Where did they fit the speaker on a railroad Mallard

[ColinB]

On the railroad TTS Mallard, is the DCC decoder still in the loco? If so where did they fit the speaker and what sort is it ?

[96RAF]

The Hornby TTS factory fit standard for tender steamers is in the tender for both the decoder and the speaker which is the standard 28mm round one. Pull any associated service sheet for a TTS equipped tender loco and you will see they are all very similar, usually only the weight shape varies.

 

e.g SS350 is the XS 21-pin sound A4 which will be very similar to the Railroad TTS version except for an 8-pin socket in lieu.

[ColinB]

Great, thank you. Mine must be an earlier railroad version without sound. I will use a sugar cube speaker in the loco.

[Leighton Cook]

Hi,

Was your Mallard a R2784X with a Dummy Ringfield Drive fitted in the tender as per Hornby Srvice Sheet HSS No. 344?

Did you modify a Hornby TTS decoder and fit a sugar cube speaker in the loco and not in the tender?

I just posted a comment/problem about the Mallard R2784X fitting a TTS decoder and speaker which you may be able to help me with.

Cheers,

[ColinB]

Sorry didn't see this post. Yes, you should see my answer. Yes, I fitted a sugar cube speaker in the loco itself, it is neater and there is room right at the front. I find that these things are so fragile, that it is a good idea to keep wire runs to the speaker as short as possible. I buy the speakers with the plastic top/bottom as you stick this to the loco without fear of the speaker connections touching the chassis. The speaker connections are on the top, so you can just stick a bit of insulation tape over them, in case the speaker ever falls off and tries to short out on anything metal. Yes I am pretty sure mine is the same loco, with the remanents of the ringfield motor in the tender. I also added lights, and a a firebox glow, so it sounds the same as your setup. It is annoying having to buy another speaker, but I am told the sound quality is better and they look a lot more robust. 

[Leighton Cook]

Thanks for your quick reply. i will do as you have done with the sugar cube speaker.

It`s just strange why the two TTS decoders fried when I fitted the speaker into the tender as it was fully insulated against the Dummy Ringfield Drive Unit.

I will seek answers from my electronic electrician friends so solve this riddle.

[ColinB]

Well believe or not I am an Electronics Engineer and I cannot explain why some of my DCC modules fry. Sometimes it is because a soldered connection on the board touches something, sometimes it is because a trailing wire touches something, but a lot of the time I cannot explain it. Some of the really cheap ones off EBay don't seem to have short circuit protection on the motor, because I blew a couple up when the motor was a a bit sticky. The only TTS decoder I blew was when the speaker accidentally touched the track, it was resting on the tender while I tested it before putting the tender back together. As the loco moved it fell onto the track. I do wonder about the extra metal though, another one failed after about a week and the only thing I had done wrong was put the speaker on top of the weight in the tender, the speaker was fully insulated. I suppose it could have got hot, but I would have thought that there was enough air flow in the tender to keep it cool. I have now adopted the KISS principle, and have the speaker and module as close together as possible, and insulte everything. Trouble is it only takes milliseconds to blow something up and sometimes the moduleworks for about a minute and then dies. From a previous post it says they use FETs as an output driver, and I do remember FETs were very easy to blow up with static electricity.

[Leighton Cook]

Hi Colinb

Thanks for your comments.

Can you advise the make and size of the sugar cube speaker that you fitted to your Mallard

Cheers.

[ColinB]

It was definitely a YouChoos sugar cube speaker, but as the size I am not sure, I think it was a Brick8 type. They were doing these at a discount, and they have normal soldered connections, some of the others have a spring solder connection which I don't like as when you start to solder it pings out. I like these as they have a plastic enclosure which you can stick to the loco, with the soldered connections pointing upwards, which makes it easy to cover with insulation tape. I have lost a couple of modules where I have been testing it with the body off and the speaker falls off and touches the rails, bye bye module. So now I am super careful.

[Leighton Cook]

Thanks Colin.