Turntable R070 Connection [on a DCC layout]

[Chrissaf]

Would I  just connect the wires from my Hornby controller to the wires from the motor bypassing the switch that comes with the turntable using the controller dial for power and forward/reverse button for turntable direction?

Yes, that’s exactly what I’ve done.  I run DC, never looked into DCC but on my DC layout I cut the wires from the pictured controller you posted and wired it straight in to the outcoming turntable wires. I don’t remember my same turntable having a switch though to bypass,though it may now thinking about it have come with one, unless that is a DCC thing, I don’t know.

from what you say though, you’re already using your spare controller?

[Chrissaf]

I'm looking at buying the R070 motorised turntable and have a couple of questions I hope you guys can help me with.

Not sure what to use for a power source.

Firstly I'm not electrically minded, amps and volts means nothing to me, so need help in English :)

I have a Hornby  standard controller with power supply that I dont use anymore.

I cut the plug off the end that powers the track as I needed it for my NCE Powercab DCC setup that I now use.

Am I able to use the Hornby controller to power and turn the turntable?

Would I  just connect the wires from my Hornby controller to the wires from the motor bypassing the switch that comes with the turntable using the controller dial for power and forward/reverse button for turntable direction?

Or would I just connect the wires from my Hornby controller to the wires from the switch?

This one seems easier and more practical.

Plan B is I can use my NCE Powercab to control the turntable?

Theres a DCC decoder for it that I'm guessing the turntable"s motor would directly plug  into?

But as I'm new to DCC I'm not sure how the turntable would power up this way.

Is this an easier and cheaper option?

To be honest this seems easiest, just connect the wires from my Hornby controller to the wires from the switch, but thats why I'm here asking I dont really know.

I just want the easiest less mess way of doing this.

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[Chrissaf]

You say that electrickery is a complete mystery to you. Just be aware that out of the box, the R070 Hornby Turntable is constructed and wired for DC Analogue layouts, and will generate short circuits on a DCC powered layout as the bridge track turns.

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If you are going to use the R070 on a DCC layout then electrical and wiring modifications need to be made either to the outlet track connections or the R070 TT itself. The modifications (if fully implemented) also require additional DCC power connections wired to the outlet tracks on the TT, some of which have to be connected in reverse compared to the others. This typically requires a DCC Bus wiring system with dropper wires soldered directly to the outlet rails. The description in your post indicates that you do not currently use a DCC Bus power wiring system. This level of installation, requiring soldering, may not be within your skill set.

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Perhaps before committing 100% to the purchase of a R070 TT, it might be prudent to review the 'recommended' modification guidance (put together by members of this forum in the form of a 'How To' tutorial) and decide whether the modification is something within your skill set.

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This modification for DCC working is the same and still required regardless of what solution you use to power & control the rotation motor. Start reading from the 3rd post down on the page that opens.

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R070 Turntable DCC Modification 'How To' tutorial.

http://www.hornby.com/uk-en/forum/r070-hornby-turn-table-to-dcc-including-images/?p=1

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There are more expensive (non Hornby) turntables on the market that are DCC friendly 'out of the box'. After reading the modification guide, you might want to consider digging deeper into your pockets for one of those instead.

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The switch included with the R070 Turntable is optional and for use on a DC Analogue layout only. Its function is to allow the same DC Analogue controller that is being used to control the loco on the track to also be used to control the Turntable rotation motor, in a 'one or the other' configuration. The switch is not needed if you have used a separate different power source (or a DCC decoder) to operate the TT rotation motor independently of the loco on the track.

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Just as an aside comment. You say that you have used the track power connection 'cut off' from the Hornby DC Analogue controller to use with your NCE Power Cab. Just be aware that if you are using either the Hornby R602 or R8206 track power clip / power track for the final connection to the actual track. That these two Hornby parts contain DC Analogue suppression capacitors that can adversely affect DCC signals. If you are observing any strange and intermittent control issues with your DCC locos, then those issues are almost certainly down to the presence of those capacitors. Even if you are not currently observing any DCC control issues, intermittent or otherwise. Check your Hornby power connection clips (if you are using them) for the capacitors and remove any that you find.

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This also includes any and all R8201 link wires that you might have installed. These contain the capacitors too.

