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Hornby TTS Class 66 problem


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11 hours ago, scumcat said:

Please help

 

I too have a tts 66 issue. I have  bought the Hornby Tom Moore the loco was run in on dcc and performed well so I fitted it with a TTS chip it ran ok but it juddered on certain parts of my layout. I have since replaced the speaker with one from west wagon works, still a judder, i fitted lights using the illumination models kit and I have attached a stay alive to the tts decoder using strathpeffer junctions YouTube video as a guide. To try to cure the judder but it hasn’t helped. I have also removed the capacitor from the motor bogie. the stay alive works well I know because if you lift it off the track whilst moving the wheels still turn and the lights are illuminated. However today I noticed that the model judders on the parts of track that have droppers on them. This is really strange to me. The wheels are clean the track is clean, I am at a loss. I have been trying to adjust the CV,s but I don’t know what I’m doing and there are loads of posts on various forums with conflicting advice. As I said please help. My controller is the elite, and my short circuits are aided the old fashioned way with a car headlight bulb.

You can adjust the motor settings with a few Cv's but one of the limitations of TTS is that it wont be as smooth as something like a Loksound decoder. When I fitted TTS to a tom moore model I found the performance to be ok, but sometimes I have had to change the settings on TTS decoders, the settings which usually work well are either CV150 to 1 and leave everything else, or if that doesn't work set it back to 0 and then set CV 151 to 255 and CV152 to 1, if that doesn't help or makes it worse then you probably aren't gonna get it any better than it is now, you can set CV8 to 8 if you want to reset it

 

Richard

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On 12/12/2020 at 18:43, RAF96 said:

The car bulb across the rails acting as a noddy short protector may be OK for DC but you would likely find if you ‘scoped the track it corrupts the DCC signal.

Sorry but this was the recommended way of dealing with shorts given to me last year from the technical support guy at dcc concepts. How do you know better than him please?

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On 10/12/2020 at 20:56, scumcat said:

Please help

 

I too have a tts 66 issue. I have  bought the Hornby Tom Moore the loco was run in on dcc and performed well so I fitted it with a TTS chip it ran ok but it juddered on certain parts of my layout. I have since replaced the speaker with one from west wagon works, still a judder, i fitted lights using the illumination models kit and I have attached a stay alive to the tts decoder using strathpeffer junctions YouTube video as a guide. To try to cure the judder but it hasn’t helped. I have also removed the capacitor from the motor bogie. the stay alive works well I know because if you lift it off the track whilst moving the wheels still turn and the lights are illuminated. However today I noticed that the model judders on the parts of track that have droppers on them. This is really strange to me. The wheels are clean the track is clean, I am at a loss. I have been trying to adjust the CV,s but I don’t know what I’m doing and there are loads of posts on various forums with conflicting advice. As I said please help. My controller is the elite, and my short circuits are aided the old fashioned way with a car headlight bulb.

Its likely....the motor algorithm set on the TTS decoder is incorrect, what speed step does the judder occur at? Most juddering I have had is at slow speed, The Hornby 66 uses the same motor as my Limby class 31 and I have had to change the motor algorithm to get reasonable operation, its the same on the 8 pin Bachmann 37s and the super detail class 31s I have fitted and vitrains 37s and 47s.. in fact im yet to find a motor that TTS works perfectly with out of the box.......

 

Try those....

 

 CV3=35, CV4=20, CV150=1, CV153=215, CV154=0. Also, turn off DC running in CV29 

 

Also.....theres an awful lot of conjecture and discussion on a lot of American modelling forums about the use of car bulbs as short protectors....the gist is while they work.....they can allow a short to persist....and whilst at low currents that's fine....at higher currents....a car bulb puts out a tremendous amount of heat.....enough to start a fire!

 

http://www.rr-cirkits.com/Notebook/short.html

 

also....might be worth bearing in mind @RAF96 is a DCC beta tester for a high profile manufacturer. Might be worth reviewing what you have said as its a bit harsh!

 

 

 

 

Edited by pheaton
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37 minutes ago, pheaton said:

Its likely....the motor algorithm set on the TTS decoder is incorrect, what speed step does the judder occur at? Most juddering I have had is at slow speed, The Hornby 66 uses the same motor as my Limby class 31 and I have had to change the motor algorithm to get reasonable operation, its the same on the 8 pin Bachmann 37s and the super detail class 31s I have fitted and vitrains 37s and 47s.. in fact im yet to find a motor that TTS works perfectly with out of the box.......

 

Try those....

