Adding TTS to an old 3 pole ringfield based HST

[ColinB]

Has anyone ever fitted a TTS decoder into an old Hornby Rigfield based loco with a 3 pole motor? I am converting my old HST to DCC, adding extra pickups, an 8 pin socket and front and back Leds. I would like to fit the TTS sound decoder. I have done all the current measurements for maximum running current and stall current, and the values are within specification for the TTS decoder. So has anyone done it, I can sit for ever trying to work out if it will be OK, but it is much better if someone has had the practical experience.

[96RAF]

See here

http://www.halton96th.org.uk/article10.html

 

This article goes on to replace the ringfield with a DVD motor

http://www.halton96th.org.uk/article11.html

[ColinB]

Great, thank you. So it can be done. 

[2e0dtoeric]

I don't have the inclination to read all the conversion details,so this might be mentioned -

BUT

-

You MUST ensure that the motor is electrically isolated from the chassis, as Ringfields use the chassis as a wire! You must also ensure that the decoder is totally insulated from contact with any metal bits of bodywork - or they go phut!

[96RAF]

As Eric says once you have disconnected the motor wires, check the brushes on your particular motor are not in continuity with the wheels. If so you must find that electrical path, usually by way of a metal screw on the left hand brush taking continuity from the motor housing. A nylon screw in lieu will sort that.

[ColinB]

Yes, I checked that. The ringfield in my HST is the type where the brush holders are rivetted to the plastic end plate rather than the screw type. 

[2e0dtoeric]

In that case, Colin, you might find that one of the brush holders is pressed down against a raised spike on the chassis - so is NOT electrically isolated.

You need to - either remove the spike, or put some plastic insulation between it and the brush, but if you do that, it might chafe through in time anyway, and kill the decoder.

[Ruffnut Thorston]

There is also a type of Ringfield motor that has a 'bridge wire' connected to the Left Hand Brush holder, and the motor block.

 

This needs to be removed. Simply plugs into place, no cutting required.

 

Also check that there is not the metal pin as well though!

 

As said...remove pin by cutting off, and put some plastic into the hole in the faceplate, behind the metal of the brush holder, where the pin contact was...

[ColinB]

Yes, checked all that. My one has a separate earth lead so remove that and see if it still works, which is what I did. You can also do it if you have added extra pickups to the loco on the other bogie, if you turn them round, and just connect them to the motor does it still work? Did the same test on my old class 90, and it shorted the controller out, which I found out was due to the self tapper that screws into the chassis. Thank you for the help though.

[Ruffnut Thorston]

Yes, that 'earth wire' is the 'bridge wire' connected to the Left Hand Brush holder, and the motor block.

 

Good to know you are on top of things. 😀

[ColinB]

Mind you after my experience with my relatively new Hornby class 66 loco running a TTS module, that just failed, I am going off TTS completely. It is not the first failure either, I had had two where the sound didn't work from new ( fortunately replaced under warranty) and now I worry about the long term reliability of the other TTS modules I have fitted.

[bluesman]

I have fitted a dcc chip to an HST with Ringfield type motor I have done this a few times before also at the same time I fitted chips to an old Hornby 08 class 37 and class 29 all the models where tested new brushes fitted, the problem I now have is they will not work on there own they just jerk on the track but if I put another loco on the track both work ok. the only thing I have done is have the two select units updated by Hornby all other locos with chips fitted before the upgrade are working correctly. Has any body had a similer fault ?

[96RAF]

I would reset each errant decoder and readdress them. i would also reset all of the controllers. You then have all your ducks in arow and can start fault investigation if still required from a known baseline.

 

You say both Selects. Presumably you are using one as a master and the other as a Walkabout linked via the correct Xpressnet cable (there are two types - right and wrong) and the slave Select is not powered apart from the Xpressnet cable.

[ColinB]

I had this fault when I fitted a DCC decoder to my ringfield based class 86, although it worked perfectly on DC. In the end I found that the ringfield was a bit stiff, once I had freed it off it worked perfectly. It seemed when running in DC there was more power to drive the motor. I was also advised to add "keep alive" as with my ringfield motor the loco doesn't have pickups on all wheels. I used a high current Zimo module as I was worried about the current. As it was a class 86 there was loads of room to add capacitors so that is what I did, it runs perfectly now. Perhaps you need to run the new brushes in on DC.