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The capacitors need to be removed for correct DCC layout operation.

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[mjb1961]

Hi,,,,,run it off your powercab,follow hornbys instructions to convert to dcc,they are on this site,or follow a fellow hornby forum members instructions ,either way will have you running it from your powercab ,I don't see the point in running the turntable in DC when the layout is dcc and you say you have a decoder with the turntable ,you may find that there is no socket for the decoder to plug in ,it's not that easy!!,you will have to strip wires and solder ,,,,let us know how you get on ,,,,mjb

[Fishmanoz]

Hi Storm, welcome to the forums. Three replies and 3 different answers, but will they all work?

 

Unfortunately lb’s won’t as it is for DC not DCC (as implied by Chris).  Chris’s most certainly will, it being pretty much a consolidation of the views of a number of forum members and includes photos for clarity.  Mjb’s will too, being just the Hornby method, but Chris’s will be easier to follow.

 

PS.  I could complicate things for you further by giving you a fourth, an elegant solution (in my view) developed by previous forum member Blackbird and for which he once sold a modified (gapped) inlet track.  But better to stick with Chris’s link.

[Storm68]

Thanks guys, a lot of food for thought.

I didnt know about not being able to run a dc accessory on a dcc layout so thank you for that.

I'll check for that capacitor too.

My power connection to the track is a little different to the one in the photo that came with my Flying Scotsman set.

 I'll post a photo.

If there is no capicator am I good to go in dcc mode or is it just easier to buy a straight with the right connection which to be honest as I'm new after a 40 year lay off I have no idea which track part I'd need.

Also is there a certain dcc decoder I need or any one will do?

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[TrainDriverJ]

I appreciate there is an official Hornby conversion and a multitude of discussions by members that takes ages to consider in detail and read leading to one that is favoured.

 

But has anybody had a stab at what they believe are the simple pros v cons of the differing methods of DCC conversion that I may read and weigh up?

[Chrissaf]

Normally, the tan coloured buttons indicate the the power connector is Analogue and will more than likely contain a capacitor underneath that domed cover that is positioned between the track rails.

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If you don't want to modify the existing power connector, the DCC replacement is an R8241 (note the black / dark grey colour on the buttons) or an R8242.

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R8241                                                                   R8242

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With regard a decoder that is suitable for the R070 TT. Any basic 'motor control' decoder will do. Doesn't even need to be Hornby branded. But the Hornby R8249 decoder is compatible.

[Storm68]

Thanks guys, I'll grab the R8241 today.

After looking at the DCC link its just a matter of attaching the wires from the motor to the decoder and using IRJ's on the turntable track pieces.

Then theres the DCC Bus wiring system mentioned above that I'm lost with.

I'm soldering a wire to each outlet track on the turntable and using droppers whatever they are?

But if I'm happy for the train engine to be "dead" while its on the turntable and the table is turning then I dont need to do any of that right?

If thats the case then its just a matter of connecting the turntable motor to the decoder and I'm good to go?

Or......to make this a whole lot easier, if I want everything to work, sound and lights on the engine whilstt he turntable turns and the turntable to be 100% compatible I may be able to take it to a local retailer to get the job done.

Would they only require the turntable, motor and dcc decoder, anything that needs to be wired such as track sidings I would also have to give them the appopriate pieces of straight track as well?

Does the wiring have to be soldered ato any other part of track on the layout or can I just get this done as a self contained turntable thing?

As mentioned before this is way out o my skillset and I'm not even sure my local guy can do this but at least if I know what I have to give him up front its a start.

[Fishmanoz]

TDJ, I could answer your question but it would take a lot of detail to do so and effectively hijack this thread by being distracting to Storm as he struggles to understand one only method given by Chris in the link.  If you want an answer, ask again in a new topic with an appropriate title please.

 

Storm, not sure why you want to go and by a new power track when it’s a 2 minute job to modify the one you have.  Yours is not different to Chris’s photo, it is his RH photo with the red arrow.  Flip the cover, remove the capacitor and replace the cover.  It will now work for DCC and DC.

 

Have you correctly interpreted the conversion method in Chris’s link?  No, you haven’t. You’ve forgotten the need on the underside of the TT to unplug the wires from the centre of the bridge to the connections on the edge of the bridge near where the inlet track goes.

