R070 Hornby Turn-table to DCC including images

[PJ_model_trains]

Although there have already been a number of posts for the Hornby Turn-Table R070, this one has been started as a new thread for the following reasons.

 

1 - It includes images of the top side and underside of the turn-table so it is clearer to see what is being discussed.

2 - There have been lots of talk of what is best to convert the R070 turn table to DCC, using words like butchery etc.

 

As mentioned on a previous thread, I have tread many of the previous threads ideas and for me, the one that seems the best is the method Ray has used. So having discussed this with Ray, I add the images at the start of the thread, so they are easy to reference by all at a later time, Ray will then follow with his idea and the way he has converted his turn-table on his layout. It would be most helpful, to all members, now and in the future, if we let Ray add his post here before before further discussions and ideas are added. 

 

Plan view of Turn-Table R070

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Underside of the turn-table

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Close up of the centre of the turn table - view to underside

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Underside showing wires that lead from centre of turn-tabe to the edge of it.

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We look forward to Ray's details of how he converted the turn-table on his layout for DCC and how he configured it in RM.

 

Hopefully to information will be helpful to other members in the future.

[PJ_model_trains]

Thank you for your patience.

 

Ray has requested more images from me so as to be clear regarding the information which is added here as guidance, especially regarding what is to be removed and changed. I will add these images as soon as possible.

[St1ngr4y]

These notes are an account of how I installed a R070 turntable on my DCC layout. I know there are variations to this method, so I have tried as much as possible to provide the reasons why I chose this way.

 

Installation of a Hornby Turntable R070 on a DCC Layout

1.     The Decoder

This should be any locomotive decoder, for example, a Hornby R8249. Unfortunately, the turntable is not DCC-ready, so there is no socket into which the decoder can be plugged. Instead, the 8-pin plug on the decoder needs to be removed by cutting all of the wires near the plug. Unless it is planned to have lighting, for instance, in the control cabin of the turntable, then only 4 of the wires are needed to operate the turntable itself – orange & grey, which must be connected to the turntable motor leads, and red & black, which need to be connected to the DCC supply. The remaining wires from the decoder can be cut off near the decoder end if they are not going to be used for lighting or any other purpose. A decision needs to be made as to where to locate the decoder for operational use. I have seen forum posts by users saying they have managed to squeeze the decoder into the small control hut on the turntable, which already houses the turntable motor. There is nothing wrong with this. However, I chose to house the decoder for my turntable inside a nearby signal box. The reason for this was simple – to cater for the possible need to re-program the decoder in the future. Initially, the only CV which must be changed is its address in CV1. This can be done before physically installing the turntable on the layout. Having connected the orange & grey wires to the turntable motor, simply connect the red & black leads from the decoder to the programming terminals of the controller, then program its address CV just as if it were a locomotive on the programming track. However, if, at a later date, the decoder somehow loses its address and resets it back to the factory default of 003, then it may not be so easy to connect the decoder to the controller programming terminals. So, underneath my “nearby signal box”, I have the red & black wires from the decoder plugged into a bit of terminal block, then two wires from there to the DCC bus. If re-programming of the decoder is necessary, all that is necessary is to lift the signal box, disconnect the bus wires from the terminal block, and replace them with twin flex long enough to reach the controller’s programming terminals.

 

2.     Power to the Bridge

As manufactured, the bridge of the turntable gets its power supply by way of two wires on the underside leading from the centre to two brass contacts located under one of the inlet roads. These two wires are held in place on the underside of the turntable by a strip of 3M black tape. With this method, these brass contacts are not used. The wires should be disconnected from the brass contacts and connected directly to the DCC bus. When my turntable was bought, the connection to the brass connectors was via a “spade” connector on each wire. These spades simply slid on to the brass connectors on the underside of the turntable, and could be easily unplugged. However, having seen PJs close-up picture of this connection on his new turntable, it seems that the connection is now covered by a bit of heat-shrink insulation, which needs to be removed before the spade connector can be unplugged.

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Having disconnected the two wires from the brass contacts, the wires should be passed under the baseboard through a hole, to be connected to the DCC bus. The nearer this hole can be placed to the centre of the turntable, the more of the wires will be available underneath the baseboard for connection to the DCC supply. It will probably be necessary to remove the 3M black tape to achieve this. When connection is made to the DCC supply, the polarity of the rails on the bridge needs to be the same as the inlet road from the main layout, when the bridge is aligned to that inlet. A multimeter is useful to check that the wires have been attached to the DCC supply the correct way around.