 

 CV3=35, CV4=20, CV150=1, CV153=215, CV154=0. Also, turn off DC running in CV29 

 

Also.....theres an awful lot of conjecture and discussion on a lot of American modelling forums about the use of car bulbs as short protectors....the gist is while they work.....they can allow a short to persist....and whilst at low currents that's fine....at higher currents....a car bulb puts out a tremendous amount of heat.....enough to start a fire!

 

http://www.rr-cirkits.com/Notebook/short.html

 

also....might be worth bearing in mind @RAF96 is a DCC beta tester for a high profile manufacturer. Might be worth reviewing what you have said as its a bit harsh!

 

 

 

 

Thank you for your advice. I didn’t mean for my words to be harsh my account is moderated and i am thankful the moderator didn’t think I was being rude. I also know that raf96 is a tester for railmaster but I was genuinely asking what he knew that was different to the advice I was given by a major dcc Manufacturer after I had to contact them after i was having issues with their products. I have been using the car bulb for a year and a half without issue. The bulb gives a very visual indication of the short until it’s cleared. It is placed so not to cause the issues you talk about. I did use a short circuit protector but found it terrible. Cutting out if I ran more than two locos. 

Edited by scumcat
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Don’t fret about throwing rocks at me. I am used to it and take no offence. I can also be wrong as proven many times on here.

 

I suggested that if you scoped the track with a car bulb installed as a short protection it would likely show corruption of the DCC signal. I haven’t tried it myself, but I do know capacitors on their own corrupt the signal, but a snubber comprising a capacitor and a resistor in series damps any spikes without adversely affecting the signal.  

 

A car bulb exhibits odd characteristics as its resistance changes as it heats up and I would expect that change of resistance to affect things DCC, thus it may only kick in when there is a short circuit scenario and at that stage the signal has already been affected.

 

There are folk on here who know electronics inside out and are far better qualified than me to prove these things and I bow to their knowledge. In fact I would like to hear the theory behind it.

 

Edit: I found this interesting article which explains the theory and practice.

http://www.wiringfordcc.com/track.htm

I also found a diagram of a bulb with a polyfuse added which sort of defeats the object of the excercise.

Edited by RAF96
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The poly fuse is there @RAF96 because car bulbs can and sometimes do mask a short from the command station...and the concern is they can draw enough amps to melt wiring if the short were to go un-noticed for long periods, the poly fuse is there to blow should the bulb draw more than 0.9 amps if you are talking about the same diagram I have seen :) 0.9 amps was deemed to be safe enough to leave on for extended periods. 

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  • 2 weeks later...
On 22/12/2020 at 06:30, pheaton said:

Its likely....the motor algorithm set on the TTS decoder is incorrect, what speed step does the judder occur at? Most juddering I have had is at slow speed, The Hornby 66 uses the same motor as my Limby class 31 and I have had to change the motor algorithm to get reasonable operation, its the same on the 8 pin Bachmann 37s and the super detail class 31s I have fitted and vitrains 37s and 47s.. in fact im yet to find a motor that TTS works perfectly with out of the box.......

 

Try those....

 

 CV3=35, CV4=20, CV150=1, CV153=215, CV154=0. Also, turn off DC running in CV29 

 

Also.....theres an awful lot of conjecture and discussion on a lot of American modelling forums about the use of car bulbs as short protectors....the gist is while they work.....they can allow a short to persist....and whilst at low currents that's fine....at higher currents....a car bulb puts out a tremendous amount of heat.....enough to start a fire!

 

http://www.rr-cirkits.com/Notebook/short.html

 

also....might be worth bearing in mind @RAF96 is a DCC beta tester for a high profile manufacturer. Might be worth reviewing what you have said as its a bit harsh!

 

 

 

 

Was shuffling around some of my TTS class 66 decoders today, installing them in two late model Bacchy 66s (Colas 66846 and DBC 66117).  With the former I ran into problems with low speed juddering and my usual adjustment of the CV150 algorythm dod not sort it.   Then tried Pheaton’s extensive lost of CV changes as outlined above, result: running as sweet as a nut...........So thanks Pheaton. Superb advice.

 

to illustrate the sometimes random nature of DCC, the identical TTS decoder when straight into 66117 with no adjustments required, running smoothly.

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5 hours ago, Johnfromoz said:

 

 

to illustrate the sometimes random nature of DCC, the identical TTS decoder when straight into 66117 with no adjustments required, running smoothly.

The variability is in the locomotives motor, its condition/state of service,  characteristics and the drive train. 

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Change Cv150 to value 1 using the Elite - Menu - loco - direct - cv - input 150, input value 1.

all done on the programming track of course.

All the rest of your fault diagnosis has no effect on motor control.

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