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Decoder contact problem

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PED
  • Member since
    April 2016
  • 571 posts
Posted by PED on Friday, May 25, 2018 12:36 PM

Glad to hear you got it working. I just added decoders to three Kato SDP40F and ran into same problem of loose decoder not making good electrical contact. I did not want to solder this setup so I wound up wedging some shrink wrap under the board to force it to make good contact.  Worked.

Paul D

N scale Washita and Santa Fe Railroad
Southern Oklahoma circa late 70's

  • Member since
    May 2018
  • 68 posts
Posted by Paul Schulze on Friday, May 25, 2018 11:24 AM

 

First off, I was incorrect about the fact that the lights were working.  They were not.  
 
I took the engine apart, put Kapton tape on places where the brass tabs might touch the frame and made sure that the tabs went through the decoder board slots.  Still would not work.
 
The solution, not necessarily pretty, was to place a piece of folded note card between the board and engine frame top.  Worked like a charm.  card material pushes the decoder board upward slightly against the frame slots and everything started working.  No soldering or extra wires. 
 
paul
  • Member since
    January 2014
  • From: Moneta, VA USA
  • 1,175 posts
Posted by gdelmoro on Friday, May 25, 2018 11:03 AM

rrinker

 

 
gdelmoro

Hi Guys, 

I’ve been following this post and have to ask, why would you want the decoder to contact the frame?  I always thought the objective was to isolate the decoder and motor from the frame.

 

 

 

 The OP is in N scale. Most N scale locos use a split frame for the power pickup, wheel wipers on each side are connected tot he frame. The frame connects to the factory circuit board which has the diodes and resistors for LED directional lighting, and that goes to the motor. A board replacement decoder needs to contact the frame for the power pickup, while keeping the motor leads, which are often brass tabs that fold up over a clip on the board, from touchting the frame. There are no wires, usually. Just a slot in each frame half that the factory board fits in and makes contact with. There are a few Bachmann HO locos built like this but it's not common for HO scale.

                             --Randy

 

Thanks for the education

Gary

  • Member since
    December 2015
  • From: Shenandoah Valley
  • 9,094 posts
Posted by BigDaddy on Monday, May 21, 2018 10:35 AM

Didn't think you could solder diecast with anything short of a torch

Henry

COB Potomac & Northern

Shenandoah Valley

  • Member since
    May 2018
  • 68 posts
Posted by Paul Schulze on Monday, May 21, 2018 10:23 AM

Paul, 

Just a note on soldering to the frame, I have some older locomotives that were fitted with Decoders having wires which were Soldered to the frame halves.

Because the frame halves are large and serve as a heat sink, I would imagine that it would take a very hot soldering iron.

Paul

PED
  • Member since
    April 2016
  • 571 posts
Posted by PED on Monday, May 21, 2018 8:56 AM

Paul Schulze

Paul,

Before the fix you described, did your lights work at all and/or were you able to read any CVs?  My lights work (forward and backward) on the Dash 8-40BW, but the motor will not turn at all.  Usually this seems to be attributed to poor contacts with the copper tabs from the motor; however, I can get good contact with the stock non-DCC light board and it runs on DC. 

I may have two bad decorders.  One is a DN163AO like you have and the other is a NCE N12AO.  Both decoders exhibit the same behavior.  Maybe they got fried somehow from intermittent current surges due to poor board-frame contact. 

Paul

 

The one with the light board ran fine (DC) and he one with the Lenz ran fine (DCC) before I modified them. The one that modified OK was no problem. Everything worked OK. The one that failed after the mod was real quirky due to the poor electrical contact. Lights would come on (minimal draw) but motor would not. Using DecoderPro, it would act like it was reading CV's but then it would come up with the message that DecoderPro could not coommunicate with the decoder. I inserted some toothpicks under the board to force it to fit tighter in the frame slot and all was well. Now I need to make a permanent fix to the problem child.

I am curious about the one that seems to work OK and why it worked OK in the same exact situation that they other failed to work. I am assuming that it managed to make enough electrical contact to work despite the loose fit. I suspect that somewhere down the road, it will quit on me and I will need to tighten the decoder board in it also.

Side note - back on my Atlas GP15-1, when it was acting up I decided to hard wire the board to the frame. Never have done that before and I discovered there is no good way to do that. Cannot solder to the frame metal. Solder will not stick to whatever type of metal it is. Only way would be to drill/tap for a screw to attach to and I did not want to mess with that so I just built up the contact pads with solder unit it fit right.

