Caution when fitting decoders to so called Ready locos

Discussion in 'DCC Control' started by Jim Freight, Sep 16, 2019.

  1. Jim Freight

    Jim Freight Full Member

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    I have fitted DCC decoders to a fair number of so called ready locomotives over the last few years and a word of caution to anyone contemplating fitting one themselves.

    Initially DC test and run in the loco if required.

    Absolutely always test on the programming track after fitting a decoder and if the programming tool/software says there is short cct (or 'short cut' on my Lenz system) believe it otherwise smoke release from a decoder is likely when placed on the running track.

    It appears to me that locomotives factory assembled with blanking plates/plugs fitted are not thoroughly tested, a number of faults can be hidden, here is some I have found, initially by smoking a decoder or two.

    1) crushed damaged wires - e.g. Heljan railbus
    2) wires swapped at connector - e.g. Red/Orange or Black/Grey- e.g. Heljan railbus
    3) chassis wired with brown wires, motor wired red and black, the red and black then being wired in the correct position at the decoder socket for track power. So track power and motor leads swapped at the socket. e.g Model Rail / Kernow Sentinel
    4) pair of tender to loco 2 pin connectors swapped at tender, thus swapping motor and track wires at tender. Wires too short to swap connectors over so fixed by soldering within the tender e.g. Bachmann Ivatt 2MT.
    5) a manufacturers own decoder needs tape to prevent shorting against metal cradle lugs e.g. Hornby Peckett.
    6) light connections swapped at decoder socket e.g. Heljan Hunslet 05

    The general standard of the hand soldering is very poor across many makes of models and some decoder manufacturers.

    We pay a lot a money for these models and fixing them is time consuming for those who can do it and expensive for those who cannot.

    If any manufacturers are reading this please help us and we will buy more!
     
    Last edited: Sep 16, 2019
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  2. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    Thanks for the heads up on the above points. Always good to know.

    Toto
     
  3. Andy_Sollis

    Andy_Sollis Full Member

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    Only yesterday i was hard wiring a Hornby loco. Loco feed and tender feeds... instructions say wire red to red and black to black..

    Not sure who wired this originally.

    34F294D6-EA27-4961-A491-663C18ABDEA2.jpeg
     
  4. Jim Freight

    Jim Freight Full Member

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    Wrong place, how to delete?
     
  5. Jim Freight

    Jim Freight Full Member

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    The grey bit is probably a ferrite inductor/choke all this installed by the manufacturer, I've seen a few, used in conjunction with the orange capacitor. Jim
     
    Last edited: Sep 17, 2019
  6. Jim Freight

    Jim Freight Full Member

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    I tend to remove this clutter when hard wiring.
     
  7. Keith M

    Keith M Staff Member Moderator

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    Capacitors should be removed when DCC converting as a general rule, same with chokes/inductors as they can affect the correct operation of the decoder. Hornby are responsible for a number of known "Cock-ups" with regard to correct marking of the No 1 pin on a 'DCC Ready' loco, also incorrect socket wiring resulting in the dreaded white smoke from the decoder on several models. Unfortunately, since it's all "Made in China", it seems that quality control is not necessarily one of the factories strong points. I never use either Hornby or Bachmann decoders, general advice (not just mine!) is not to use decoders 'manufactured' by model manufacturers, stick to the known and trusted brands from electronics specialists, horses for courses I guess. Some of the smaller 'DCC Ready' loco's don't have enough space for sound decoders, never mind the speaker, so it's sometimes necessary to remove the 8 pin socket and some of the chassis metalwork, not normally a problem as it's usually soft zinc alloy, then hard wire in. As yet, I've not come across any of these "Plux18" or the 22 pin decoders, but as time goes on, I reckon 6 and 8 pin decoders will either be phased out or relegated to very simple loco applications as there just aren't enough available connections for the functions being introduced as standard nowadays, and why not, as we're paying enough for them. I am not personally a fan of ESU sound decoders, having had 2 consecutive ones fail before even refitting the loco body, so for sound applications I always go for Zimo decoders, with sound files from John Gymer at YouChoos, who I have no connection with except as a satisfied customer. A further 'Put-off', at least for me, is that ESU insist on supplying a speaker with each decoder, fine if it happens to fit, but an unnecessary expense if it doesn't, as you then have to pay again for a suitable speaker! These are my personal observations from my 6 years or so of experience with DCC, and may not represent the experience of others, I can only 'Speak as I find'.
    Keith.
     
