Fitting lights with a 21 pin decoder and other tedious decoder questions

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Michaelaface
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Fitting lights with a 21 pin decoder and other tedious decoder questions

Postby Michaelaface » Mon Jun 01, 2020 3:15 am

I feel like I'm missing something really obvious here, but if I wanted to fit lights to a steam loco with a 21 pin decoder where do I solder the wires? directly to the pin connections on the locos pcb board or what? there doesn't appear to be any clear solder tabs on said board for lights/aux connections, just motor, pickups and stay alive, there's no documentation on the wiring with the loco, and I can't find anything on the Bachmann website

I have had a search looking for the answer for this, and I either can't find an answer or I'm searching for the wrong thing, so rather than potentially making a mess thought I'd ask here first

the loco in question is a Bachmann J11
and the lighting is the DCC concepts loco lamps and an LED for firebox flicker
Last edited by Michaelaface on Tue Jun 16, 2020 1:29 am, edited 1 time in total.

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Ironduke
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Ironduke » Mon Jun 01, 2020 6:20 am

Regards
Rob

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SRman
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby SRman » Mon Jun 01, 2020 8:47 am

You can solder to the decoder; most do have solder pads on them for this. However, I am too timid to do this as too much heat could destroy the decoder. In the absence of solder pads on the lcomotive PCB, I solder to the base of the pins. This also allows the use of different decoders if it becomes necessary to swap them later.

It still takes a steady hand and good eyes to do the soldering but it does allow for separate functions to be operated. I did this on a Hornby class 56 diesel very recently to separate out the lighting functions at one end, allowing me to run with or without tail lights in either direction. Since this wasa sound-fitted loco, I chose to test my wiring first with a cheaper non-sound decoder, before plugging the sound decoder back in once I was satisfied all was well.

Bigmet
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Bigmet » Mon Jun 01, 2020 10:58 am

The greatest problem you may find with such a project on the J11 is the space to neatly route all the extra wires. At a wire per lamp and one for the firebox, and the blue return wire, that quickly becomes a thick bundle with the track supply and motor circuit wires already running between loco and tender; and the flexibility for the loco and tender to swing relative to each other for curves has to be maintained. Careful planning time...

The only RTR OO steam tender loco model with any wiring provision for lights that I know of is the Stirling single from the NRM, manufactured by Rapido. I learned recently that it has a firebox flicker fitted, however I haven't seen it because I haven't switched the lights function on... The loco to tender connection is a great lump of a multipin plug and socket, which I am going to either adjust or remove when I feel brave enough. This because it is visually intrusive, and results in an excessive gap between the loco and the tender, which takes the edge off the very fine overall appearance of the model. I rather hope that this isn't a fashion that is going to catch on. It might be just about acceptable largely hidden between the deep outside frames of an LNER wide firebox loco and tender, but not on some dainty piece of Victoriana.

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Michaelaface
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Michaelaface » Mon Jun 01, 2020 2:13 pm

Ironduke wrote:this seems like a useful guide:
http://www.dccconcepts.com/wp-content/u ... e-2014.pdf


already looked at that and as far as I can see it doesn't mention where to connect the wires to the loco PCB, which is why I was guessing at the actual pins, but I don't want to go ahead and do that and risk damaging the loco

SRman wrote:You can solder to the decoder; most do have solder pads on them for this. However, I am too timid to do this as too much heat could destroy the decoder. In the absence of solder pads on the lcomotive PCB, I solder to the base of the pins. This also allows the use of different decoders if it becomes necessary to swap them later.

It still takes a steady hand and good eyes to do the soldering but it does allow for separate functions to be operated. I did this on a Hornby class 56 diesel very recently to separate out the lighting functions at one end, allowing me to run with or without tail lights in either direction. Since this wasa sound-fitted loco, I chose to test my wiring first with a cheaper non-sound decoder, before plugging the sound decoder back in once I was satisfied all was well.


yeah I saw that somewhere, but I really don't want to go anywhere near the decoder with a soldering iron as it was rather expensive, but if soldering to the base of the pins is a tried and tested method I'll go with that, thank you

Bigmet wrote:The greatest problem you may find with such a project on the J11 is the space to neatly route all the extra wires. At a wire per lamp and one for the firebox, and the blue return wire, that quickly becomes a thick bundle with the track supply and motor circuit wires already running between loco and tender; and the flexibility for the loco and tender to swing relative to each other for curves has to be maintained. Careful planning time...

