Atlas Dash8-4CW and DCC

Quick question, has any experienced any "weird" issues after installing a decoder into the new Atlas dash 8 silver series? Here is my issue, in that I have two of these units (very nice) and went to install the NCE D15SRP's into them. After programming them, they are running in reverse, both of them. I made sure twice, that I have the decoder set for "normal", not "reverse" operation, but no luck. I'm using a NCE PHP unit for my layout. Has anyone else noticed this? I know that I can set the decoder into "reverse" mode, but that would be confusing later on when I go and MU units.

Any help would be appreciated.

I haven't had the opportunity to try this, but in the past, when I went to replace an older Atlas decoder with one made by NCE, I noticed that the motor connections were exactly the reverse. It is possible that Atlas simply turned their decoders front to back, when a new decoder was installed, it also had to be turned front to back to get the correct orientation of the motor wires.

Have you tried inserting the DCC plug in the opposite orientation? If you lose your lights, you know that this didn't work...

Frank,

Actually, this is the new silver series, which has the 8pin dcc plug already to go, no decoder. I can switch the pins around and see if that corrects it. Thanks for the option. I will repost with results shortly.

Here's another possibility: According to the dox for this decoder, CV29 defaults to 2, and the only way I can see how this works is if bit 0 is set to 1 and bit 1 is set to 1, which would mean that direction is reversed. It's certainly a strange way to configure a decoder at the factory!

bit 0 1= direction of operation is reversed, 0= direction is normal bit 2 1= analog operation mode enabled, 0 = disabled bit 4 1= alternate speed table active, 0= use table defined by CV2,5,6 bit 5 1= use long address in CV17/18, 0= use short address CV1

In the D13SR, the default is still 2, but I can see how this would be an acceptable default w/o reversing directions: The 2 necessary bits are 1 and

2 (see below). Setting these on at the factory would enable 28 speed mode and analog operation.

bit 0 1= direction of operation is reversed, 0= direction is normal bit 1 1=28 speed mode (always enabled) bit 2 1= analog operation mode enabled, 0 = disabled bit 4 1= alternate speed table active, 0= use table defined by CV2,5,6 bit 5 1= use long address in CV17/18, 0= use short address CV1

Frank,

Took your suggestion and turned the decode pin around. The unit runs in the correct direction, but without any lights. I would say that you were correct in your first assessment that Atlas reversed the motor connections. The wires from the motor to the J3 on the printed circuit board, as black then red on the connection. Hopefully, I can just redo the connection plug by reversing the wires.

Yes, I understand that this is the new version that allows you to use your own decoder. I only mentioned that in case this is another locomotive in which the motor connections are reversed.

BTW, please ignore my follow-up post about CV29. I realize now that if Bit 1 is set, it would have to be set to 2. Therefore, the default setting is correct for a 28-128 speed step system, and direction is NOT affected.

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Forget altering the wiring or any other complications, CV29 is there to save you the trouble, just change CV29 from 2 to 3, (If 2 is the default) or if the CV29 default is any even number add 1 to it, if its already an odd number subtracy one from it. Tghis will correct your direction so 'forward' is correct. It doesn't affect mu operation. Keith

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Gee, never thot I'd have to use machine language just to get a freakin' loco to run. Had enough bit flippin' at intel with PCI tools. What a pain!