DCC controlled Hornby turntable using Rail master

[walkingthedog]

Cross bar exchanges, uniselectors those were the days. I had a tool kit, I could adjust the tension on the contacts on a relay, install new equipment. I did a bit of everything in training from erecting telegraph poles to installing new equipment. My first

 

job in the exchange construction part of the training was to solder the wires from a 5000 pair cable onto a distribution frame. Still quite good at soldering.

[walkingthedog]

It is due to my training that I can completely dismantle a loco and put it back together in working order and wire a layout in DCC or DC.

These skills will disappear over the next few years because nobody will know how to do anything but plug something

 

in or change a programme.

You only have to look at some of the questions on the Forum, 80% are common sense.

[Graskie]

I don't think you do know how to wire a DCC layout, WTD. Have you ever done it? Is that your secret reason for not having done so with your own?

[Graskie]

And anyway, I can dismantle a loco, even if I can't put it back together again!

[walkingthedog]

I have wired a couple of DCC layouts Graskie. If you can wire DC, DCC is simple. You don't have to own something to be able to work on it. I've changed the wheel on a Boeing 747 but I haven't got one.

You should be able to dismantle a loco because

 

you, like me, are from the generation that fixed things when they broke. I think fixers will disappear. Everything will have to be sent back to an expert.

[Graskie]

But have you ever wired a DCC layout with live frogs? And what on earth would you want a 747 wheel for anyway?

[walkingthedog]

Yes. Seem to recall it entailed isolating the live frog and attaching bridging wires or was that for something else. Wired so many layouts for different people I can't remember.

I've also run a goods train with a toad at the rear.

[walkingthedog]

Graskie said:

And what on earth would you want a 747 wheel for anyway?

[walkingthedog]

Graskie said:
And what on earth would you want a 747 wheel for anyway?

I didn't want one, that's why I changed it.

Talking of points I see the other company make them wired so you don't need point clips.

[Graskie]

Yes, and they look much better for it. So you can't remember how you messed up with DCC wiring either?

[Fishmanoz]

Well haven't you 2 been having fun while it was dark over here?

 

Know which end of a soldering iron is which, but certainly no large cable terminations in my background, no 747 wheels in my garage, and I haven't seen my jumbo jack in some time either.

 

I suspect the hobby will continue to attract the type who started life pulling their toys apart to find out how they worked, and got some of them back together, although maybe not if the playing was the pulling apart.

 

And I think you are going to have

 

to work harder Graskie - he's not biting and seems to remember for the live frog to isolate and switch polarity with point throw.

[Graskie]

Does he? I don't think he's said that yet. What he did say was that he'd forgotten. He should know now, though, given that you have just advised him, Fishy.

[walkingthedog]

I don't mess up any wiring. It just needs to be properly done and kept neat.

Having said that, why does the back of my TV/HI-FI look like an explosion in a knitting factory?

 

The new other company points that are wired for DCC have to be better

 

than using clips. As DCC needs everything to be electrically sound surely the clips are just another thing to cause problems.

[walkingthedog]

Not sure how long you've had a model railway Graskie but I've been building and running them for 54 years, with a little help from my dad early on.

[Graskie]

The back of my TV is just the same. In fact there are certain connections I still haven't figured out. It doesn't help with changing types of connections if your mixing old with new. I had my first trainset almost 60 years ago, without any help from my

 

dad. The funny thing is that he was fitting some wall lights on the chimney breast many years back and he kept blowing the circuit. I eventually came to his aid with just the knowledge I'd acquired from wiring a simple model train layout.

[walkingthedog]

Well there you go then. Don't think my dad trusted me with a soldering iron when I was 10. Come to think of it I think the only one he had needed to be heated on a gas ring.

 

Talk to you later.

[Graskie]

We couldn't afford gas when I was a kid, nor a soldering iron if it comes to that.

[Fishmanoz]

No soldering irons in my house until I bought one as a teenager. My friends grandad had one and it was heated with a blowtorch.

 

WTD, I think you goods train must have come from North Qld. They certainly come with live toads amongst the goods -

 

cane toads.

[walkingthedog]

I saw some cane toads in a zoo near Perth WA. Think I prefer the GWR versions.

[Howhoward7]

Just going back to the turntable for a moment, LMSTim, did you reduce the dwell time too?

[Fishmanoz]

Lots of Queenslanders reduce cane toad dwell time with a golf stick. Fore!!!

[Blackbird]

Fishmanoz said:

.blackbird, I beg to differ about polarity being a DC only concept. I think it works just as well in AC, or in this instance DCC. I would be happy to be perfectly correct and talk about in phase or 180 out of phase but that

is getting a little technical. And the fact is, even with isolation, if an outlet connects to the layout 180 degrees out of phase, you will still get a short circuit.

In summary, I stick by my last post.

Also, if what you are saying is correct,

are you trying to say an RLM is never needed in DCC, even to run a reversing loop?

[Fishmanoz]

Blackbird?

[Blackbird]

Fishmanoz said:

.blackbird, I beg to differ about polarity being a DC only concept. I think it works just as well in AC, or in this instance DCC. I would be happy to be perfectly correct and talk about in phase or 180 out of phase but that

is getting a little technical. And the fact is, even with isolation, if an outlet connects to the layout 180 degrees out of phase, you will still get a short circuit.

In summary, I stick by my last post.

Also, if what you are saying is correct,

are you trying to say an RLM is never needed in DCC, even to run a reversing loop?

[Blackbird]

Hi Fishmanoz, First, sorry for delay in reply, I've been watching additional comment which have gone well off track of the original query. I answered with relevence to the definition of 'polarity'. Only DC systems can be described with polariy, +ve & -ve.

 

I am perfectly happy to discuss AC and phase, but it is the cross connection that is the problem, and I think that Hornby's terminology of; 'A' & 'B' tracks is the best reference.

With the Hornby R070 turntable in original configuration, running with DCC

 

track suppy, a short will occur as soon as the bridge is rotated. This is because the bridge is permanently connected to the inlet track via the under-rail contacts, which means that the left rail connects with the right rail. Or whatever terminoligy is addressed

 

to the rails; +ve, -ve, A, or B, not polarity!

This problem can be rectified by isolation. Hornby advise removing all of the Turntable pick-up contacts, this of course works, but means that the selected outlt has to be connected to the DCC supply, and that

 

supply has to be matched to the supply at the inlet (it is still connected to the bridge). All feasible, but impracticable. The simplest solution is to isolate the inlet track between the under-rail contacts and the bridge contacts. (This is the basis of the

 

DCC turntable track converter). This allows the selected, or aligned track to supply the feed. Unless the selected track has an alternate feed there is no 'short circuit'.

I did not say; RLM is never needed with DCC, only with this configuration, it isn't

 

always neccessary!