DCC Digitrax Stationary Decoders and Seep point Motors

[mumbles]

Hi
Just a quick photo log of how I fitted a pair of Seep point motors and a Digitrax DS 52 Stationary Decoder
[please excuse the slightly blurred pics in some of these but I can't retake them and they are clear enough for the purposes]

Assemble all parts and tools needed

Lay out decoder and motors to see they don't foul droppers and each other, this also allows to measure roughly how long the wires need to be to and fro

Double check under the board

Cut all the wires needed [although blurred you can see the 2 red and 1 black between motor and decoder [x2] and the green wires for frog polarity. and the long red and black power lines to the bus]


Tin all the wires [flux first]

Tin the motor contacts

Solder the wires to the motor, the red and black will go to the decoder, the green will go to the Bus for power for frog polarity switching

The last contact to solder [F] is the dropper from the point frog [which was done when the track was laid]

Wire into the decoder... nice and easy screw terminals [with the wire tinned for added strength]

Locate the point motor.. making sure that it throws the point both ways. and screw in place


Solder power to the decoder from the Bus

Check it works

Trim the motor arm

Solder the feeds from the point motor to the Bus

1st motor..Check for shorts with loco... don't get distracted here!

2nd one...ooo crazy reading on Zephyr =short.. so switch over those green wires on the Bus

This little jumper is for programming the decoder addresses, closed to programme, open to operate

Nasty peco motor mounts.. trim trim trim

Job Done
Playtime!

My thread
Michael

[Ironduke]

nice job, mr michael.

just a quick question, why don't you use rosin core solder?

[mumbles]

nice job, mr michael.

just a quick question, why don't you use rosin core solder?

I did have some for a while [i think, it that the stuff with a flux core?] but ran out so got this stuff and the flux. i must say since then i have found soldering easier.. it's like the flux drags the solder into the joint
Michael

[Ironduke]

Yes it does, it's magic stuff but it's not really made for electrical work. The melted flux capillaries up inside the insulation and corrodes the wire eventually. Rosin is not flux, that's why they use it :^)

[SouthernBoy]

Good illustrated step-by-step, and thanks for posting ... but I need to ask a couple of really dumb questions:

1) I understand about tinning the ends of wires - but what exactly is flux and when do you/don't you use it when soldering on model railways? Are there different types for different purposes?


2) I know you can have a 'common return' for power feeds to tracks, but didn't think you could have them for points (which it looks like in the back of this picture) - or is this a DCC only thing - not for DC (which I will be) ?


Sorry, don't mean to hijack the thread - just seemed like an appropriate moment for an electrical numb-skull to ask a couple of questions.

Thanks

[mumbles]

1] as i understand it, flux cleans the work as you apply solder so the join is a good one. although Rob seems to be saying it is not the best thing for electrical work. basically, i think that all metals will have impurities on them which the flux, when heated with a 'tinning' removes, making the bond as efficient as possible. I stand to be corrected, i'm no expert. i think there are different types, mainly lead and lead free.. i have lead free.., which i believe is best
2] the wiring is slightly different to how you may have seen with my DC control panel in the attic. i have used these seep motors for both that, and this DCC system and the set up is different. Here what you have is the 2 red and one black wires going to the decoder to throw the point motor. the green wires you see are attached to the microswitch on the point motor that then changes the polarity of the frog. as you can see. the red and black power feeds of the bus [bare copper wire with coloured tags] run into the microswitch [2 green wires] and the the 3rd green wire goes to the frog on the point. when the decoder throws the point, the microswitch changes which polarity from the bus [red>d or black>e] goes to the frog [via f]. hence why you can get a short.. trial and error works fine!
Here is a diagram to explain more I hope!


not hijacking at all. the reason i keep the writing to a gordon ramseyish style of:
tin
solder
screw
play...
is that questions pick out the things the pics don't explain without having to write thousands of words that the pics already said!
cheers
Michael

[Ironduke]

1] as i understand it, flux cleans the work as you apply solder so the join is a good one. although Rob seems to be saying it is not the best thing for electrical work. basically, i think that all metals will have impurities on them which the flux, when heated with a 'tinning' removes, making the bond as efficient as possible. I stand to be corrected, i'm no expert. I think there are different types, mainly lead and lead free.. i have lead free.., which i believe is best

Sorry: long, technobabbly, boring paragraphs coming up. Skip to the end if it's too hard.

I don't know if flux comes in lead and lead free..solder does. There may be flux that is intended for electrical use - possibly where there are large electrical wires to connect in an industrial situation.
Flux works in two ways:
1. It is acidic so it reacts with the oxidised surface of metal and cleans it.
2. Metal oxidises faster when it's heated by the soldering iron. Flux flows over the surface of the metal to keep air away from it and stops it from oxidising. Both the copper and the solder oxidise when heated.

The trouble with Flux is the acidic bit. If you leave it on the metal it will eventually eat it away. With a white metal or brass kit you wash it off. With a copper pipe there's so much copper that the flux can't eat right through it before it loses potency.
With a small electrical circuit however it isn't really practical to wash it and you would never be able to wash it out from under the insulation on a wire. So instead of flux we use rosin (we still call it flux but that's technically incorrect). Rosin is only slightly acidic and mainly it just "washes" the surface clean and protects it from the air during soldering. In PCB manufacture we still wash the rosin off but that's mainly for cosmetic reasons.



To paraphrase a gentleman I know,
"Just buy the *ing rosin core!" :^)

[mumbles]

"Just buy the *ing rosin core!" :^)

[mumbles]

meant to ask... when you say eventually eat away the metal.. how long are you meaning?

[SouthernBoy]

I think the moral of the story is:
The more you learn, the more you find there is still to learn.

All very useful information though ...

[Ironduke]

meant to ask... when you say eventually eat away the metal.. how long are you meaning?

I couldn't tell you :^)

You'll see the wire go green and brittle so that it just snaps off one day.