 

3.     The Inlet Trackpieces

For each inlet trackpiece used, its metal rail joiner should be replaced by an insulating rail joiner (IRJ). The metal RJ of the adjoining section of track should also be replaced by an IRJ. The reason for doing this is to avoid a short circuit when the bridge is rotating, when a bridge rail makes contact momentarily with the “wrong” rail of an inlet track.

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These IRJs are vital for the inlet road leading to the main circuit. However, for those inlet tracks which only lead to dead-end sidings, then optionally they can be left as metal RJs, so that the whole siding will receive its DCC power when, and only when, the bridge is aligned to that siding. Doing it this way, of course, means that locos will not be able to be moved or use sound/lights on such sidings when the bridge is not aligned. If you do want these things, then not only is it necessary to use IRJs, but the sidings themselves need to be given their own DCC supply by means of droppers to the DCC bus. Again, these DCC supply wires need to be connected to each siding so as to reflect the DCC polarity of the turntable bridge when it is aligned with that siding.

 

 My thanks to PJ for providing the photos.

 

Ray

[Chrissaf]

So, underneath my “nearby signal box”, I have the orange & grey wires from the decoder plugged into a bit of terminal block, then two wires from there to the DCC bus.

.

Ray, did you mean the Red & Black wires (Track right / left) rather than the Orange & Grey (motor right / left).

.

If you did, then you could ask Adam forum@hornby.com to amend the text for you. The Community Moderators cannot amend posted text.

[Silver Shiney]

Silly Question of the Day No 1:

 

I understand the need for rail A on the baseboard to be the same polarity as rail A on the turntable (and B to B), but happens when the turntable is rotated 180 degrees, as rail B will then be in contact with rail A.

 

Number 2: As there are no brass contacts on any of the exit roads, and there's a small clearance gap between the A/B rails and the track leading to the siding(s), how do those sidings get power if not connected to the bus?

 

As you can see, I am a total numpty when it comes this stuff :-(

[St1ngr4y]

Hi,

Question 1 - there is a point during the rotation of the turntable where the polarity of the bridge rails switches. The bridge rotates through this position and momentarily the bridge rails are dead. So if you have a loco with sound or lights on the bridge at the time, the lights and sound go off for a second or two. In this picture the white lines show the position of the bridge when polarity switches:-

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Question 2 - there are brass contacts under each end of the bridge rails which make contact with the rails of each inlet track when the bridge reaches them. The choice for dead end sidings is either to leave metal rail joiners on the other end of the inlet track piece, so that the whole siding gets its power when, and only when the bridge is aligned, or, to use IRJs and provide separate constant power to each siding via droppers to the bus.

Ray

[PJ_model_trains]

Excellent Ray, thank you.

 

@Silver_Shiney 

 

You can see the brass contacts on the edge of the bridge, where the bridge joins with the input track,or output lanes on the following images above.

 

1 - The first image in the first post

2 - The second image in Ray's (The Inlet track pieces) The track is laid on top of them.

 

My choice is to have IRJ's on ALL lanes used, in and out. Except for the momentary loss of power when the TT passes the polarity change at all other times the tracks will remain live. Bridge powered by DCC droppers, ALL lanes powered with DCC droppers. (care with polarity to the out lanes where polarity changes at the bridge)

 

For me I want to keep sound and lights working as much as possible, I may have a loco in an engine shed or other lane where I want the engines to start from cold, etc.

 

@St1ngr4y 

 

I understand you are going to add another thread in the RM forum, for setting up the TT to work in RM, excellent idea, when you do can you add a link from this to the new thread in the RM forum and visa versa. Thank you.

[Fishmanoz]

Good explanation Ray, but just one clarification on terminology in case anyone is confused.  Ray has called all of the tracks connected to the TT inlet tracks.  Hornby's terminology is there is only one inlet track, the one with the brass connectors under it (that Ray removed), all the others are called outlet tracks.  Note Silver Shiny talks about outlet tracks in his post and what I've said above explains what he means. 

 

It it should also be noted that there is an operational limitation important with this method of conversion.  This comes about because the IRJs are some distance away from the TT being at the other ends of the inlet/outlet tracks.  Consequently, it is possible to drive a loco right up to the TT and so have its wheels bridge the IRJs and reinstate the short when the bridge rotates.  You will need to be aware of this and not drive locos onto the inlet/outlet tracks except when driving on or off the TT.

