A4 TTS decoder speed problem

[Bongsman]

I have bought a pre-owned A4 model no.R2784X with TTS decoder fitted. There is NO problem with the sound. I am using a NCE Powercab to control it set from 1 to 28 steps maximum. Acceleration up to step 27 is fine, with sound increasing accordingly, but at step 28 the loco drops speed to quite slow. Reducing the speed on the controller one step at a time has no affect until step 22 is reached when the loco immediately speeds up again.

Any help would be much appreciated.

John

[96RAF]

TTS decoders work best on 128 speed steps - see the manual.

If you don’t have it then download from here https://www.hornby.com/uk-en/downloads/view/index/cat/50/

 

[Chrissaf]

TTS decoders are designed to work better on 128 speed steps. Since the TTS decoder uses the same CV29 value for both 28 and 128 speed steps. Then I assume that it is your NCE Powercab that is limiting the speed steps to 28. Look in your NCE Powercab manual to see how to invoke 128 speed step mode.

.

Just to be absolutely sure that your TTS decoder has not been changed from 128 speed steps by the previous owner, you can confirm your TTS decoder speed setting by reading the value of CV29 and comparing it to the information provided in this on-line CV29 calculator. You are looking for CV29 Bit 1 to be enabled.

.

Not that it is particularly relevent, but just for your information.

.

The X suffix in R2784X means that a DCC decoder (without sound) is factory fitted. A loco with a TTS decoder factory fitted would have a RxxxxT or RxxxxTTS product code. An XS product code means that a Loksound Sound Decoder is factory fitted. Therefore your X loco must have been upgraded to TTS by the previous owner.

.

TIP: As a newbie poster on the forum, just be aware that the 'Blue Button with the White Arrow' is not a 'Reply to this post' button. If you want to reply to any of the posts, scroll down and write your reply in the reply text box at the bottom of the page and click the Green 'Reply' button.

.

See also – further TIPs on how to get the best user experience from this forum.

https://www.hornby.com/uk-en/forum/tips-on-using-the-forum/

.

EDIT: Rob posted whilst I was still typing my reply.

[Bongsman]

Thanks for the replies.

I have tried the decoder on 128 steps with no change. I have also done a re-set back to the factory settings with the same negative result.

John

[96RAF]

Try resetting your controller.

[Bongsman]

I have run a few other locos, including a couple of TTS, on my NCE Powercab controller with no problems. Do you still advise to reset it ?

[96RAF]

It is a recognised procedure in the manual hence should not do it any harm and will put all its ducks in a row so you know it is at a good starting place.

[creilly81]

Hi John,

Just an initial thought if you are able, could you place the loco on the programming track and read the value of CV7?

Kind Regards

Chris

[Bongsman]

Just to update for future reference.

I phoned Hornby Tech. and was immediately given instructions to solve the problem.

Set CV150 to 1

Set CV151 to 255

Set CV152 to 1      Hey Presto!

 

Chris - In responce to your query CV7 read 009.

Thanks to all who responded to my cry for help. 😆

John

[Chrissaf]

Bongsman,

Thank you for the solution feedback...most useful.

.

Tweaking CVs 150 & 151 have long been reported in posts as solutions for erratic running. I suspect that these solution suggestions were not offered to you on this occasion because your issue description seemed to be describing something different to the normal erratic running posts we see.

[96RAF]

Normally the CV150 regime 2 fix is recommended for Bachmann locos fitted with TTS. It obviously works well with some Hornby models.