 

What would a model shop man have to do for you?  Three things.  First - wire the TT motor to the motor outputs (Orange and grey) of a loco decoder.  Second - disconnect the bridge wires as above.  Third - wire together the disconnected bridge wires and the decoder red and black power input wires and add an extension lead to them to go to the track A and B connections on your controller.  That will fully power your TT bridge and motor.

 

What do you have to do?  Use IRJs on your inlet track.  If you don’t mind your outlets being dead when the bridge is not turned to them, that’s all you have to do.  If you want them live all the time (or if any are not dead ends, rather connect back to the layout), you have to use IRJs on them too, then have power connections of the correct polarity to the tracks connected via the IRJs to the outlets.

 

Finally, there is an operational limitation with this method.  If you run a loco right up to the TT on the inlet track such that it has wheels either side of the IRJs, stop it there and rotate the bridge, you will cause a short.  You have to keep locos off/outside the inlet track while you rotate the bridge.

[Chrissaf]

But if I'm happy for the train engine to be "dead" while its on the turntable and the table is turning then I don't need to do any of that right?

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No...not right.

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In DCC, the track (all the track) is always live. The Insulated Rail Joiners (IRJ) are needed to prevent short circuits from being created as the TT turns. But fitting IRJs to the inlet and outlet tracks means that the outlet tracks will not get any power when the TT bridge aligns with those particular outlets. Hence the need for the additional power feeds on each individual track piece (these are called droppers).

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A dropper is just a pair of wires that are soldered to the outside or underside (not the inside) of the track rails that drop through the baseboard to connect to a thicker pair of wires (termed a Bus). The Bus wires go back to the 'Track Output' connections on the controller. Typically, droppers are 7/0.2mm wires and the Bus wires are 32/0.2mm wires. The first figure is the number of strands and the second figure is the diameter of each individual strand. Stranded wires should be used in preference to solid conductors as stranded wires are more reliable and less prone to fatigue induced breakages.

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If you leave the TT bridge rails disconnected, it just won't work at all because you won't be able to drive the loco on and off the TT bridge because the TT bridge rails will always be dead.

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Referring back to the 'How To' link in the earlier thread. As the TT bridge rotates, the polarity of the TT bridge rails reverses. Thus some of the outlet track connections need to be reversed for the 'Full Monty' solution (which I have documented below). Alternatively, you could just use IRJs on the Inlet track piece and let the TT Bridge power the outlets, but any standing locos parked on those outlets will lose sound and lights when the TT bridge moves off them. This is all explained in the linked 'How To'.

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Or......to make this a whole lot easier, if I want everything to work, sound and lights on the engine whilst he turntable turns and the turntable to be 100% compatible I may be able to take it to a local retailer to get the job done.

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The work involved is not the kind of work that can be done 'off-site'. Each installation of a modified for DCC Hornby TT will be unique for your particular layout design. Realistically, the modification has to be done on-site at the time of installation. The polarity of the droppers on the outlet tracks need to be correct for you particular installation. These need to be checked for short circuits as they are fitted.

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With all the good will in the world, an off-site retailer will not appreciate the detail of the custom solution that has been developed and documented by the forum membership and probably make a 'dogs dinner' of it. Which you will struggle even harder to unravel compared to doing it all yourself. This is the reason that I suggested in my earlier reply, that in your particular case where you really don't understand what you are doing, that you might be better off digging deeper into your pocket to purchase a DCC friendly TT.

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Does the wiring have to be soldered to any other part of track on the layout or can I just get this done as a self contained turntable thing?

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The droppers are soldered to the track on the layout side of the IRJs. Thus they are not directly connected to the TT itself. Another reason why asking someone 'off-site' to do it is not practicable.

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Maybe this sketch will help you to visualise it. As I have not seen your track plan, I do not know what TT outlet tracks positions you intend to utilise. So my sketch is just a guide. But what thing my sketch does show clearly, is that the modification work required to make the Hornby TT DCC compatible is performed on the layout and not on the TT itself (apart from the motor control). Again, why it is not practicable to have an off-site third party involved.