Paul D

N scale Washita and Santa Fe Railroad
Southern Oklahoma circa late 70's

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Monday, May 21, 2018 6:58 AM

gdelmoro

Hi Guys, 

I’ve been following this post and have to ask, why would you want the decoder to contact the frame?  I always thought the objective was to isolate the decoder and motor from the frame.

 

 The OP is in N scale. Most N scale locos use a split frame for the power pickup, wheel wipers on each side are connected tot he frame. The frame connects to the factory circuit board which has the diodes and resistors for LED directional lighting, and that goes to the motor. A board replacement decoder needs to contact the frame for the power pickup, while keeping the motor leads, which are often brass tabs that fold up over a clip on the board, from touchting the frame. There are no wires, usually. Just a slot in each frame half that the factory board fits in and makes contact with. There are a few Bachmann HO locos built like this but it's not common for HO scale.

                             --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    January 2014
  • From: Moneta, VA USA
  • 1,175 posts
Posted by gdelmoro on Monday, May 21, 2018 6:32 AM

Hi Guys, 

I’ve been following this post and have to ask, why would you want the decoder to contact the frame?  I always thought the objective was to isolate the decoder and motor from the frame.

Gary

  • Member since
    May 2018
  • 68 posts
Posted by Paul Schulze on Monday, May 21, 2018 12:38 AM

Paul,

Before the fix you described, did your lights work at all and/or were you able to read any CVs?  My lights work (forward and backward) on the Dash 8-40BW, but the motor will not turn at all.  Usually this seems to be attributed to poor contacts with the copper tabs from the motor; however, I can get good contact with the stock non-DCC light board and it runs on DC. 

I may have two bad decorders.  One is a DN163AO like you have and the other is a NCE N12AO.  Both decoders exhibit the same behavior.  Maybe they got fried somehow from intermittent current surges due to poor board-frame contact. 

Paul

PED
  • Member since
    April 2016
  • 571 posts
Posted by PED on Sunday, May 20, 2018 4:23 PM

My soldering iron is a Weller WES51. I can dial in any heat I want. I typically use a setting of 60 but I do not know what that means in watts. Never burned a board at that level.

I went ahead and installed a DN163A0 decoder in two Dash 8-40BW I had. One had a factory DCC board (Lenz?) already installed and the other still had the factory light board. One was a breeze - dropped in the decoder and it ran with no problem. The other had the same problem that I had with my GP15-1 - the slot for the decoder board was too wide and it would not run. I inserted some toothpicks under the board to hold it more tightly in place and it ran fine. 

On my GP15-1, I added some solder to the body contact pads (top side) then I filed them back down a bit until they made a snug fit in the body slots. Worked fine but was a PITA. Probably do the same to the decoder board in the Dash 8-40BW to make it work right.

Paul D

N scale Washita and Santa Fe Railroad
Southern Oklahoma circa late 70's

  • Member since
    May 2018
  • 68 posts
Posted by Paul Schulze on Sunday, May 20, 2018 9:27 AM

PED

I decided to hardwire the decoder in my Atlas GP15-1. Not what I wanted to do but I broke off a motor tab as I was installing and removing the decoder multiple times as I tried to figure out what was wrong. That left me with hard wire as my only option.

 

How did the decoder fit in the tab slots?  Do you know the wattage of the soldering iron you used?  I would be afraid of melting the board. 

PED
  • Member since
    April 2016
  • 571 posts
Posted by PED on Sunday, May 20, 2018 8:18 AM

I decided to hardwire the decoder in my Atlas GP15-1. Not what I wanted to do but I broke off a motor tab as I was installing and removing the decoder multiple times as I tried to figure out what was wrong. That left me with hard wire as my only option.

Paul D

N scale Washita and Santa Fe Railroad
Southern Oklahoma circa late 70's

  • Member since
    May 2018
  • 68 posts
Posted by Paul Schulze on Saturday, May 19, 2018 8:58 PM

PED

You may have fried the decoder moving stuff around. Do you have a second decoder to try?

I have the same engine and decoder sitting in my "to do" pile. I will install mine and see what happens.

 

just ordered a new one. The biggest problem is the replacement decoders seem to be too thin compared to the slits in the engine halives. 

 Somebody mentioned clips but I never saw any and I don’t seem to be able to find any information about them on the atlas website. 

PED
  • Member since
    April 2016
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Posted by PED on Saturday, May 19, 2018 7:00 PM

You may have fried the decoder moving stuff around. Do you have a second decoder to try?

