TTS decoder issue

[Rilo]

Good afternoon,

 

I have recently purchased the Hornby Britannia class - Anzac, all working well with the standard 8 pin decoder. 

I then decided to fit a TTS sound decoder to complete such a beautiful loco, all was well until two weeks after fitting, which is when the loco stopped responding, no sound or movement at all, after a few hours trying to troubleshoot, I decided to try the decoder in a different loco, and found it to be dead. The loco also still runs perfectly fine on with a standard chip inserted.

 

After contacting the retailer, they agreed to exchange it, however when the new one arrived, this TTS decoder didn't make any sound and only moved slowly in the reverse position no matter how much I turned the power control unit. I took the chip out and placed the standard 8 pin back in and the loco is working fine again.

 

So my question is: is it just plain bad luck that two decoders do not work in a row, or is the issue something else? 

 

My Set Up:

Hornby select unit with standard 1amp power supply. track connection is the green button one.

10ft X 6ft single track line with double track at station and sidings

total of 6 dcc fitted locos on the track (not all operating at once) all working fine with decoders from Hornby and Bachmann

All my track, locos and equipment has been bought from either Hornby shop or Rail of Sheffield, who I must say have had great customer service so far.

 

Thank You.

 

[WilliamDavid]

I suggest you check that any of the pins on the decoder socket are nor touching anything they shouldn’t. 

[Fishmanoz]

To me, sounds like 2 dud decoders. Contact your supplier again. 

[ColinB]

It might be the loco damaging them. It might be you have gained a short circuit from motor connection to track connection, the loco would work perfectly on DC but would blow DCC decoders. You need to check the DCC socket with a multimeter. Take out what is in the 8 pin socket and measure resistance between adjacent pins. You should get "open circuit" except between pins 1 and 8 which should be motor resistance (anything up to 100 ohms). Sometimes when people solder you get a hairline piece of solder between circuit board tracks, which causes a "short". The other thing is check that your speaker wires are not touching the weight in the tender, that would definitely damage the decoder. I initially had a lot of issues with TTS decoders, but I must confess, I am pretty sure it was me. I eventually bought a tester (about £30.00) so I could check units before I fitted them.

[Rilo]

Morning all, thank you for all the suggestions and ideas.

To reply to you all I've listed my replys in order instead of three separate posts:

Firstly, all the pins are fine and nothing seems out of the normal so I can safely rule that one out,

Secondly, two did decoders seems the most likely to me as ive placed multiple 8 pin decoders in the loco and all work well.

Thirdly,  order myself a tester to be on the safe side, but would the short not blow the 8 pins ? 

 

Finally, I did a test on the loco pick ups, using a 9v battery and found that only 2 of the 6 sets of pickups were working.... (the very front set of wheels and one set on the tender) this hasn't been a problem for the 8 pin decoders and because of the spacing  between the active pickups, I assume this is why it didn't stall over points. Never thought to check this out mainly because the loco is about 4 weeks old and was brand new out the box...

Anyway, I tweeked the pickups and now all pick ups are working, would this have caused the sound decoders not to work ?

But then this doesn't answer why they didn't work in another loco, which all pickups are active.

 

Once again thank you for all your help

[96RAF]

Some decoders can have slightly longer pins and hence may seat deeper into the socket and possibly touch a metal part on the loco/tender, which may be why the TTS decoder failed but the other decoder is OK. A safe thing to do is lift the socket and place a piece of insulating tape to cover the metal parts.

Colin’s meter check pin to pin on the socket should pick up any poor soldering, which is a fairly common fault.

 

As Fishy says it is likely you have been unlucky and gotten two bad decoders.

 

[ColinB]

There is an error in my first post should read pins 1 and 5, not 1 and 8.  I had tons of issues with my Britannia pickups and valve gear. I would readjust the pickups and it would work for a while. I did buy it second hand, perhaps that is why the person sold it. I have special edition black Britannia that is a bit older and that is perfect. The TTS do seem to be a bit susceptable to a bad DCC signal, I have had some locos stop and reset (you can tell by the startup of chuffing) whereas locos with just a DCC decoder are perfectly ok. I wonder if it is the extra current needed for sound.