Decoder issues

[Potrail2378]

Hi, I have a sound decoder - it has an 8 painted on it. The sounds work OK, the loco works OK, the directional lights in 'reverse' work OK. The problem is that the white wire (headlights) is permanently live, whatever the direction. It sounds like a simple short circuit, but nothing is obvious. Could it be something in the circuitry that is beyond my capability?

I once heard that doing a factory reset could make you lose the sounds, is that true?

Thanks in advance.

[Chrissaf]

I once heard that doing a factory reset could make you lose the sounds, is that true?

 

 

No ... not true.

The false rumour you have heard relates to Loksound sound decoders that support editable sounds. Technically, if the person loading the soundscape into a Loksound forgets to lock the decoder then the sounds can be lost in a reset. But a Loksound 'sound retailer' forgetting to lock the decoder after loading the sounds into it, is virtually an unheard of extremely rare event.

[96RAF]

The painted 8 tells me it is probably a TTS decoder.

A reset will not harm it.

Value 5 resets the sound only and value 8 resets the whole decoder to factory defaults including the address back to 3.

Tell us more about the lighting problem and we can probably sort that out as well.

[Potrail2378]

Hi 96RAF, the decoder works fine apart from the white wire being permanently live. I can only assume it's a short circuit but nothing is obvious. I'm hoping it's nothing too serious.

[Chrissaf]

When you say the white wire is live. Can you specify what voltage polarity it is, is it live negative or live positive. FYI the white wire when working correctly is normally 'switched negative'. If your obtained voltage reading is measuring the white wire voltage relative to the blue wire, then the white wire must be permanently negative.

In that scenario, then the semi-conductor component that controls the negative output on the white wire may have failed and gone 'short circuit' to the negative voltage rail within the decoder circuitry.

[Potrail2378]

Yes. I meant to say permanently negative polarity in relation to the blue live wire.

Would a factory reset help?

[Chrissaf]

No harm in trying, but if that doesn't resolve it, then I suspect my short circuit semi-conductor diagnosis is the correct assessment, which would mean there is nothing you could do yourself to fix it.

[ColinB]

I had exactly this same fault with the white wire being permanently live. In my case I had accidentally shorted it to the blue wire in the wiring, so the output driver had gone permanently short circuit, making it live all the time. Sadly to fix it, it is a return to Hornby.

[96RAF]

I agree with the above answers. It would appear the white wire function (F0 fwd) is permanently switched on, regardless of F-key or direction. I.e. decoder is kaput in that respect.

Whilst the TTS decoder motor output is self protecting against short or overload the function outputs are not protected so liable to failure if abused.

If less than 1-year since purchase ask Hornby about a replacement under their no-quibble warranty which includes user induced damage (i.e. ham-fistedness, etc).