Extra wiring to fit manual turntable

[Edward-352557]

Hello all, newby question here with a query about wiring. I’ve set up my tt120 layout using DCC in conjunction with the HM7000 app. The track is powered by a Hornby 15v 4A transformer via the DCC adaptor. I now want to have one of the tracks feed into a manual turntable and then have two small feeder tracks come from the turntable. I’d like to be able to drive a loco onto the turntable but don’t know what wiring or power supply is required. Would I be correct in thinking I cannot use the dc adaptor that came with the set? Would I need to solder a positive and negative wire to each track and feed it into a power supply (advice please). I have a dozen points each fitted with the Dcc turnout clips, so I don’t know how this would affect any new wiring. Any advice gratefully received.

[96RAF]

First - if your track is powered by the 4 amp transformer and connected directly to the track using the adapter cable then there is no DCC involved - forget about DCC. DCC requires the 4 amp transformer to be plugged into an expensive DCC controller like the Select or Elite.

Treat your turntable as DC and have a look at the how to guide for converting a turntable to DCC as it also includes information about use on analogue. There should be no conversion required.

Edit to reflect Fishy’s post following.

[ntpntpntp]

What make is your manual turntable?

There are two main approaches:

1) feed power to the turntable bridge/deck via wiper contacts and concentric rings and let this feed power to the siding/storage tracks via rail contacts which connect the bridge to the surrounding tracks as the bridge lines up with them.

2) feed power to each surrounding track, and allow this power to feed onto the bridge via rail contacts as the bridge lines up with a track.

The problem with (1) is how to handle the reversed rail polarity when you turn the table 180 degrees? It depends on the design of the turntable bridge contacts, as some makes (eg. Peco) incorporate gaps in the concentric ring which feed power to the bridge, and thus the polarity changes as needed. However some turntables don't have such built-in changeover and thus require an external polarity reverser (switch or electronics) in the feed to the bridge.

Method (2) is simple and is I think the approach taken by @Peachy with his Roco turntable, however this does mean the bridge loses power whilst turning which upsets DCC sound fitted locos and causes them to re-start.

TT120 & HMDCC Controlled Roco/Fleischmann 35900 Turntable

[Fishmanoz]

First to repeat what RAF said for the OP and for Nick - there is no DCC whatsoever involved in this setup. It is purely HM7000 Bluetooth controlled by the app and powered by the Hornby 4 Amp DC supply which is also the supply used by DCC controllers Select, eLink and Elite. But no such controllers are present from the OP’s description.

RAF mentions the Hornby TT conversion as having content which may be applicable to this. This thread can be found at https://uk.hornby.com/community/forum/faq-what-are-my-options-for-installing-a-dc-analogue-r070-turntable-on-a-digital-dcc-layout

But remember again, there is no DCC. However, everywhere DCC is mentioned in the FAQ, you can substitute DC for this setup. The critical thing that makes them similar is that, in this setup, the DC power is on all the time, unlike conventional DC when it is only on when the trains are moving. It’s this on all the time feature that means the TT setup needs to be modified as in the FAQ.

Also remember, as this is a manual TT, there is no powering of the motor to turn the TT bridge to consider, it is just the content relating to powering the inlet track, the bridge track and the outlet tracks.

[Edward-352557]

Thanks for these comments. I’ll read through a few times and try to digest them. I’ll do a bit more research and may be back in touch if the wiring haze does not clear😂