Author Topic: DCC Grrrr..... (new info)  (Read 415 times)

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mecgp7

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DCC Grrrr..... (new info)
« on: May 03, 2024, 03:26:39 PM »
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I absolutely hate DCC as I have had nothing but trouble with it. I have a Digitrax DCS 50 just to test locos that I purchased that happen to have decoders. Before Peteski jumps in here and tells me for the 100th time that I need to learn more about DCC, I will add that I can read and have gone through multiple instructions on using DCC. I can read addresses and I can program addresses. I cannot decipher all the issues that I have (railroad related, not mental). I have locos that I can program the address, but can't make them run. I have a handfull of DCC locos that light up, but that is all I can get out of them.
Near as I can tell, most of the decoders are Atlas factory models. I have a few locos with TCS and have some issues with them.
I read a great deal about the "quarter" trick and even made my own resistor soldered to the programming track as explained by those in the know.
Is the decoder no good if I can program an address? How does one factory reset multiple decoders from different manufacturers with the digital system that I have?
Many thanks in advance.
« Last Edit: May 03, 2024, 04:58:10 PM by mecgp7 »

Mike C

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Re: DCC Grrrr.....
« Reply #1 on: May 03, 2024, 03:34:39 PM »
+3
 Atlass locos have a known problem with the decoders . Simply the motor contacts from the decoder need to be soldered to the motor . I know that they are supposed to work without doing this but connectivity without soldering is iffy at best .    Mike

jagged ben

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Re: DCC Grrrr.....
« Reply #2 on: May 03, 2024, 03:47:44 PM »
+1
Are these factory installed decoders or did you install them?

I would suspect that at least some of your issues, if not most of them, are due to the motor leads not making contact with the decoder, or making contact with the frames.  This is a frequent problem with Atlas' mechanisms and DCC.  You really have to be very careful when installing decoders that the motor leads stay just so, in order to make contact.  If they get bent or sometimes shifted backward or forward then there's no contact and the motor gets no power.   Some guys solder the motor leads to the decoder [as mike posted while I was typing].  Another thing is to wrap kapton tape around the frames in the area around the motor leads; otherwise the motor leads can contact the frame and bad things can happen, including burning out the motor drive chips on the decoder.  Your locos that light up but don't move, assuming you can control the lights with the address, likely have one of these things going on.

If you can read back and verify an address you programmed but not turn the lights on and off (function zero, change direction back and forth), then the decoder is likely bad, or needs a reset.  If the lights work fine but the motor doesn't turn, see above.

Almost every decoder can be reset by writing a value of 8 to CV 8.


mecgp7

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Re: DCC Grrrr.....
« Reply #3 on: May 03, 2024, 03:49:14 PM »
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Thank you guys. If the issue were connectivity then the locos wouldn't run on DC correct? I have no doubt that some of these decoders are junk, but I don't understand how I can still modify the addresses etc.
Could someone walk me through a factory reset on a Digitrax DCS 50 system?
I truly appreciate any and all help.
« Last Edit: May 03, 2024, 03:57:11 PM by mecgp7 »

mecgp7

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Re: DCC Grrrr..... (new info)
« Reply #4 on: May 03, 2024, 05:04:57 PM »
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I just discovered that if I put a particular loco with decoder on my DCC test track (not the program track), it will take off running when the Digitrax direction is on "brake" and the throttle is at "Stop".  Not sure how to explain that?

nickelplate759

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Re: DCC Grrrr..... (new info)
« Reply #5 on: May 03, 2024, 05:09:16 PM »
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Does the runaway by any chance have a TCS CN or CN-GP board (often used in Atlas/Kato diesels, and early Atlas China RS3, RS11, GP7, G9, and at the first metal-frame version of the Life Like GP18.)?  If so, that's often because of poor contact between one the two boards and the chassis.
George
NKPH&TS #3628

I'm sorry Dave, I'm afraid I can't do that.

mecgp7

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Re: DCC Grrrr..... (new info)
« Reply #6 on: May 03, 2024, 05:21:00 PM »
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It is a factory Atlas GP38 that runs when supposedly the Digitrax system is on brake and stop.
I just don't get it!

jagged ben

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Re: DCC Grrrr..... (new info)
« Reply #7 on: May 04, 2024, 02:41:39 AM »
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That sort of thing can definitely be a sign that the motor isn't isolated from th frame and pickups.

PRRS

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Re: DCC Grrrr..... (new info)
« Reply #8 on: May 04, 2024, 07:02:27 AM »
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Your decoder is in danger of shorting out.  It's the motor contacts...the motor isn't isolated.  You need to make sure that the motor contacts do not touch the frame in any way shape or form.  This means adding tape around the frame where the contacts are...or...if in a difficult area...you can paint the frame where the contacts are.  I use an enamel paint pen for this.  Still...the tape is better...like Kapton tape.

I had the exact same problem you describe with my AZL Z Scale engines.  The motor contacts are very close to the frame depending on the age of the loco...some are worse than others.  I've had to bend in the contacts from the frame to eliminate this problem and then add tape for insulation from the frame.

Burned a hole in the top of the plastic on one GP7 engine when the engine took off...stopped...and the decoder just about ignited.  The diode was glowing red!

So yes...I wish manufacturers would be a little less lazy when it came to these designs/manufacturing practices.  AZL is improving with their latest offerings.