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The Brown & Blue are just arbitrary colours I have chosen at random to define the wire termination sequence. The colours have no other significance. The Grey / Orange / Black & Red on the decoder however, are the actual wire colours used as standard on decoders. The connection that is made to your normal track, has to be the same way round as the dropper wires connected to TT inlet track, else you will get a short circuit. The high risk of creating a 'short circuit' is why the work needs to be carried out methodically in sequence (on-site) and tested for a short as each pair of droppers are added.

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To see a bigger version of my sketch, right click it and choose either a 'view' or 'save' option....subject to which browser you use.

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Fishy posted whilst I was busy creating my reply. The sketch took about an hour to draw.

[Fishmanoz]

If you refer back to my post added at the bottom of page 1 just before Chris added his, then Chris’s diagram above illustrates perfectly what I’ve said.  And mine describes simply the only TT things you can get done by your model shop man.  As Chris says, everything else has to be done at your place on the layout outside the TT.

[Chrissaf]

I appreciate there is an official Hornby conversion and a multitude of discussions by members that takes ages to consider in detail and read leading to one that is favoured.

 

But has anybody had a stab at what they believe are the simple pros v cons of the differing methods of DCC conversion that I may read and weigh up?

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The main 'PRO' for the forum derived modification. Is that you can leave the TT pretty much intact as it comes out of the box. Apart from the optional motor conversion to DCC and the disconnection of the inlet track wires. In other words you do not have to rip the TT apart to remove the factory fitted brass contacts on each end of the TT bridge rails (the Hornby documented method). These brass contacts are beneficial to leave in place because they help locate the alignment of the rails as the bridge turns. Once you get your head around the track power reversal issue, the forum solution using IRJs is actually very simplistic. And hopefully, my sketch drawing in my earlier post will make that issue even clearer to understand. And that issue is still present even if the Hornby modification is performed. All that removing the brass contacts is doing is replicating electrically what the forum derived solution using IRJs is doing.

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[St1ngr4y]

I hardly dare mention another alternative which I have found, since I produced the conversion writeup a while back. This alternative would fit in better with the Hornby suggested method of removing the brass contacts at each end of the bridge rails. The method also obviates the need for IRJs at the "layout end" of each inlet trackpiece. My idea is to fit IRJs to each end of each bridge rail, or to be more precise, half of an IRJ at the end of each bridge rail. Take 4 IRJs and cut into two pieces just to one side of the central pillar, like this:-

 

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These are to be fitted to each end of each bridge rail. It is recommended that each rail should be shortened slightly to accomodate the protruding part of each IRJ. Also, removal of the brass contacts means that the bridge rails can slide out of position, so should be carefully aligned with two inlet trackpieces with the IRJs in place, and then fixed in position with some adhesive. 

 

The purpose of these IRJs is simply to prevent a short circuit when the bridge is rotating. It allows each inlet trackpiece to be "live".

 

Ray

[TrainDriverJ]

Fishmanoz. Point taken. Bit thoughtless of me really. I apologise.

 

Thanks Chris for the reply anyway. I’ve just been and bought one. It was actually about the brass contacts that I was most interested in as there is 1 conversion with and one without. I had noted that they sometimes catch on the rails and may cause damage but with what you say then ……..

 

I’ll now go and read all the old posts rather than make any more intercepts of this post. If you think this may be a new interesting line of discussion perhaps the new comments could be moved?

 

Thanks.

[Fishmanoz]

Just to summarise, the problem with this TT is that it has a quite fundamental design flaw as it comes out of the box - when the bridge is aligned to a track, bridge rail A and track rail A connect to each other, and similarly with bridge and track rails B.  But as soon as you rotate the bridge, bridge rail A contacts track rail B, or vice versa, and you have a short.  You can’t avoid it as built because bridge power comes directly from inlet track power via the brass contacts under the inlet track. 

 

How does it work at all then?  For DC it relies on all the locos on the TT track circuit being stopped when you rotate the bridge.  That means no volts on the track and bridge at the time the cross-contact occurs.  But it will cause a short even on DC if you run a loco at the same time as you rotate the bridge.  It’s fatal all the time on DCC as the track is always live even with all locos stopped and any rotation of the bridge causes the short.