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  8. Jim Freight

    Jim Freight Full Member

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    Hi Keith

    I certainly agree with the items I have shown as an edited quote above, for some locos particularly Hornby it is easier to fit decoders by hardwiring, even a non-sound decoder in a 2-6-0 or even 9F by removing the socket PCB which combined with a direct fit decoder takes up far too much height. IMO the only decoders that can be easily fitted are the manufacturers own offerings and the less said about them the better. I get the impression pre-owned locos with or without manufacturer factory fitted decoders are becoming the same price. I have yet to find one worth keeping.

    The other features/aggro you mention I have not experienced due to my basic decoder requirements.

    My decoder requirements are simple and generally available on any non-loco manuf's decoders these days, BEMF for low speed, min,mid and max speed settings, turn off analogue mode, acceleration/deceleration delay and occasionally F0 for auto head and tail lights on some diesels.

    I will always remove inductors and capacitors from hardwired installations as I too believe it is unnecessary due to the decoder being between the noise source (the motor) and the rails. I will also remove them if a socketed fit proves unreliable.

    The Bulleid 10203 loco comes complete with a speaker, don't need, bracket fouls the body pillars (another story posted elsewhere), oh well extra ballast!.

    Jim
     
    Last edited: Sep 17, 2019
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  9. Andy_Sollis

    Andy_Sollis Full Member

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    Nope, the grey bit is just a small bit of plastic that keeps the wires apart.

    And hornbys own website says retain the capacitor

    https://www.hornby.com/uk-en/r2675-railroad-flying-scotsman-decoder-installation

    Although the casting has a fitment for a DCC 8 pin socket (not factory fitted) it’s held by one screw. That came out and left a little more room for the sound decoder.
     
  10. Jim Freight

    Jim Freight Full Member

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    Well I have noticed that wires entering it are not necessarily insulated, think I will cut one in half to examine closer :scratchchin:

    Ferrite chokes can have the wires passed through them as opposed to inductors which are wired in series with the motor and attached to both motor wires..

    Keeping those parts is down to personal theories, and in this case it may be necessary for Hornby's decoder, if it works leave it, if there are problems, well ....
     
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  11. Graeme

    Graeme Full Member

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    Well this has now made me re-think about converting my Bachmann Spectrum locos to DCC.
    The ones I have looked at appear to have an 8 pin socket.
    I am building a small HO layout and have DCC controllers that I intended to use
    I was just going to post a request for advice on which decoders to use when I saw this, now I am not sure whether to proceed or not.
    Will still ask for advice though so I can weigh the pros and cons.
     
  12. Jim Freight

    Jim Freight Full Member

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    :hismiley:, don't be put off, I think it was still worth the effort :hammer: , honest :thumbs:
     
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  13. Andy_Sollis

    Andy_Sollis Full Member

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    Out of the thirty odd locos I’ve chipped, I’ve only ever fried 2. One was operator error and the other was a few days ago when the loco had seized up and drew too much current and that was that.

    Good excuse to replace it with a Hornby TTS decoder.
     
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  14. Graeme

    Graeme Full Member

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    OK DCC is back on the agenda.
    Now to put the cat amongst the pigeons, what decoders should I use?
    I have NCE controllers, both the "Twin" and the "Powercab" so which one to use is another decision, I'll just have to read up on them unless somebody has experience with them and could give me an idea.
     
  15. Andy_Sollis

    Andy_Sollis Full Member

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    You don’t suit a decoder to a controller, you suit the decoder to the loco - based on the amp draw of the loco motor stalled, and how many functions you may or may not need. Or sound.
     
  16. paul_l

    paul_l Staff Member Administrator

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    For the NCE PowerCab, a worthwhile extra is the AutoSwitch :- "Adds a separate program track to Power Cab system. Prevents accidental programming of ALL locos on your track when using Program Track mode. Automatically disconnects your main line when in Program Track mode but does not affect Program on Main. Compatible with all DCC systems."

    Before fitting a sound decoder, I fit a cheapo decoder (aka Hornby, Hattons, Laisdcc etc), if all is ok then I fit the dearer decoder.
    Fortunately, I haven't had a badly wired socket - maybe the majority of the loco's I've done were not DCC ready, so my fault completely if I blow something :whatever:

    I have occations were following a short or some other incident, has resulted in a decoder loosing its settings including its ID. Apart from being a Pain, if you use JMRI DecoderPro (if your system has a computer interface I cannot reccommend Decoder Pro highly enough), it is a simple matter of re-writing the settings back into the decoder. For Bachmann DMU's that use a decoder per carriage :(, I have programmed up the motor bogie, saved the config, then used the same decoder in each carriage, and written the motor bogie settings to each remaining carriage.

