Turntable mod to DCC

[Glosgas]

I know this is going over ground that's already been covered, but I'm a little confused.

I read the instructions to convert the R070 Turn table to DCC and then read some of the posts concerning the modification.

I have a couple of questions:

1. Is the modification described here https://www.hornby.com/uk-en/hornby-dcc/decoder-installation-guides/turntable-conversion everything that needs to be done or is there other work needed; in particular the power to the roating bridge.

2. Why can't an R8247 decoder port be used to control the Turntable under DCC by increasing the dwell time?  The guide for the R8247 does say 'These differing dwell periods may be useful if motorised point motors are used or if lights or motorised accessories are required to be switched on for a period of time.'

 

Thanks in advance.

Steve.

 

[Chrissaf]

1. Is the modification described here https://www.hornby.com/uk-en/hornby-dcc/decoder-installation-guides/turntable-conversion everything that needs to be done.........

Why can't an R8247 decoder port be used to control the Turntable under DCC by increasing the dwell time?

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Re item 1)

The official Hornby guide is not the most optimum or the best engineering solution for the DCC modification. The best forum minds have put together a solution that has broad forum approval and consensus. You can read the full forum guide here, plus some additional supporting threads on the topic:

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R070 Turn Table DCC Modification

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

 

R070 Setting Up configuration in RailMaster

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

 

R070 DCC Conversion – my version with a detailed drawing

https://www.hornby.com/uk-en/forum/post/view/topic_id/27722/?p=2

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Re item 2)

It is possible for you to do what you say....that is use the 'dwell time' adjustment in the R8247 configuration. But the main reason that the R8247 is not recommended to control the R070 after DCC modification is because the output of the R8247 is at full voltage. The output is not adjustable for TT rotation speed. It also cannot rotate the TT in either direction. So even if you are right next to (forward of) the required output track, you have to do a full rotation of the TT bridge to align to it.

.

The recommended decoder to use, is the R8249 loco decoder because being a loco decoder you can control the rotation speed from a slow start standstill. Not only that but being a loco decoder means that you can rotate the TT bridge in either direction to take the shortest path to the destination output track. The R8249 is far more configurable than the R8247.

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[RDS]

I modified one over 5 years ago.  I can't recall the method I used but I do know that I used the Standard Hornby Loco Decoder, the R8249 as mentioned by Chris above.  It worked very well.

 

[Glosgas]

Chrissaf,

 

Thank you very much for that information.

Steve.

[96RAF]

The R8247 acc decoder is also limited on power output 240mA so could be marginal to power a TT motor anyhow, if you had things like lights hanging on the other ports.