 

This limitation was avoided by Blackbird using his conversion method.  He left the bridge power intact via the spade connectors to the brass contacts on the inlet track, then "gapped" the rails on the inlet track between those contacts and the bridge end of the track.  This is a somewhat fiddly operation whereby a cut is made in each track, insulation fitted in the gap made and you probably also need to fix the short bits of track to their chairs on the sleepers to stop them coming out.  Doing it this way means that there is little chance of a loco bridging the gaps as they are so close to the TT.  If you don't mind outlet tracks being dead when the TT isn't turned to them, then no further mods are needed.  However, if your outlet tracks are connected back to the layout and hence the DCC bus, or you want your outlets live like PJ for sound, then you have to also gap (or use IRJs with the operational limitation) on all such outlet tracks.  Blackbird used to sell these modified tracks, but no longer.  If you want further explanation of how to do it, his original post describing it is still on the forum and you can search for it, or you can search my older posts as I've put a link to it but more than a year ago.

[PJ_model_trains]

@Fishmanoz

 

I have read carefully how you see the details Ray has put, please allow me to say how I see it, I am not saying which is right or wrong as there are a number of ways to get round the issue.

 

Firstly the bridge, as Ray stated the wires are re-directed direct to the DCC Bus, therefore we can be sure of power to the bridge, with the exception of the small time between polarity difference as it turns.

 

The inlet track, this is from the main layout and has DCC feed to it, providing power right up to the IRJ's, just before the small track inlet rail.

 

The outlet track, here I refer to the lanes outward from the IRJ's, these are live all the time, as is the main layout, if each is connected direct to the DCC Bus, ensuring the correct  polarity to match that of the turn table position subject to its position and manufacture.

 

This just leaves therefore the small sections of track from the TT to the IRJ's inlet and outlet. The sections will be live when the TT is in line with the inlet outlet sections as the track comes into contact with the brass contacts on the end of the TT, but are dead when not in line. I ask myself is this an issue? I cannot see it being an issue, I would not want to run another loco up to the TT when the TT is in use, therefore I would stop an incoming loco before the IRJ's at the small lead in section of track. I would also only move the TT when the loco is fully inside the bridge section. Therefore for the small sections of inlet/outlet to be track as the TT rotates, between the track inlet/outlets is not an issue.

 

Could there be a power issue to the small lengths of track between the TT and the inlet track, or outward lanes, between the bridge and the IRJ's, possibly one may say with use, but this can easily be got round by adding droppers to these small track pieces, a belt and braces approach I think, naturally ensuring the polarity matches with the TT.

[St1ngr4y]

Could there be a power issue to the small lengths of track between the TT and the inlet track, or outward lanes, between the bridge and the IRJ's, possibly one may say with use, but this can easily be got round by adding droppers to these small track pieces, a belt and braces approach I think, naturally ensuring the polarity matches with the TT.

 

Hi PJ,

.I'm afraid you can't add droppers to these small track pieces. They must remian dead while the TT rotates, so that when a bridge rail contacts the wrong rail of one of these track pieces via the under-rail brass contact, you don't get a short circuit.

Ray

[Fishmanoz]

Thank you for your certainty PJ, which I'll take to mean you're sure I'll help, and I will.

 

May I just start again with the TT unmodified operating on DC.  Unmodified, as soon as you rotate the bridge 16.5mm, Track A on the bridge comes into contact with Track B on the inlet track or vice versa.  Not a problem with DC as the loco is stationary on the bridge so volts is zero.  But a problem with DCC as the track is always live, and a short occurs here, as it does for all Track A/B juxtapositions when the bridge rotates past the outlet tracks.

 

The solution is simple - isolate the inlet/outlet tracks from the bridge.  The Hornby method is to remove the contacts at the ends of the bridge rails. Ray's method is to use IRJs on the inlet/outlet tracks at the far end from the TT.  Blackbird's method is to gap the inlet track and outlets if connected to the DCC bus.  Another person some time back put insulation tape under the bridge connectors and that worked for him too.

 

My point above on Ray's is that it is possible to short out the IRJs by driving a loco over them such that it is contacting both sides of the IRJs, so bridging the isolation.  I said you would have to ensure this wouldn't happen by avoiding it when operating.  You said you wouldn't anyway so you will have no problem with Ray's method.

 

However, on your final point, powering the inlet/outlet tracks via droppers to the bus, you most certainly can't do this as you are just reinstating the condition of powered Track A to B and a short when the bridge rotates.  These tracks must only be powered by the bridge when it is turned to them and must otherwise be dead.

[Fishmanoz]

PS to mine above: Ray beat me to posting about not being able to power the inlet/outlet tracks. And I took the longer post route to go back to explain why the inlet/outlets must be unpowered.

[PJ_model_trains]

Could there be a power issue to the small lengths of track between the TT and the inlet track, or outward lanes, between the bridge and the IRJ's, possibly one may say with use, but this can easily be got round by adding droppers to these small track pieces, a belt and braces approach I think, naturally ensuring the polarity matches with the TT.

 

Hi PJ,

.I'm afraid you can't add droppers to these small track pieces. They must remian dead while the TT rotates, so that when a bridge rail contacts the wrong rail of one of these track pieces via the under-rail brass contact, you don't get a short circuit.

