green board, as well.

I am fairly sure that is a factory install. I reached out to Atlas for help, but all they could provide is this e-copy of the exploded parts diagram. I had the paper copy with the locomotive. Thanks, though.

I did inquire whether they could send a electronic schematic - answer was 'no.'

To Terry's observation: I think you may be right, but I can find no loose wires. One wire connector cap thingy (I don't know the technical term for those slip on wire connectors) was loose and fell out of the shell when I first opened it. But I find no loose wires! There are those two blacks and two reds joined together, but those connections look, to me anyway, like factory.

Further, when I apply power to the rear axles, I get lights only. When I apply power to the front axles, I get motor. This I tested using the Kadee powered wheel cleaner. That bespeaks wierdness, but I am stumped as to what to do.

I tried putting the loco on the main track, removing all other locos and send the CV08 reset via program on the main, but to no avail.

If the ESU decoder is indeed that lower 'sound board' - it has a strange address. Neither 03 nor the cab number.

Thanks all for your help, I really want this thing to go!