Hard Wire non-Next18 Decoder in Dapol 00 Steam Locomotive

[Right Away]

I’m curious as to how feasible it would be to hard wire a non-Next18 decoder in a Dapol 00 steam locomotive.

I have hard wired many engines over the years but have not as yet had any dealings with Dapol’s smokebox located, slide in Next18 system.

The main concern would seem to be that of gaining access to enough of the circuit board wiring to effect soldering; online user guides do not mention body removal.

Why, some will ask, would anyone wish to circumvent a neat, foolproof decoder system?

I have a certain mistrust where inaccessible components simply “click” together (bad/loose contacts), regardless of how convenient they may initially appear.

For this reason, it can be extremely helpful to have a “work around” at hand in the event of any problems before acquiring one of these models.

 

[Suzie]

Simple answer:- There will generally be four wires going to the Next-18 socket, and you can just splice these on to your decoder wires or solder directly to the next-18 decoder (many small decoders are just the Next-18 decoder with wires attached instead of the plug).

 

Issues that will occur:-

1.  Next-18 (and PluX) sockets include a defined space that the decoder will fit in to. Using a non-standard sized decoder will most likely mean that you will have to clear some space somewhere in the loco for the decoder and wires, especially for a sound decoder with a speaker and stay alive. Next-18s socket has room for a sound decoder.
2. Next-18 (and PluX, and MTC-21) use very reliable connectors that are likely to make a connection when plugged in that will outlast most amateur soldered connections (especially if lead is involved).
3. It is an awful lot of work to no advantage, especially when Next-18 (and PluX) decoders of the finest quality can be had for £25.

The Next-18 socket is nothing like the somewhat less reliable NEM651 6-pin or NEM652 8-pin connectors which you might consider replacing with a hard wired connection for a good reason.

[34theletterbetweenB&D]

On 15/12/2023 at 19:57, Right Away said:

The main concern would seem to be that of gaining access to enough of the circuit board wiring to effect soldering; online user guides do not mention body removal.

I have a slightly different take on this. Most of the electrical trouble I have seen on RTR OO hasn't been on the decoder socket but rather on the quality of the wiring connections and wire paths from pick ups to the socket and from socket to motor, causing continuity failures.

 

As such where there is an electrical continuity problem, my usual approach is to remove the existing wiring and socket and to solder on the decoder wires to pick up wipers and motor terminals, arranging the wiring so it will not be trapped between body and mechanism. 

 

As for body removal, models are assembled kits and will surely come apart, but I have zero experience of current Dapol steam loco construction, and hope someone can enlighten us.

[34theletterbetweenB&D]

There is a fair amount of discussion concerning getting the Dapol 'D' class 4-4-0 (Rails of Sheffield commission) apart, which may supply some hints. Randomly dropped into the thread at p45 where there was some likely looking information, but no time to survey it all at present.

 

[Harlequin]

I don't know whether all Dapol's smokebox door access steam locos are the same but FWIW here's the inside of the Large Prairie, during installation of a bigger speaker:

 

The body came off in the traditional way (2 or 3 screws underneath). Ignore the pink wires and the big speaker temporarily mounted on the front of the chassis for testing.

 

You can see the decoder plugged into the carrier board and the carrier board plugged into the large black socket on the "motherboard".

The motherboard is where all the permanent wiring is fixed to.

The carrier board (and decoder or blanking plate) is what you pull out and push back in through the smokebox door when the body is on. They must be removed to get the body off.

 

It would be very easy to remove the motherboard (it's just located in a slot) and wire a decoder directly to the pickup wires and motor wires BUT you'd have to find a way to get the body back on with the hard-wired decoder in place. If the decoder is very small that might be easy. If it's big then you'd probably have to leave a lot of slack in the wires, thread the decoder through the smokebox as the body went on and then bundle the wires up and push them and the decoder back in.

 

Edited December 20, 2023 by Harlequin

[Right Away]

21 hours ago, Harlequin said:

I don't know whether all Dapol's smokebox door access steam locos are the same but FWIW here's the inside of the Large Prairie, during installation of a bigger speaker:

 

The body came off in the traditional way (2 or 3 screws underneath). Ignore the pink wires and the big speaker temporarily mounted on the front of the chassis for testing.

 

You can see the decoder plugged into the carrier board and the carrier board plugged into the large black socket on the "motherboard".

The motherboard is where all the permanent wiring is fixed to.

The carrier board (and decoder or blanking plate) is what you pull out and push back in through the smokebox door when the body is on. They must be removed to get the body off.

 

It would be very easy to remove the motherboard (it's just located in a slot) and wire a decoder directly to the pickup wires and motor wires BUT you'd have to find a way to get the body back on with the hard-wired decoder in place. If the decoder is very small that might be easy. If it's big then you'd probably have to leave a lot of slack in the wires, thread the decoder through the smokebox as the body went on and then bundle the wires up and push them and the decoder back in.