Ray

 

Thanks for contacting me off forum Ray, and also for adding the reply above, I couldn't get to do so.

Caring for older relatives is so important.

[PJ_model_trains]

@Fishmanoz

I am aware of the error, Ray contacted me off the forum as he didn't want to add a reply without contacting me first, he is a gentleman. I placed the reply prior to dashing out, to see to an ill 84 year old lady who is let me just say not her self. I hadn't time to come back and correct the statement though I realised the error after Ray pointed it out. I asked him to reply and correct the issue for me before the wolves zoomed in.

 

The forum is going to the dogs, many are upset about various issues, it is the same people every time.

 

Replies to one thread included three, yes three moderators, at that time there was more of them than other members replying!

[Howbi]

Well, that's put an end to this thread........I've read all the recent posts and, for the life of me, cannot find any adverse comment from anybody that would justify PJ's comments in the above post......... 🤔......HB

[Silver Shiney]

Gentlemen 

 

Thank you very much for explaining so clearly

[St1ngr4y]

I have started a follow-on thread in the Railmaster section, detailing aspects of configuration and operation of a turntable in Railmaster.

https://www.hornby.com/uk-en/forum/r070-turntable-configuration-in-railmaster/?p=1

Ray

[Dazzler down under]

Ray, thanks for taking the time to explain all this, i will refer back to this thread when/if i decide to dcc my turntable.

[Silver Shiney]

Well, bullets have finally been bitten and, after a long time standing there looking at the wretched thing, I eventually plucked up the courage to switch on the soldering iron and wire cutters.  Following Ray's superb instructions, I removed the spade terminals from their contacts and soldered droppers to be connected to the power bus at a later date.  Then, after much deliberation regarding where to side the decoder (eventually decided to give the little man who operates the turntable a large shed nearby where he could store his bicycle, with the decoder and connector block inside), I cut off the two Hornby pins and soldered the brown and black leads to the appropriate wires on the decoder, and then the latter's red and black wires to droppers for the power bus.  I configured the address in Railmaster and switched on.

 

That's when disaster struck. 😢

 

When I removed the unit from the box, I didn't realise that the two wire fences were sellotaped to the outside of the inner carton and had bent them.  In order to prevent further damage, I had sellotaped them between the tracks on the turntable.  What I hadn't noticed, when I first tried to operate the turntable, was that one of these had slipped forward proud of the rotating part, and it jammed the whole thing against one of the inlet tracks, breaking two of the plastic tags holding the rail onto the rotating part, and releasing the brass contact strip.

 

I managed to dismantle the whole thing, checked that the gearing wasn't damaged and reassembled it, making sure that the rotating part of the turntable was realigned wth the centre of the inlet/outlet tracks and that the rib on the large cog had the "missing section" underneath the platter (if I can call it that).  I powered up and everything seemed fine until it had almost completed a 180o circuit, when the motor jammed.  All the cogs were still in place, with no obvious damage, and if I remove them altogether, the motor runs okay.

 

Any ideas, please?

[St1ngr4y]

Hi SS,

Sorry to hear about that - bad luck. Sometimes the bridge rails can slide and contact the inlet tracks. Has that happened? If you remove the cogs, and the motor runs ok, what about the bridge - can you rotate that by hand with the cogs removed?

Ray

[Silver Shiney]

Hi Ray

 

(Note to self - learn to use the correct terminology...)

 

The bridge rotates no problem without the cogs. No inlet/outlet tracks are fitted, so that's not the cause.  When I get back home tonight, I will see if there's one particular alignment where the jam occurs.

[96RAF]

Could well be a burr caused by the initial faux-pas.

[Silver Shiney]

Welcome to Fred Karno's circus, where things go from bad to worse.

 

I removed the gears and the bridge rotated freely.  I then tried rotating it using the large cog, and went through several revolutions.  I then refitted the remaining gears and fired the system up.  It was then that I noticed that I'd snagged the wires going from the chip to the eLink, and pulled the red wire off the chip.... 😳  I tried soldering it back on but although the iron gets very hot, it seems to not want to "tin" and it wouldn't melt the tiny solder patch on the chip.

 

Oh well, back to ebay to get a replacement chip. 😢

[Nictor]

Interesting. I have just bought one to convert but I have a question for Hornby. Why on earth have you not made a few alterations and made it DCC ready?  Is it not time for a major upgrade to you accessories some of which date back to the Dublo era. I am in my sixties and this turntable had been around for a bit when I was a lad!

[Fishmanoz]

Deaf ears Nictor, if they'd listened to comments on here it would have been upgraded years ago.