The only RTR OO steam tender loco model with any wiring provision for lights that I know of is the Stirling single from the NRM, manufactured by Rapido. I learned recently that it has a firebox flicker fitted, however I haven't seen it because I haven't switched the lights function on... The loco to tender connection is a great lump of a multipin plug and socket, which I am going to either adjust or remove when I feel brave enough. This because it is visually intrusive, and results in an excessive gap between the loco and the tender, which takes the edge off the very fine overall appearance of the model. I rather hope that this isn't a fashion that is going to catch on. It might be just about acceptable largely hidden between the deep outside frames of an LNER wide firebox loco and tender, but not on some dainty piece of Victoriana.


ahh yes that is the next challenge, the DCC concepts lamps have very thin wires which, look like they'll solve at least some of that issue

thanks for the responses everyone, I'll give it my best shot and report back with how I get on

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Michaelaface
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Michaelaface » Mon Jun 01, 2020 11:07 pm

I can confirm my work to be a success, lesson learned is I really need to invest in some heat shrink, I also didn't wire in the LED for the firebox flicker, as the LED I chose to use doesnt seem to have been the best, also included a video showing everything running fine

https://www.youtube.com/watch?v=X5miHtoWj2s&feature=youtu.be

Image

Image

Image

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Ironduke
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Ironduke » Tue Jun 02, 2020 1:15 am

Michaelaface wrote:already looked at that and as far as I can see it doesn't mention where to connect the wires to the loco PCB, which is why I was guessing at the actual pins,


On page 1 it shows what colours to use for front (white) , rear (yellow), firebox (green) and common (blue) then on page 11 it shows which colour applies to each pin on the 21pin header.

If in your photo green is for the firebox LED then, according to the document, you have the green on the wrong pin; it should be right next to the blue, directly opposite the white.

Nice work otherwise, though.
Regards
Rob

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Michaelaface
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Michaelaface » Tue Jun 02, 2020 2:21 am

Ironduke wrote:
Michaelaface wrote:already looked at that and as far as I can see it doesn't mention where to connect the wires to the loco PCB, which is why I was guessing at the actual pins,


On page 1 it shows what colours to use for front (white) , rear (yellow), firebox (green) and common (blue) then on page 11 it shows which colour applies to each pin on the 21pin header.

If in your photo green is for the firebox LED then, according to the document, you have the green on the wrong pin; it should be right next to the blue, directly opposite the white.

Nice work otherwise, though.



ahh no what I meant was, would I be literally soldering the wires to the pin or was there a tab somewhere I just wasn't seeing, as soldering directly to the pin didn't seem right somehow, so I just wanted to be sure, and re the wire colours they were just some spare wires I had left over from something else, I used the green wire on an 8 pin decoder for the firebox flicker on another loco, and this decoder had firebox flicker on aux 3 so in my brain I just decided to associate firebox flicker with the green wire

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SRman
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby SRman » Tue Jun 02, 2020 4:26 am

Some PCBs and some of the decoder interfaces have solder pads, some don't. I have seen a few 21-pin boards with the solder pads right at the bases of the pins, and others that spread the pads out further away from the pins. I have been unlucky in that the Bachmann class 20 and Hornby class 56 where I added light functions both lacked solder pads for what I wanted to do.

I did add lamps (the same DCC Concepts type you want to use) plus a firebox flicker to a Hornby Hogwarts Castle as a bit of fun: that was an earlier non-DCC-ready model, so was hard-wired. Also, as this model only required the white wire to supply the front lamps, and the blue for the return current, I used the yellow wire to supply the firebox LED, and programmed both to stay on permanently on F0, but with the flicker effect added to the yellow wire. The decoder I used for that was a TCS M1, so only had the two functions available.

Image
Wiring Up Hogwarts Castle - 10 by Jeffrey Lynn, on Flickr
Last edited by SRman on Tue Jun 02, 2020 9:45 am, edited 1 time in total.

Bigmet
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Bigmet » Tue Jun 02, 2020 9:38 am

Michaelaface wrote:...thanks for the responses everyone, I'll give it my best shot and report back with how I get on

And a good shot it proved to be.

When it comes to heat shrink insulation, something to be avoided is shrinking it on tight over the whole length used, if the wire(s) have to be able to flex little as the model moves on the track. Shrinking just the ends onto the wire(s), leaving the middle more flexible is a good plan.

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Michaelaface
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Michaelaface » Thu Jun 04, 2020 2:40 pm

SRman wrote:Some PCBs and some of the decoder interfaces have solder pads, some don't. I have seen a few 21-pin boards with the solder pads right at the bases of the pins, and others that spread the pads out further away from the pins. I have been unlucky in that the Bachmann class 20 and Hornby class 56 where I added light functions both lacked solder pads for what I wanted to do.

I did add lamps (the same DCC Concepts type you want to use) plus a firebox flicker to a Hornby Hogwarts Castle as a bit of fun: that was an earlier non-DCC-ready model, so was hard-wired. Also, as this model only required the white wire to supply the front lamps, and the blue for the return current, I used the yellow wire to supply the firebox LED, and programmed both to stay on permanently on F0, but with the flicker effect added to the yellow wire. The decoder I used for that was a TCS M1, so only had the two functions available.

Image
Wiring Up Hogwarts Castle - 10 by Jeffrey Lynn, on Flickr


I'm starting to think hardwiring decoders into locos might make installing sound, lights, etc considerably easier, when trying to fit everything into my jinty the 8pin plug and pcb just seemed to constantly be in the way, and on the J11 I had to change the position and orientation of the PCB to fit the speaker in

Bigmet wrote:
Michaelaface wrote:...thanks for the responses everyone, I'll give it my best shot and report back with how I get on

And a good shot it proved to be.