I have the same engine and decoder sitting in my "to do" pile. I will install mine and see what happens.

Paul D

N scale Washita and Santa Fe Railroad
Southern Oklahoma circa late 70's

  • Member since
    May 2018
  • 68 posts
Posted by Paul Schulze on Saturday, May 19, 2018 3:41 PM

PED

Paul, I have a DN163A0 decoder that I had not installed yet so I checked it out. It is identical in style to the DN163A4 I had trouble installing in my Atlas GP15-1. I am sure you have the same proble I had.

If you look at the Atlas light board, it has 4 contact points where it picks up power from the frame. On mine, one side was soldered down but the clip wrapped around the board and was sprung up on the opposite side. This allows the stock light board to adjust to whatever the slot size is. My Digitrax decoder did not have that feature and I will bet yours does not either. Make the decoder board tight and I will bet it works.

 

I flattened som #20 copper wire with a hammer and made some small copper wedges for each terminal-shell contact and it still did not work.  I had good light control with no flicker and could R/W CVs just fine.  I'm wondering if I have a bad decoder.  BTW, I have an NCE N14AO which does the same thing.  I cannot remember its history but I gave it a try.

I currently have the original DC board in and it runs so I know the motor is fine.

PED
  • Member since
    April 2016
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Posted by PED on Saturday, May 19, 2018 1:01 PM

Paul, I have a DN163A0 decoder that I had not installed yet so I checked it out. It is identical in style to the DN163A4 I had trouble installing in my Atlas GP15-1. I am sure you have the same proble I had.

If you look at the Atlas light board, it has 4 contact points where it picks up power from the frame. On mine, one side was soldered down but the clip wrapped around the board and was sprung up on the opposite side. This allows the stock light board to adjust to whatever the slot size is. My Digitrax decoder did not have that feature and I will bet yours does not either. Make the decoder board tight and I will bet it works.

Paul D

N scale Washita and Santa Fe Railroad
Southern Oklahoma circa late 70's

PED
  • Member since
    April 2016
  • 571 posts
Posted by PED on Saturday, May 19, 2018 12:51 PM

I just got through fighting the same issue with an Atlas GP15-1. Tried two different decoders with the same results - nothing worked. As I was messing around with it, I noticed that the decoder was very loose in the mounting slots. Turns out that the decoder was made to work in multiple Atlas locos and they do not all fit the same. The mounting slots vary in thickness and my decoder was not making good contact with the frame (split frame) thus it was not picking up track power. I wedged some wooden toothpicks into the mounting slot along with the decoder so that the decoder was making solid contact with the frame and able to pick up track power.  That did the trick. Was able to program it OK and it ran fine. Now I need to figure out a permanent solution.

I should note that the Digitrax decoder instructions noted that the decoder had "maleable solder" on the contact pads so that you can file it down is the slots are too thin. Mine is the opposite situation and my slots are too wide. I may add a bit more solder to the pads to make them thicker.

Paul D

N scale Washita and Santa Fe Railroad
Southern Oklahoma circa late 70's

  • Member since
    May 2018
  • 68 posts
Posted by Paul Schulze on Saturday, May 19, 2018 12:40 PM

 Are there other decoders out there that would work and have the slots for the boader contacts? I have run across a number of articles dealing with motor contact problems with the decoders. 

  • Member since
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Posted by BNSF UP and others modeler on Saturday, May 19, 2018 12:35 PM

Check to make sure that your motor wires and/or your positive and negative power wires are where they should be. Also, it could just be digitrax. Their decoders are low on my favorites list. 

I'm beginning to realize that Windows 10 and sound decoders have a lot in common. There are so many things you have to change in order to get them to work the way you want.

  • Member since
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Decoder contact problem
Posted by Paul Schulze on Saturday, May 19, 2018 12:08 PM

I bought an atlas  Dash 4-80BW and a Digitrax DN163AO decoder.   I tested the Loco and it ran fine on a test track with just a DC power supply. I then put the DN163AO decoder in and the lights worked fine but the loco would not move on the DCC track. I put the original electronic board back into the loco and the loco ran fine on DCC address 00 (but only at very low speed). I then put the  DN163AO back in, and this time I put the tabs from the motor through the little slots as I did not see them the first time. The loco is essentially back to where it was before, that is, the lights work (some of the time ) and the loco won’t move. I am at a loss as what to do. I could solder the tabs to the board but I am a little leery of doing that. The decoder board just seems to be losing contact in one or more places and is definitely loose in the frame halves. Any suggestions would really be helpful  

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