Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Things to check when installing a decoder.

2753 views
10 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    January 2007
  • From: Eastern Shore Virginia
  • 3,290 posts
Posted by gandydancer19 on Wednesday, July 18, 2012 5:27 PM

 

I no longer trust manufacturers to get it right when they have a socket that all you have to do is plug in a decoder.

I specifically recall an N scale Bachmann that had a separate light board that wasn't isolated from the frame. I have had a couple of other bad experiences with other manufacturers as well.

So on all conversions now, I remove any “light boards” or “decoder plug-in boards” and either hard wire the decoder in, or find a direct replacement decoder that replaces the “light board”. The other option is to purchase new locos that have DCC installed, and I have also done that with some sound locos.

Elmer.

The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.

(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.

  • Member since
    January 2008
  • 595 posts
Posted by mreagant on Wednesday, July 18, 2012 4:17 PM

rrinker

 To just plug in a decoder on this loco, there are multiple traces on the pc board that need to be cut COMPLETELY through - a trianguler needle file works bettr to make sure the connection is severed, but copper traces can be cut with a standard #2 knife. Miss one, or have it not completely cut (test with a meter in continuity mode) and it will almost certainly fry the decoder.

                  --Randy

 

Uh? OK.  I took a close look at this board and there are no x's suggesting places to cut the printed circuit.  There was also no instruction to do anything other than plug in the decoder.  I know this P2K is at least 6 or more years old so maybe a different board?  Any ideas?

Mike

  • Member since
    June 2006
  • From: Maryville IL
  • 9,577 posts
Posted by cudaken on Wednesday, July 18, 2012 4:13 PM

 Randy, my circuit board has no areas that need to be cut, well there is nothing marked on it that is.

 Mike, I ran mine for years by just plugin in the decoder. First decoder problem (some time ago) was do to a defective motor. Now this last problem that spawn this question is still a mystery, but I am replacing the board to be on the safe side.

 Besides, it is not that hard.

 Ken

I hate Rust

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Wednesday, July 18, 2012 12:56 PM

 To just plug in a decoder on this loco, there are multiple traces on the pc board that need to be cut COMPLETELY through - a trianguler needle file works bettr to make sure the connection is severed, but copper traces can be cut with a standard #2 knife. Miss one, or have it not completely cut (test with a meter in continuity mode) and it will almost certainly fry the decoder.

                  --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 2008
  • 595 posts
Posted by mreagant on Wednesday, July 18, 2012 10:35 AM

OK, don't mean to jump into the middle of this discussion with an obvious question, but I read the previous thread and this one and I'm confused.  I was just about to install a DH163PH into a P2K SD7.  I've had the loco for at least 6  or 7 years  Looks to be a simple plug n' play deal since the decoder comes with a 9 to 8 pin harness and the SD7 is "DCC" ready" with NMRA plug receptical on the board.

Should I proceed?  I've never had trouble with these  plug-in decoders either on Proto locomotives of a couple of other brands I've used them on.

Mike

  • Member since
    August 2011
  • 805 posts
Posted by narrow gauge nuclear on Wednesday, July 18, 2012 9:09 AM

Re: one of the original questions......Putting an LED in backwards will not hurt a decoder or the LED at all.  No current will flow, (the diode is simply reverse biased).  The LED just will not turn on, that is all.

Richard

If I can't fix it, I can fix it so it can't be fixed

  • Member since
    June 2006
  • From: Maryville IL
  • 9,577 posts
Posted by cudaken on Wednesday, July 18, 2012 8:04 AM

 Thanks for the answers folks.

 Ken

I hate Rust

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Tuesday, July 17, 2012 5:45 PM

 I did one P2K SD7, the circuit board has several palces marked with X's to cut when instralling a decoder. I spent an hour or so goign over the circuit traces and drawing it out, and then cutting hwere the X's were, and it made no real sense why it was wired as it was. So I solved the problem and removed the circuit board completely. There are wires from each truck pickup, and wires fromthe motor, it was already isolated, so I just connected a wired decoder, connecting the appropriate wires to the decoder elads, and added LEDs with 1K resistors to the front and rear headlight wires. Simple and it worked.

 Guess it's pretty obvious by now - I HATE "DCC Ready" since more often than not, it's not. Hard wire, almost always. Haven't smoked a single decoder ever. I don;t use decoders with wires soldered to them, I use ones with 9 pin connectors and a wiring harness, so the decoder can be swapped, or even replaced with a 9 pin dummy plug to make the loco DC again.

                  --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
    June 2006
  • From: Maryville IL
  • 9,577 posts
Posted by cudaken on Tuesday, July 17, 2012 5:42 PM

 Stix's, guess you did not look at the link. Decoder Pro read the decoder with no problem.

 Ken

I hate Rust

  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 13,892 posts
Posted by wjstix on Tuesday, July 17, 2012 5:12 PM

I don't think the P2K engines have any trouble as far as the motor not being isolated?? Only engines I've had to do that to were a few old Mantua steam engines, Athearn bluebox diesels, and the old (Roco) Walthers FM switcher. Anything made in the last 10-15 years is probably OK.

Main thing with decoder install is to put the engine on the programming track first!! Try to read back a CV. If it shows up OK, there are no shorts. If it doesn't show up, there may be a problem - but the power on the programming track is low enough that a short circuit won't fry the decoder.

Stix
  • Member since
    June 2006
  • From: Maryville IL
  • 9,577 posts
Things to check when installing a decoder.
Posted by cudaken on Tuesday, July 17, 2012 4:15 PM

 Going to give the PK 2 SD 7 another shoot.

See this post for more details.  http://cs.trains.com/TRCCS/forums/t/208090.aspx

 This time I am going to hard wire the decoder and looking for idea's of what to check before I but it on the mainline.

 Here's what I have came up with.

 1 Double check and add tape to frame to make sure the motor is not grounded. It is a DCC ready engine and ran for years before the old motor died.

 2 Check to make sure wheels sets are in gauge. That way the axle's ends don't touch and cause a short.

 3 Shrink wrap all solder joints.

 In other idea's?

 If you looked at the above link, replacement motor is in good shape as far as Amps it is pulling.

 Hum, If I wired the LED wrong, could it have burned on the decoder motor drive?

 Thank You for the coming ideas!

 Ken

I hate Rust

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!