basic question on R070 turntable

[steve_gleghorn]

Before I get into the complexity ( and butchery)of DCC running i have just tried to see if the turntable will turn at all. All I get is a buzzing noise but no rotation from the motor when i directly connect to the track power

 

Is this a fault with the turntable or with my niave assumtion that power will at least turn the motor?

 

When i connect with a c990 and r965 controller it buzzes for just a second on powerup

 

Help! Im nearly 70 and losing more of my hair!!

[Chrissaf]

The electric motor used by the R070 is a DC motor, so Yes it should turn when connected to a C990 & R965 power supply / controller combination.

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All I get is a buzzing noise but no rotation from the motor when i directly connect to the track power

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Do NOT power the TT motor directly from the track if your track is DCC. To do so will definitely cause the DC motor to buzz and not turn, and if left connected too long, to then burn out. To use DCC track power for the TT drive motor you must include a DCC Decoder (such as the R8249) between the track and the TT motor.

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Assuming you are using the C990/R965 combination to power your TT motor and you say it buzzes, do you mean the motor buzzes or the power supply/controller buzzes.This is an important distinction to make in your next reply. If the controller and/or power supply is buzzing, then that could indicate that your TT has a short circuit on the motor connection path. If the motor is buzzing, then that would indicate that there is an electrical current path through the motor, but the physical mechanism has jammed up preventing the motor turning.

 

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[steve_gleghorn]

The electric motor used by the R070 is a DC motor, so Yes it should turn when connected to a C990 & R965 power supply / controller combination.

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All I get is a buzzing noise but no rotation from the motor when i directly connect to the track power

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Do NOT power the TT motor directly from the track if your track is DCC. To do so will definitely cause the DC motor to buzz and not turn, and if left connected too long, to then burn out. To use DCC track power for the TT drive motor you must include a DCC Decoder (such as the R8249) between the track and the TT motor.

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Assuming you are using the C990/R965 combination to power your TT motor and you say it buzzes, do you mean the motor buzzes or the power supply/controller buzzes.This is an important distinction to make in your next reply. If the controller and/or power supply is buzzing, then that could indicate that your TT has a short circuit on the motor connection path. If the motor is buzzing, then that would indicate that there is an electrical current path through the motor, but the physical mechanism has jammed up preventing the motor turning.

 

.That was fast!! Thanks

 

Ive tested the pwer supply and controller and they seem to be working. I assume ( yes I know!) that the 2 different outputs are one for variable, that the one I want, and one for straight 16v (2pin)

 

You said

This is an important distinction to make in your next reply. If the controller and/or power supply is buzzing, then that could indicate that your TT has a short circuit on the motor connection path. If the motor is buzzing, then that would indicate that there is an electrical current path through the motor, but the physical mechanism has jammed up preventing the motor turning

The buzzing seems to be coming from the centre of the turntable; the motors not turning at all. How can I get to the turntable mechanism without fear of springs, cogs etc flying around the room which is in such a mess it would be impossible to find any small bits! Do I just undo the top centre screw in the middle of the table?

 

 

[Fishmanoz]

Hi steve, for a start, please don't use the blue button in a post to reply to it, all you get is a mess as you may have noticed.  Instead, go to the bottom of the page and use the text box and the green Reply button as Chris and now I have done.

 

You certainly appear to have something seriously wrong.  If you have just purchased it, send it back under warranty.

[steve_gleghorn]

 Thank you. Sorry about the blue button..Im used to other forums.

I have now tested the motor without cogs! and it is working well. I guess something was jammed in the mechanism ( however simple it may be), and it seems to have sorted itself. The TT works in both directions and is speed contrllable. I intend not to DCC it but use isolating rails on all "track outlets"  and use the controller. I will dcc the outlet rails in due course

 

I have a spare loop module if I need to do that...but that no doubt is for another day after my hair has grown a little!!

