Modeler in need of DCC assistance............

[LIRR]

I am a DCC novice. Electricity in general is not my favorite part of the hobby….need some help from the experts….

I bought an Atlas S4 (HO) about a year ago. I liked enough to quickly buy a second one.  I added a short line extension to my RR and operated these paired. They have Loksound V5 decoders. Until a couple of weeks ago they ran beautifully. Then one started giving me trouble. Classic symptoms of dirty wheels and/or track. Cleaned all, this wasn’t the problem. It wouldn’t move. Gave it a push…it would move along. Sporadic and erratic occurrences. Reprogrammed it. I didn’t write it down but I recall some of the CVs had hanged – or I could be misremembering this. Seemed to have fixed the problem for a while.  Soon reoccurred. I then reset the decoder to factory settings. Didn’t help.

 The loco powers up. Lights, sounds, bell all work. It won’t move. Sound revs up when I increase the throttle, but it won’t move.

I am open to an and all suggestions……

[Peachymike]

Have you check the motor in the loco and drivetrain?  This sounds like a common problem I see with both DCC and straight DC units. Depending on the hours or conditions it is run under it could be a sticky or worn brush. If you are comfortable with taking the shell off to access the decoder you could check the output from the decoder with a voltmeter. The output is pwm but should still give you a steady, even increase in voltage as you increase speed. Alternately you could play swap and change the decoder form one engine to the other ( assuming it is plug and play), if the problem stays with the first same engine then there is a problem with its motor or mechanical drive, if the problem moves with the decoder then then decoder is to blame.
Peteski is a master at troubleshooting and mapping the decoders, maybe he will chime in with some suggestions.
Mike

[woodone]

Could you provide a bit more information has to your system?
Who's command station are you using?
Did you check you track connections?
It does sound like a dirty track/wheel problem.
Make sure your wheels are clean.

[Jim Starbuck]

After making sure the wheels are clean look to see if F9 has been accidentally activated.
That is drive hold and will give the condition you described as sound notches up but the engine doesn’t move.

[LIRR]

Thanks everyone…..

 
i think I’m back in business. I think the first problem was the big U. User error. I didn’t realize the momentum function on the procab actually changed the acceleration/deceleration CVs. That was the change I noticed when i first reprogrammed. Acceleration interval was maxed out. But only on the 1 loco-not the  consist. That would explain why it wasn’t moving - it just wasn’t moving yet. Although with 61 seconds to full speed i think there would  have  been some movement after 5 seconds or so. So either i wasn’t patient enough or this wasn’t the problem. However, i would think reprogramming and/or resetting  to factory  settings would have corrected this, but it did not. So that’s weird.

i had time to work on it this afternoon. I gave it a shove - a few inches down the track and it kept going. Ran it around the layout for about 10 minutes….stoping, starting, accelerating, deceleration….powered down, re started etc, etc, etc., and  all was well. Set up a new consist ( i had cleared/killed/deleted the original one). The original consist was very closely speed-matched with each and every CV being the same. Reprogrammed the original values and this is no longer the case. so i rematched them. Very close, although oddly better in one direction than the other.

i have a love/hate relationship with DCC….

[peteski]

LokSound decoders have a forward and reverse trim for better speed matching in both directions.  CV66 and CV95.  Value if 128 is zero trim.  Values lower than 127 slow the model and higher speeds the model up.

[LIRR]

Thanks pete….i will look into that…

[LIRR]

Well….that was too easy. Definitely a problem. Grabbed my morning coffee and went to the trainroom, grabbed a few car for a run around the layout. Halfway, it just stopped moving. All the same symptoms.

damn. 

[Peachymike]

In my experience, decoders generally aren’t intermittent in operation, they either let the smoke out and do nothing, or will run uncontrollably. Basically when troubleshooting these sorts of problems the first step is to determine whether it’s electrical or mechanical. If there is no binding or tight spots then it’s the pickup, the decoder, connection to the motor or the motor itself. If you have a voltmeter you should be able to check for power to input on the decoder where the chassis contacts meet the board, where the output from the decoder to the motor, and at the motor itself. The last point  before you loose power is likely the source of your grief. If you have power all the way to the motor then the motor itself is the problem. Just go thru the system methodically, breaking it down to follow the flow of the current and you should able to nail it down. Intermittent contacts are the worst, they can be very unpredictable.
Mike

[LIRR]

Thanks
I didn’t think of that. I assumed the decoder was the problem, maybe motor…..