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

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

Postby Suzie » Fri Jun 05, 2020 9:41 am

I will concede that the 1.9mm reduced thickness of the Next-18S compared the the PluX-16 near equivalent sound is nearly a scale foot in 'N' so manufacturers might be swayed to use the thinner solution, but I think that on the whole this is easily worked around.

Zimo already make a sound decoder (MX648p16) (20x11x4mm) that will fit in the space allocated for a non-sound PluX decoder (20x11x4.2mm), and which is smaller than the space required by a Next-18S decoder (25x10.5x4.1) in all but one dimension - and then it only misses by half a millimeter in width with overall volume much smaller.

Technology and good design have moved on and surpassed the standards making them already partially obsolete, and removed the whole (functional) reason that Next-18 exists for (probably still a political reason, but that should not be made in to a problem for consumers and retailers).

In conclusion, if you have 4.1mm thickness and cannot run to 4.2mm, then you are stuck with Next-18 as the only option. If you have 9.5mm width and cannot go to 10mm then you are stuck with Next-18. Beyond that you can specify a space for a non-sound PluX-16 and fit a speaker, and people can just plug in a Zimo MX648p16 and have sound anyway!

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

Postby Bigmet » Fri Jun 05, 2020 11:31 am

SRman wrote:
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...
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defined space sockets and decoders have been around long enough that there is no excuse to still be using ridiculously outdated sockets with inadequate functionality and poor reliability...


...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...

Has to be said that yet another plug and socket system doesn't solve the problem of designers putting it in an awkward to access space or an inappropriate location where weight would ideally go. And since a designer has made the space too narrow for an MTC 21pin blanking plate such that it is a wrestling match to get the tender top off (Rapido, Stirling single tender) Plux can't fix that type of designer oversight either.

Plux is old news in 2020 anyway, very last millennium, obsolescent from introduction. Failed to get adopted for whatever reason, (the UK market players that said they were going to go with it didn't for some reason - do we know why?) and it was so wonderful that the neat little 'Next18' was found to be necessary shortly after Plux arrived: frankly Next18 is a much better concept from my perspective and is 2/2 'faultless' to date: optimally positioned, simple access. I'll settle for that, especially as there is an economy Zimo decoder available!

But better yet would be a decoder with a card type edge connector that inserts in a slot from outside the model. That's a self gauging 'go/no go' implementation of a decoder socket and void. The designer can then only get it wrong by placing it where weight should be, but if compact even that would not be a major problem.
Last edited by Bigmet on Fri Jun 05, 2020 11:33 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 » Fri Jun 05, 2020 11:32 am

post deleted

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

Postby Suzie » Fri Jun 05, 2020 4:35 pm

Quite agree that the decoders should go in a sensible location, and there should be no difficulty finding space in a tender under an easily removable coal load or in the fuel tank of most diesels, or maybe a removable roof panel, just like the prototype.

Edge connectors tend not to be used so much nowadays because to be reliable they have to be very well engineered - and that does not correspond with cheap. A blanking plug should never be larger than a decoder, so there should never be an issue fitting one in - that type of error is just mad.

I think we are still seeing the after effects of lazy design from the olden days where the PCB was just slapped on top of the motor because that is the way it was always done. Modern CAD design should allow things to be put in spaces that until now might not be considered due to the number of prototyping iterations it would take to get it right. Nowadays those proficient with CAD can use all the simulation and modelling tools to get it right before anything needs to be prototyped, and it is quite normal in most industries now to get the CAD right first time - changes only required when people get wind of what could have been done if the specification had been a bit more imaginative!

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

Postby Ironduke » Fri Jun 05, 2020 10:53 pm

Suzie wrote:Edge connectors tend not to be used so much nowadays because to be reliable they have to be very well engineered


Extremely well engineered to fit at least 8 contacts in the space of 10-16 mm, and gold plated.

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

Postby Suzie » Sat Jun 06, 2020 12:09 am

Quite, with everyone hanging on to the deprecated standards that don't actually do the job!