    A continuity tester is also a simple way of "belling out"

    [​IMG]

    With the plug removed, and the meter / continuity tester Pin 4 & 8 should be connected to the wheels, and 1 & 5 to the motor terminals, if these do not bell out correctly the you have a problem.
    Also if Pin 1 is not obvious, and you insert the plug the wrong way round, the only effect is the loco runs in reverse, and the accessory lights don't work, no damge will occur, just swap the plug round.

    Paul
     
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  17. Graeme

    Graeme Full Member

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    Thank you for the diagram a picture speaks a thousand word for me.
     
  18. Graeme

    Graeme Full Member

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    Back in April this thread was posted; https://platform1mrc.com/p1mrc/index.php?threads/dcc-chips-for-locos.4068/ in it there were recommendations for LaisDCC decoders which would most likely suit my purpose.

    Does any Australian contributors know where I could source these decoders locally, without me having to go overseas or alternatively any source for them for O/S contributors if not available in Aust?
     
  19. Keith M

    Keith M Staff Member Moderator

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    I believe SMR Chris (one of the Mods) stocks and recommends these decoders in Aus (As do I, having fitted around 50 to my 'stable' of loco's. At present, it seems they do not as yet have any DCC sound decoders, but I live in hope! UK prices for 6, 8 and 21 pin decoders is currently around £10 each via Ebay from at least 3 sellers, so cheap enough. I am presently looking at fitting sound to a 90 year old friends Hornby R3333 Adams Radial, these loco's are known for having a wiring fault from new which blows decoders. It appears that the lead bogie (which has it's own pickups) is incorrectly wired to inner connections on the 8 pin socket, the driving wheels being correctly wired to outer pins. Whilst the loco works fine on DC, plugging in a DCC decoder instantly destroys it, since track voltage is applied to the decoder output, not the first time Hornby (or their Chinese manufacturers) have cocked up the wiring connections! Says little for their Quality Control!
    Keith.
     
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  20. Bernie

    Bernie Full Member

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    Being new to the hobby and DCC I was shocked by the lack of DCC capability of a DCC ready locomotive.

    I have 2 Hornby DCC ready locos, and nothing on the box or documentation says what connection is required. I had to pull them both apart to find they were 8 pin sockets. Although both were 4-6-0 tenders, Hornby Grange and Standard 4 they have a completely different internal design. Grange has the socket in the loco and the std 4 in the tender. The std 4 had tiny screws hidden down very long pillars, that were there for no reason other than to make it difficult. Very delicate bits just fell off the grange when separating chassis from body. Fortunately both have loads of room for the decoders and wire.

    A Bachman std 4 tank has DCC 8 pin on the box, but the instructions say if I fit a decoder it voids the warranty. It has 2 tiny screws at the back that my #0 Philips head would not fit, and one screw in each of the tanks deep behind the valve gear, blu tack to the rescue here. The socket marked the '8' pin. I had to find the socket pin-out online to identify how the chip was inserted. And this is not easy, some definitions described the wire colour (red), others described the wire function (right track) others the pin numbers, so took ages to locate which one was which. DCC ready does not mean easy.

    A DJ Kernow 1361 class 0-6-0 tank is simple, pull off the magnetic smoke box door, pull out the plug and insert the 6 pin chip. Push it all back in. And that is a very tiny locomotive, much smaller than a jinty.

    The next easiest loco I have to convert is a DAPOL 0-4-2 tank. Just one screw down the funnel, cut the motor wires that have extra length twisted into them and connect the decoder which sits nicely in the bunker. Not DCC ready but easy.

    Decoder choice, I cant tell if it is decoder or loco, but:
    • the DCC fitted hornby Jinty makes a buzzing racket when starting and does not move till about speed 4 or 5 out of 28. It did improve being less erratic when I pulled out the socket and cleaned the pins.
    • the DCC concepts basic decoder works wonderfully in the hornby grange, speed 1 works perfectly and silently.
    • digitrax works well in the backmann, nothing remarkable but this was very cheap.
    TIP: have loco crew ready to insert, these things are a pain to open up and close again, with crew ready only do it once.
     
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