 

Thank you both for your input. Most supportive

[steve_gleghorn]

Now that its rotating ok I have isolated all the in/out rails and of course the loco now stops as soon as it comes to the isolators; Do I now connect DCC to the 2 terminals in trhe centre underneath the TT or is that just too simple

I have to say this is a very expensive poor product from Hornby! 

[steve_gleghorn]

I'm now moving on to DCC as this turntable is pretty useless as it is ( what a poor product)

Do I connect DCC feed to the two contacts under the TT in the middle?

 

If this TT was given to a 7 year old  for Xmas rather than 70 I'm thinking there would be even more tears!

[Yelrow]

Steve, i run one of these TTs quite happily from  Dc, on my DC layout. It works well, little wrong with it as a product.  There are better tts for DCC operation, but expensive. You have to modify this one, before you can use on DCC. If you look up on previous posts, there are those, who have modified them. For my DCC, i use a Frateschi, with suitable fitted decoder, working through Railmaster/Elite. There is a very good Brian Lambert site on the internet that fully covers the A to Z on turntables. No doubt , another poster will give you the link. john

[Chrissaf]

John, your wish is my command.......abracadabra........well we are approaching Panto season.

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http://www.brian-lambert.co.uk/DCC%202.html#Turntables

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PS - Well would you believe it "abracadabra" was recognised in spell checker.

[Chrissaf]

The main issue that I see modifying the Hornby R070 for DCC is because it is originally a DC TT, it uses a 'Split Ring' design. This means that there are some dead spots as the TT turns where a DCC Sound Loco will lose sound (if no stay-alive is fitted) and/or lose directional lights. For DCC (in my humble opinion) a 'Slip Ring' design in conjunction with an RLM is the better option. The 'Slip Ring' design is contiguous and has no breaks in electrical continuity throughout the 360 degree rotation.

[Yelrow]

merci beaucoup, hence the Frateschi. john

[Fishmanoz]

There are 2 main issues with converting this TT for DCC operation.  The first is whether to operate the motor DCC via a loco decoder or DC directly as you've already done.  This is quite independent of the second issue with needing to isolate the input and outlet tracks to avoid shorts.  Rather than repeat the options for isolation, there is already more content on it in the forums than you can jump over.  Try some searches on R070, turntable and TT and you can find all of it.  Start your searches using the term in the thread titles, then do it on thread content, it's all there. The chances are Chris may even do some searches for you and post the links.

[Chrissaf]

Not this time Fishy, this is one of those topics were there is so much content on the forum, that it is hard to pick any really informative posts out of the masses of background dross.

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Other than Brians website (linked in previous reply) most of the content on here relating to TTs has limited clarity in them (IMHO). Too many digressions in the threads.

[St1ngr4y]

Hi Steve,

You are quite correct. Unplug the wire which leads from the underside of one of the inlet roads to the centre of the TT and connect this to your main DCC circuit. However, it matters which way around the wires are connected - you have a 50-50 chance of getting it right  😀 On my layout, the TT has only one road leading to the main layout, and I ensure that the DCC polarity of the TT rails is the same as the inlet track from the main layout. If you have isolated ALL of the in/out roads, this means you can have power to their sidings continuously, even when the TT bridge isn't aligned to them, but you need to connect your main DCC circuit to each of these sidings, and you must get the polarity right for these too i.e. the same polarity as the TT rails when the bridge is aligned to that siding. Also, you need to have left in place the brass contacts which protrude from the undersides of each end of the TT rails. These are needed to pass current from the TT rails to the in/out rails.

Ray

[Chrissaf]

I've never seen a Hornby R070 in the flesh, but there should be two connections somewhere underneath that provide connectivity to the 'Split Rings'. It is these 'Split Rings' that need to be connected to your DCC track supply.

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If you have a multi-meter set to ohms resistance, then if you have identified the correct wire termination positions. Then you should get a near 0 reading between each wire termination point and one or other of the physical rails on the rotating bridge.

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EDIT: Ray got in just ahead of me with a fuller description whilst I was typing.