I cannot see an 8-way edge connector being very useful any more (the jst-9 was not far from this I guess in practical application), especially when it is bigger than 10mm, the 2x8 pin headers used in PluX are only 10mm and have fifteen usable gold plated contacts.

The days when 8-pins was sufficient for anything other than a minimum space loco (Z-scale without sound for example) are long gone. Take a steam tank loco, you have:-
a, Track (2-wires)
b, Motor (2-wires)
c, Speaker (2-wires)
d, Stay alive power store (2-wires)

Now where are you going to wire the firebox flicker LED?

The way you keep things simple is a single socket that has connections for everything you will possibly need in the loco so that you can plug in exactly which decoder meets your need from a simple £20 12-pin motor and four functions right up to a fully featured 22-pin sound decoder if the loco warrants that sort of complexity. There is only one socket system that offers this currently (PluX), and it just needs loco manufacturers to use it and fit the socket in a sensible place!

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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 15, 2020 7:09 pm

while this thread is still relevant, has anyone used components from here before? looks like they would make fitting lights etc a lot easier, plus I also need a replacement socket for an n gauge loco

https://www.illuminatedmodels.co.uk/collections/dcc-socket

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

Postby Flashbang » Mon Jun 15, 2020 8:18 pm

Main thing is... Is there room for anything additional? Many locos just wont have the space or headroom for additional PCBs.
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Suzie
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Re: Fitting lights to a steam loco with a 21 pin decoder

Postby Suzie » Mon Jun 15, 2020 10:04 pm

The NEM651 6-pin one might work, but when using this socket it is usually best to get a socket with wires attached since the PCB serves no real purpose (in practice you don't need the V+ connection).

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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 16, 2020 1:10 am

Flashbang wrote:Main thing is... Is there room for anything additional? Many locos just wont have the space or headroom for additional PCBs.


wouldn't be additional, would be to replace the ones that are already there to make soldering the various wires for lights etc a lot easier in the case of 21 pin decoders

Suzie wrote:The NEM651 6-pin one might work, but when using this socket it is usually best to get a socket with wires attached since the PCB serves no real purpose (in practice you don't need the V+ connection).


and here is my issue re the 6 pin pcb, the blanking plate was apparently glued in and tore the whole socket out with very little force, and when I took the pcb out of its housing to try to work out just what went wrong, several of its solder joins failed, do I actually need anything thats on that pcb? if i just get a 6 pin harness thingy and wire that in will it work okay?

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Suzie
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Re: Fitting lights with a 21 pin decoder and other tedious decoder questions

Postby Suzie » Wed Jun 17, 2020 12:29 am

No, you don't need anything on the PCB.

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Bufferstop
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Re: Fitting lights with a 21 pin decoder and other tedious decoder questions

Postby Bufferstop » Wed Jun 17, 2020 11:07 am

Designers seized upon the PCB as the place to put the suppressors for DC operation, making it take up more space. They should put them on the blanking plug, then the space would be recovered when it's removed to put in the decoder.
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Bigmet
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Re: Fitting lights with a 21 pin decoder and other tedious decoder questions

Postby Bigmet » Wed Jun 17, 2020 4:00 pm

Bufferstop wrote:Designers seized upon the PCB as the place to put the suppressors for DC operation, making it take up more space. They should put them on the blanking plug, then the space would be recovered when it's removed to put in the decoder.
Oh yes. It's so obvious to anyone with even a basic grounding in matters electrical, that I do wonder about the general technical grasp of those engaged in model design.

Michaelaface wrote:...here is my issue re the 6 pin pcb, the blanking plate was apparently glued in and tore the whole socket out with very little force, and when I took the pcb out of its housing to try to work out just what went wrong, several of its solder joins failed...

Done yourself a favour there, indirectly; eliminated a bunch of flaky soldered joints. Now, in your shoes I would next go round every circuit you want to continue using in the model and test every soldered connection before doing anything further, and remake all the 'fails'. Because it's quite likely there are more, and the last thing you want is to keep having to revisit the model because elements suddenly stop working or go intermittent.


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