Heljan Class 47 and TTS Sound Decoder

[Pierre Le Brun]

I've read on other posts that a TTS decoder wont work with a Heljan loco as it draws too much current and blows the chip. I wondered if its possible to wire a resistor in between the loco and decoder to reduce the current.  I'm not sure if this is feasible or if anyone has given it a go. 

[Pierre Le Brun]

5 minutes ago, Richard Croft said:

I think it could be the lights that cause the issue, as it uses bulbs rather than LED's, someone might confirm

 

Richard

Richard, If it's the lights I could remove them as it's not a deal breaker. Going off the topic I've recently installed the Railcar decoder I bought from you in my Dapol Express Parcels and the sound is excellent. As you know the only thing I changed was the speaker (personal preference only) and nothing to do with sound quality.

[Pierre Le Brun]

3 hours ago, Richard Croft said:

Thanks! Don't take my word on the TTS decoder just yet, let someone else confirm first! but I think I remember reading recently (on here) that the motor circuit on TTS is protected, so it would stop before it burnt out, but the lighting circuit isn't.

 

Richard

Thanks Richard, I'm not in a rush to do it. I've read in a previous post that cutting the blue wire will disable the lights or alternatively including a resistor on the blue wire. This was on a Bachmann Loco but may apply to a Heljan loco possibly. 

[RAF96]

I would replace the filament bulbs with leds and fit additional resistors to keep the current draw within limits of the decoder taking note that the more the lights use the less there is for the motor within the total decoder scope. The TTS motor circuit is self protecting but the functions are not - as previously stated by Richard.

i would do a motor stall current check with the decoder unplugged and a blanking plate fitted. This can only be done on DC, not DCC. That will tell you exactly how much current the motor will draw in the worst case scenario.

[Pierre Le Brun]

Having purchased  a TTS decoder this week for another loco and returned it as the sound didn't work I've decided not too go down this line. I would fit a Howes or similar sound decoder as I've never had a problem with them.