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PS - As far as I know I don't think the Hornby R070 design has been changed or updated in years. Again another example of Hornby not moving forward with the times and producing proper DCC Ready accessories to go with the DCC locos. To my mind the Hornby R070 doesn't look very realistic either, far too much 'toy like' for my taste.

[Fishmanoz]

Starting with the standard TT configuration, track voltage gets to the bridge via 2 contacts under the inlet track.  Then it gets to the outlet tracks via the brass contacts under the ends of the bridge rails.

 

This configuration works fine for DC, including the reverse polarity on half the outlets due to the split ring design.  However, it only works because the locos are stationary on the bridge while it is rotating so there is no voltage to the bridge.  If there were, as soon as you rotated 16.5mm track A on the bridge would be in contact with track B on the inlet track or vice versa and you would get a short.

 

This is then the fundamental DCC problem as there is track power the whole time and it shorts out as soon as you start to rotate the bridge.  There are 2 solutions.  You either:

 

-  remove or isolate the bridge contacts (one person worked his by putting electrical tape  on the contacts) and then have to power all of the outlets with correct phase; or

 

-  you put a gap in both inlet track rails between the brass contacts under them and the bridge (a forum member used to make and sell such gapped inlet tracks but no longer) and then also gap any outlet tracks that are powered from any source.

 

And that Chris is the sum total of the contributions from those myriad posts.

[RDS]

... that it is hard to pick any really informative posts ...

 

Have a look at my posts on the Hornby Turntable.  They were based on my own experience of converting that particular turntable to DCC.  (I have since sold it, because I decided I didn't want a Turntable but it worked well when I had it).

[Chrissaf]

RDS, it is easier for you to find a historic old post of your own, compared to others doing it. Perhaps when you get a moment you would search your old post and add a direct link to it back here.

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TA

[St1ngr4y]

Fishy,

There is no need to GAP the inlet rails - all you do is use IRJs to connect them to the next piece of track.

Ray

[Fishmanoz]

Ray, IRJs on the inlet track cannot be between the brass pickups, which are under the inlet track rails and power the bridge, and the bridge itself.  Therefore, this won't work if you use the standard inlet track arrangement.  You could move the bridge power point of course (would have to beyond the IRJs) but then you run the risk of a loco bridging across them and you are back to having a short as soon as the bridge rotates.

 

Like Chris I've never actually seen the TT but I still believe the gapped inlet track to be the most elegant solution to DCC conversion for it.  Gapping the tracks, fitting some insulating material so they can't reconnect and then ensuring they stay in position is the only hard bit.  And for someone who then doesn't connect any of the outlets back to the layout, it's all that has to be done. 

[St1ngr4y]

Hi Fishy,

If you look underneath the TT, you will see a pair of wires leading from the "brass connectors under the inlet track" to the centre of the TT where they connect to the bridge. They are connected to the brass connectors by "spade" connectors. All that needs to be done is to unplug these spades and connect them directly to the main DCC bus. The brass connectors under the inlet track then become redundant. The IRJs are placed on the outside of each in/out trackpiece (including the main inlet track) to isolate them from their adjoining trackpieces.

Ray

[RDS]

... search your old post and add a direct link to it back here ...

 

This is not the Thread I was thinking of but it shows the process I went through with lots of help from the regulars.  It is more of a saga than anything else!

https://www.hornby.com/uk-en/forum/post/view/topic_id/6205/?p=1

 

[Chrissaf]

RDS, your link above appears to be broken, it doesn't take me where I was expecting it to take me in the forum.

[Fishmanoz]

Ray, yes, I understand your method but it still suffers from the possibility of a loco bridging across the IRJs and again shorting out when the bridge rotates.

 

And with your outlets, you only need to isolate them if they connect back to the layout, otherwise the bridge can power them when it is turned to them.  That's only a problem if you have sound locos you want to operate when the bridge turns away from their outlet.  

[RDS]

Sorry, I will try again.

https://www.hornby.com/uk-en/forum/hornby-turntable---r070/

 

This is the one.