 

The only way to fix this problem is to isolate (or break the connection between) the bridge rails from the track.  Within the forum pages, I’m aware of 5 different methods for doing this.  They are: the Hornby method of removing the contacts at the end of the bridge rails; putting electrical tape under the contacts (yes, this worked for someone a few years back); the Blackbird gapped inlet track (cut the inlet track rails between the brass contacts and the bridge and rejoin them with IRJs or similar, then also use IRJs on any powered outlets); the Ray method of separated bridge power plus IRJs; and the 2nd Ray method of half IRJs at the ends of the bridge rails. 

 

Then finally there is a sixth method.  Don’t buy this TT at all, get a real one.

 

Take your pick.

[96RAF]

My homemade TT doesn’t use IRJs or contact strips so I have never seen any off these problems. Ignorance is bliss I suppose.

The inlet/outlet and bridge tracks are DCC and bridge polarity is controlled by a centre OFF DPDT switch, but an RLM could be used in lieu. I have included polarity indicator leds to aid bridge configuration switching.

Rotation is DC and controlled by a (ON)-OFF-(ON) switch. TT drive not shown below.

It is wired thus...

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The jack plug/socket method of getting power to the bridge is different to most other TTs but in principle it is electrically much the same as wiper rings, so may help folk understand the need to modify the Hornby TT.

 

[Storm68]

Thanks guys, that made a lot more sense. I appreciate everyone taking the time to help me out.

As for cost, I've only found one with a dcc decoder inbuilt at 4 times the price and a hole needing to be cut.

My table has a lot of cross beams so there wont be any cutting, my budget doesnt justify spending a minimum of $400+AUD on a better turntable.

I'm sure we're talking the W brand here.

I can do this for less than half the price of this, I just have to get my head around it.

Or I just bite the bullet and sell a kidney and buy a W.

[Fishmanoz]

Good solution there, bite the bullet while the kidney’s being removed and save on an anesthetist!  I imagine there are lots of layouts with a TT and one kidney.

[Storm68]

Just out of curiosity, instead of soldering a wires to each siding track piece on the turntable you can buy track joiners with the wires already attached.

You could use IRJ's at one end that meets the turntable and at the other end of the same tack piece use a pair of these joiners to power the track running to the DCC Bus?

[Chrissaf]

Just out of curiosity, instead of soldering a wires to each siding track piece on the turntable can you buy track joiners with the wires already attached.

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Yes you can, but they are disliked by many as lacking long term reliability. The purpose of the track joiners is to allow heat and cold expansion and contraction. Over time, this can result in the electrical continuity reliability being compromised as the joiners loosen. This is why many who implement a full layout Bus wiring system, install droppers on each and every single track piece so that the rail joiners are just relegated to performing physical joining and alignment.

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PECO sell them as part number PL-80 (for Code 100 track). Fitting them to Hornby track may require a small amount of fettling. Be cautious when buying these products as PECO sell similar ones with different part numbers for other 'codes' of track.

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However, the Insulated Rail Joiners ideally need to be placed on the joint where the short TT outlet track joins to the main track siding. This means that the the PL-80 joiners would need to be placed at a track joint that precedes that on the layout.

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In other words, look back at the drawing I added to my earlier post. The droppers that I show connected to rails are very close to the end of a drawn track piece, so it would be that end of the track piece closest to my drawn droppers that would potentially have the PL-80 feeds.

[Lanc]

Hi all,   I seem to have found another solution to using the TT with DCC and without any TT  modification.  However it does utilise an old DC controller alongside my NCE track controller. Due to a restriction of space my TT is at the far end of my loco shed and has been turned through 180 degrees so that the original TT inlet track is now only a short siding leading only to buffer stop and the contacts it has are now unused.. As a result of this rotation, power to the turntable bridge comes from either one or indeed all of the other TT tracks provided they have a source of DCC power. Power to the bridge is then only from the track it is aligned with. And as either track rail passes over the brass contacts there is no corresponding link to complete a circuit and cause a short. There is however one snag, and that is with sound locos which shut off as soon as the track begins to rotate and contact is lost until aligned with the next track and sounds can be switched back on before moving off, a minor problem for me but others may find it irritating.    Rotation of the TT is as I have said DC from an old Hornby controller which has zero in the centre and therefore rotating the dial clockwise rotates the turntable clockwise and equally the opposite when anti-clockwise is applied, speed is therefore dependent on how much power is applied but is easily rotated in  “ realtime” scale speed.