Hardwired class 47 either runs at full speed or not at all

[atticus -1209443]

I've recently purchased a class 47 from a well know auction site. In the forwards direction it runs perfectly, with smooth slow speed control. The issue comes when I try to run it in reverse. Until I twist the dial to ~25%, nothing happens. From this point onwards it proceeds immediately at full tilt.

The model is R2289B, with a ringfield motor.

Any ideas what the cause may be?

[Chrissaf]

You have posted this in the 'Hornby DCC' forum and used the term 'Hardwired'. Thus the inference is that this is a Digital DCC conversion of a Ringfield motored loco.

1. Can you say what decoder is fitted?
2. What controller are you using?

[atticus -1209443]

Hi, thanks for replying so quickly.

I'm using the select controller.

As to the decoder, I'm afraid it came in the loco when I bought it, so I can't say much about that, but it doesn't appear to be the Hornby one

[96RAF]

I would suggest the decoder H bridge is compromised.

One thing you could try ( only if your Select is at the latest revision) is to reset the decoder by writing value 8 to Cv8.

Then set the value of Cv29 to disable DC running.

You can disable DC running when you reset your Select but this does not disable it in a decoder so you have to do both controller and decoder.

[atticus -1209443]

I don't think my select is the latest version, so do you recommend I go to a local model shop who may have a fancier controller?

[Chrissaf]

Upgrading your current Select firmware would be a much more cost effective solution.

The current installed firmware is displayed as the very first number to briefly appear on the Select screen as it is being powered up. Expect to see a number between 10 and 20. At the time of writing, the latest version is 1.6 [16] or 2.0 [20] - both the same. These latest versions completely transform the user experience of the Select controller and add the ability to write (not read) all CVs up to CV255. As well as access to the full F0 - F28 range of functions.

The upgrade charge is typically £15 plus your sending postage costs. You need to get a 'returns number' from Hornby Customer Services - see 'Contact Us' link at the very bottom of the page.

If you do arrange to get your Select firmware upgraded, then you will need both the Select version 1.5 full manual and the version 1.6 addendum manual. As the operation of your Select (how to use it) will be completely different in certain areas of operation compared to your current firmware version.

You can download these two manual PDFs from here:

R8213 Select DCC Controller – Hornby Support

and here

R8213 Select DCC Controller - Version 1.6 and 2.0 addendum – Hornby Support

If nothing appears to happen, check your nominated browser download folder for the files as they can download silently in the background.

[ColinB]

I am wondering if DCC decoder is damaged and is thinking the DCC signal is DC. Trouble is it is not that easy to check as the decoder is hardwired. If you do find there is a fault with the DCC decoder, when you replace it, put an 8 pin socket in. There is plenty of room in these locos for a socket, then that gives you the option of changing between a DCC decoder and a DC header when you have a fault.