Bachmann Alco S-4 & Decoder problems

[MP2626]

I would have purchased the Bachmann S-4 Sound Value model had it been offered in Northern Pacific livery.  Since it was not, I have provided it with a Digitrax DH123D decoder.  I have installed a dozen or so of Digitrax Decoders and never had a problem.  I noticed that Bachmann wires their motors with the red leads from the track on the fireman's side, whereas others would have the red leads on the engineer's side, however, this makes no difference.

After completing the installation I placed the loco on my programing track and got a d nd error message on my Digitrax Zephyr DCS50, meaning there was an open circuit on the programing track.  I got out my Multimeter and checked continuity between the wheels and decoder and found that one of my solder joints had broken apart.  I fixed this and rechecked the continuity and it was good.  Then I placed the loco back on the programing track and attempted to read back the address and got 03, which was what I had hoped I would see.  I attempted to run the loco on address 03 and nothing happened!  I placed the loco back on the programing track and attempted to write the mew address (713) and now get a d nA error meaning there is no acknowledgement from the decoder. I also at one time got an A255 message and I am unfamiliar with this one.

I have always been successful before, installing decoders.  However this one has put me at a loss.

Anyone have any suggestions?

Thanks in advance!   

[Len]

The '255' sounds like a value read back for some CV. It's not a DCS50 error message I'm aware of.

Just to touch base on a basic, if you check CV29 do you get a value of either 34 or 38? It should be one or the other for a 4-digit address.

Len

[Hunt]

An error message of A255 brings two usual suspects to mind
   1)   You tried to reset all the decoder CVs to their factory default value (program CV 08 with 08 ) and reset was not complete before another command sent to decoder.
   2)   A decoder internal circuit problem

Since your are using Digitrax DCC system and decoder suggest you contact Digitrax.

[MP2626]

An error message of A255 brings two usual suspects to mind
   1)   You tried to reset all the decoder CVs to their factory default value (program CV 08 with 08 ) and reset was not complete before another command sent to decoder.
   2)   A decoder internal circuit problem

Since your are using Digitrax DCC system and decoder suggest you contact Digitrax.

1) Brand new decoder and never did anything to other than as mentioned in my initial post.

2) Possibly, I have another DH123D decoder and I will exchange and see if that fixes the problem, tomorrow.

I already have sent an email.  Thanks for your suggestions!

Mark 

[MP2626]

The '255' sounds like a value read back for some CV. It's not a DCS50 error message I'm aware of.

Just to touch base on a basic, if you check CV29 do you get a value of either 34 or 38? It should be one or the other for a 4-digit address.

Len

As just stated above I will do some testing tomorrow and I will check CV 29.

[MP2626]

I found I had another open circuit, this one was on the gray wire from the decoder to the motor.  The loco was re-addressed to 713 and took the new address.  I checked CV 29 and the value shown was 38.  The light do not work, I assume I need to add resisters to fix this, does that sound right?

[ACY]

The light do not work, I assume I need to add resisters to fix this, does that sound right?

They may need to be replaced.

[MP2626]

The light do not work, I assume I need to add resisters to fix this, does that sound right?

They may need to be replaced.

Why would they need to be replaced?

[Len]

If the loco was not "DCC Ready" it may have had 1.5V bulbs installed. In which case, without a dropping resistor, the 12V light circuit from the decoder would fry them in short order.

Len

[Hunt]

BTW-
Bachmann current product Alco S-4 without Sound Value decoder factory installed is DCC ready, both lights are LED.

See http://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=66_68_573&products_id=7118

[Len]

Is there a current limiting resistor built into the light assembly?

If not, same as with a 1.5V bulb, the LED may have been fried with the hardwired DH123D installation the OP mentioned. Which makes me wonder why hardwire in a 'DCC Ready' loco?

Len

[MP2626]

Is there a current limiting resistor built into the light assembly?

If not, same as with a 1.5V bulb, the LED may have been fried with the hardwired DH123D installation the OP mentioned. Which makes me wonder why hardwire in a 'DCC Ready' loco?

Len

When I emailed Digitrax, questioning about a drop in decoder for this loco, Digitrax could not reference a decoder that would just drop in.   So, I had a  DH123D, which is a good generic decoder for this application and used that.  Missing that I was going to need a dropping resistor was a mistake on my part.  I had foolishly thought that because it was supposed to be DCC ready all I had to do was add a decoder and that the resistor must have been a part of the LED assembly.  My bad!  I also wondered, if the loco is supposed to be DCC ready, why where the back-up lights soldered to the PC Board? 

[Len]

From the description of the S-4 without "Sound Value":

Bachmann is pleased to offer the S4 in this DCC-ready model with factory-installed 8-pin socket for the DCC decoder installation of your choice.

Any 8-pin, or 9-pin decoder with an 8-pin plug on the harness, e.g., DH123PS, should have been a simple install with no soldering involved. The 9-pin to 8-pin harnesses are available separately in short, medium, and long sizes.

Len

[MP2626]

Thank you to whom ever removed the last few posts to this thread!  So, at this point I have an Alco S-4 in N.P. livery and a DCC decoder that works, my lights don't function; but, I can fix that.  I would like to thank those who made suggestion and helped me out! 

[Bucksco]

Your welcome. We need to keep things civil.....