 

Excellent Phil. thanks very much. I’d wager the 4-4-0 would be very similar, once inside.

[34theletterbetweenB&D]

23 hours ago, Harlequin said:

...BUT you'd have to find a way to get the body back on with the hard-wired decoder in place. If the decoder is very small that might be easy. If it's big then you'd probably have to leave a lot of slack in the wires, thread the decoder through the smokebox as the body went on and then bundle the wires up and push them and the decoder back in...

Ah, the fine art of installing wired decoders, so familiar to those of us that started out in DCC with mechanisms constructed before thoughts of decoders.

 

Top tip: see all those wires that aren't red, orange, grey and black? Snip them off, makes life much easier.

 

Also it can be helpful to create a decoder 'compartment', nothing more than a cemented in piece of plasticard will do, so the decoder cannot 'wander about' once the body is back in position.

[KingEdwardII]

To me, this all looks like a pile of hard work for very little gain. It seems like a solution looking for a problem.

 

I have a Dapol Manor - and I got a Next 18 decoder and slid it into place using Dapol's mechanism. Simple and straightforward...

 

Yours, Mike.

[34theletterbetweenB&D]

2 hours ago, KingEdwardII said:

To me, this all looks like a pile of hard work for very little gain. It seems like a solution looking for a problem...

It's a simple solution, handy to have in the 'toolbox' for those occasions when there is a electrical continuity fault, once a model is out of warranty. Come to me low price s/h non-runners...

[peterm1]

On 20/12/2023 at 20:33, 34theletterbetweenB&D said:

There is a fair amount of discussion concerning getting the Dapol 'D' class 4-4-0 (Rails of Sheffield commission) apart, which may supply some hints. Randomly dropped into the thread at p45 where there was some likely looking information, but no time to survey it all at present.

 

Aah, the D class. I bought one from RoS and it went to and fro from Australia and England, because Ros wouldn't take my word that there was a fault only apparent on DCC. In the end they must have re read my email/s and checked the tender wiring which was faulty. They sent me a new tender and the fault was gone, but I still had a Zimo MX658N18 decoder burnt out. I contacted Dapol and ended up getting half the cost of said decoder sent to me. Zimo repaired the decoder at my expense, so I now have one spare, that I'll probably use one day. Luckily for me, RoS paid all postage costs.

[Right Away]

5 hours ago, KingEdwardII said:

To me, this all looks like a pile of hard work for very little gain. It seems like a solution looking for a problem.

 

I have a Dapol Manor - and I got a Next 18 decoder and slid it into place using Dapol's mechanism. Simple and straightforward...

 

Yours, Mike.

In the original posting it will be remembered that information was sought regarding access to the innards of the particular Dapol engines as little has been available elsewhere.

Never a pessimist forever looking for problems, but being capable of effecting repairs SHOULD  they arise, it is assistance of the kind that Harlequin (above) has provided that is very much appreciated.

Of course, it is hoped that this information will never be required on a forthcoming purchase of a Dapol steam locomotive - but one can never be certain.

 

[Butler Henderson]

The pull out board is an added potential weakness especially if the connecting wires are soldered to the mimimal extent that often crops ups these days . Have three such locos and one has had to be hard wired, Not sure why their would be a need to hard wire a Next 18 as any lead fitted decoder (8 pin for example) can be used.

Edited December 23, 2023 by Butler Henderson

[Right Away]

15 hours ago, Butler Henderson said:

……, Not sure why their would be a need to hard wire a Next 18 as any lead fitted decoder (8 pin for example) can be used.

 

The original query specifically relates to the feasibility of hard-wiring a non-Next18 decoder, with particular emphasis on accessibility.

 

The engines to which I have had recourse in the past to hard wire have been equipped with either Lenz 10231-02 or Zimo MX600R decoders, (with, of course, the 8 pin plugs removed). It would be to similar measures that I would look, should I have the misfortune to effect a repair on a Dapol Next 18 equipped loco.

 

Thank you for mentioning your experiences as it does go some way to vindicate my initial scepticism. 

[Right Away]

 

As a follow up and for those for whom it might be of interest, I’ve attached some piccies of the Dapol D1 “exposed” as it were, prior to the hard wiring of a Zimo MX600R decoder.

 

Firstly, remove the decoder interface plug-in board before removal of the locomotive’s body.

Body is secured with just two screws - see photo; the body coming away cleanly.

As always, it is essential to identify all wiring with a meter before embarking on disconnection of the Next18 interface gear. 

Note: On my example, the top and bottom motor feed wire colours were reversed (not in itself an issue as if this were missed it can be corrected by a change of CV29, bit 0=1). 

Also, the orange motor wire was very closer in hue to red, so be sure to tag this and the black motor wire with a tiny strip of tape for identification.

The firebox LED wires are Red, Black and Yellow, again be wary of the first two.