When it comes to heat shrink insulation, something to be avoided is shrinking it on tight over the whole length used, if the wire(s) have to be able to flex little as the model moves on the track. Shrinking just the ends onto the wire(s), leaving the middle more flexible is a good plan.


will take this on board for future projects!

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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Bigmet » Thu Jun 04, 2020 3:25 pm

Michaelaface wrote:...I'm starting to think hardwiring decoders into locos might make installing sound, lights, etc considerably easier, when trying to fit everything into my jinty the 8pin plug and pcb just seemed to constantly be in the way, and on the J11 I had to change the position and orientation of the PCB to fit the speaker in...

I really only use DCC to run the motors, and about half my RTR have the decoder hardwired because the manufacturer made such a poor job of the socket placement, and several more have the socket released from a poorly thought out mounting. I have quite a list now:

No void adjacent the socket large enough to take a decoder, or a path to route wires to a large enough void.
Socket and void right where weight needs to be, when there's adequate volume elsewhere for it.
Socket 'neatly on the centreline' in the void, leaving insufficent space for a decoder, whereas mounted off centre there would be ample space.
Socket clumsily mounted on a 'tower'in the void, leaving insufficent space for a decoder, 'eating' what would otherwise be ample space.
Socket has structure around it that fouls the blanking plug firstly making body removal for access a test of strength, and decoder installation impossible without internal modification.

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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Suzie » Thu Jun 04, 2020 11:34 pm

There is an answer to the decoder space problem, and that is for loco manufacturers to use one of the sockets that has a defined space, i.e. any of the PluX sockets. Any manufacturer can use them, decoders are readily available for scales from 'Z' to '0', a small decoder will plug into a big socket if you don't need much functionality, and the 22-pin versions have more functionality than any other socketed decoder. The Next-18 and Next-18S are nearly as good but don't cover the complete range of scales (too big for 'Z', too weedy for '0') and do not have enough functionality for top end locos so there is little point in manufacturers using them.

Virtually all locos with an NEM652 8-pin socket could have their PCBs replaced with one with a PluX-16 socket and have space to spare for a speaker.

The new defined space sockets and decoders have been around long enough that there is no excuse to still be using ridiculously outdated sockets with inadequate functionality and poor reliability. I can see the day when there will be rioting in Barwell and Margate.

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SRman
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby SRman » Fri Jun 05, 2020 1:14 am

Suzie wrote:There is an answer to the decoder space problem, and that is for loco manufacturers to use one of the sockets that has a defined space, i.e. any of the PluX sockets. Any manufacturer can use them, decoders are readily available for scales from 'Z' to '0', a small decoder will plug into a big socket if you don't need much functionality, and the 22-pin versions have more functionality than any other socketed decoder. The Next-18 and Next-18S are nearly as good but don't cover the complete range of scales (too big for 'Z', too weedy for '0') and do not have enough functionality for top end locos so there is little point in manufacturers using them.

Virtually all locos with an NEM652 8-pin socket could have their PCBs replaced with one with a PluX-16 socket and have space to spare for a speaker.

The new defined space sockets and decoders have been around long enough that there is no excuse to still be using ridiculously outdated sockets with inadequate functionality and poor reliability. I can see the day when there will be rioting in Barwell and Margate.


At risk of hijacking Michaela's topic, I agree with you about the uselessness of persisting with the 8-pin interface (Hornby, I am looking at you in particular, but others are also guilty of hanging onto this). Bachmann have been smart in that when they started adding sound using the 21-pin interface, they kept a standardised PCB for all of the variants of the same model, with or without sound. That made it easier to add sound if required with the solder pads already there for the speaker wires. Very few manufacturers have taken advantage of the extra outputs available with the 21-pin interface, to separate light functions, for example (Dapol have started with this though). The PLuX 22 gives even better access to separate functions, if the PCB design allows for it (don't be lazy, manufacturers). I have a Piko Expert German BR 112 locomotive that uses the PLuX 22 to full advantage with an 8-function decoder, and that is really good. I have an Australian EMU that uses 21-pin decoders (plural), has no interior lights but does have head, tail, ditch, marker and guard's position lights; the manufacturer has been extremely lazy in having the head and tail lights directional, and all other lights on physical switches, operated on DCC through the same function as the head/tail lights - a total waste of the potential of the 21-pin interface, and could probably be even better if it had used a PLuX 22 and a PCB with separate tracks for each output.

I can see a use for the Next-18 interface as it can be kept low and flat for tight installations (particularly for sound) in things like small shunters.

Bigmet makes some good points too about the sockets taking up what would otherwise be useful space. I have mentioned the Hornby M7 0-4-4T as an example, where the socket is at the front where weight is needed, while the bunker is empty and impractical to use for added weight as this would throw the weight off the driving wheels. Hard-wiring these is a good idea, then packing as much weight as possible into the void left from the socket location.

Sorry: rant over. Normal programming can resume. :)

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Michaelaface
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Michaelaface » Fri Jun 05, 2020 2:42 am

Hijack away, lots of very interesting points here, in an area I want to learn more about


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