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Discussion Boards => General Discussion => Topic started by: *hobby* on February 26, 2008, 12:21:36 AM



Title: Strange Decoder Behavior in New DCC Spectrum 2-8-0
Post by: *hobby* on February 26, 2008, 12:21:36 AM
I'm posting this in case it might help someone else avoid a little frustration. I just received my first Bachmann HO loco with a DCC decoder (UP 2-8-0 ) and it acted strangely from the start. I'm pretty familiar with DCC and have a dozen or so engines with sound and non-sound decoders but I've never had one  behaving as oddly as this one.  The first time I tried to run it was under DCC and I found the direction was reversed - forward setting on my Digitrax Zephyr ran the loco in reverse. It also ran poorly in reverse with a lot of jerking at low speeds and requiring much more throttle than running forward.

I decided to try to change the address from the default 3 but it wouldn't take either 618, it's road number, in 4 digit mode or 18 in two digit mode. I tried this multiple times both with and without a 1000 ohm resister on the programming track. But an odd thing happened when I retried it on the powered track - it now ran in the correct direction! I guess the attempts at entering the 4 digit address corrected a mis-setting in CV29 even though the long address didn't take effect. Operation was still very bad in reverse, however.

I then tried running it on DC and found that it would not run at all in reverse nor did either headlight work while on DC. At this point I thought I had a real dud on my hands and, even though it arrived in shrink wrap, I was wondering if I had gotten someone else's defective return along with their scrambled decoder settings.   Fortunately, I tried once more to set the 4 digit address after finding someone's post with a link to the Bachmann decoder CV settings. This time I individually set CV 17 to 194, CV 18 to 106 and CV 29 to 38. Back on the mainline it now responded to #618 and even seemed to run a little better  in reverse.

I then tried it again on DC. Amazingly, it was now able to run in reverse as well as forward and the headlights (as dim as they are) worked! About 30 minutes running in reverse on my loco test stand made even the slow speed performance improve dramatically.  It might make a good switcher after all.

I am still not sure how the decoder could have gotten so messed up but I'm delighted to get the big issues resolved. I think Bachmann does a great disservice to it's customers by not having some clear information on their CV settings in the documentation included with the model.   They should at the very  least document how to do a reset  and suggest a reset  if there's any operational weirdness  like I experienced.  All of the other DCC-equipped locos I have purchased included at least the common CV settings and reset suggestion.

All in all I do like the engine now that it's working reasonably well. It has very good pulling power and looks pretty nice. The number boards are rather crudely done though and look just like stickers instead of real number boards. Mine also arrived with one of the tender railings broken off at the rear of the coal bunker - how you can break that very flexible plastic is also kind of surprising. Anyway, I will be thinking about upgrading the decoder to something that provides better low speed performance but I'll probably wait to see if it improves enough  with some more break-in time.

Charles


Title: Re: Strange Decoder Behavior in New DCC Spectrum 2-8-0
Post by: Yampa Bob on February 28, 2008, 08:18:45 PM
Charles
I have 3 of the #618 and never had a problem.  However I ran them on  DC power for about an hour for a thorough breakin before even trying them on DCC.  If any problem is detected on DC, and I can't find a quick solution, it goes back for exchange or refund.

Since the decoder is bypassed in DC operation,  and the lights did not work, I would suspect something in the DC compatibility board. 

My DCC is an EZC,  again if I detect any problems back it goes.  One shouldn't have to fiddle with CVs out of the box.  The fact that the railings were broke was sufficient cause for exchange. 

Glad you got it running ok, you certainly have more patience than I.

Bob