A friend has a number of N scale Spectrum Dash 8 chassis that they want to apply to a similar number of Australian Loco bodies. She is concerned about the start up voltage of the motors, the apparent lack of torque and the jack rabbit starts… I thought Spectrum was supposed to be an upper level Bachmann. I know relatively little about N scale trains characteristics so is this common? She is quoting a starting voltage of around 7 to 8 volts…
Many newer Dual-Mode DCC decoder-equipped locomotives have a high start-up voltage when running on DC.
This can be especially true with units that have sound.
In reading locomotive reviews in Model Railroader Magazine, when they are tested in DC the relatively high starting voltage is listed compared to the starting voltage in DCC.
This may have nothing to do with the motor but with how the motor receives its power.
If she is only running DC then removing the DCC decoder and converting it to DC only might be the best course of action.
By doing this she would lose any sound capabilities.
Its a trade-off- -sound functions vs. start-up voltage.
Thanks JJ… AFAIK she is only running variations of DC - I don’t think her chassis have chips as such but it is a bit hard to say as we live about 1200 miles apart - she is in Brisbane and I’m south of Melbourne - we’ve never met but the magazine has formed the working partnership. I am wondering if directional diodes for lighting might have a bit to do with it as well?
The green ‘lightboards’ many engines come with usually have a variation of constant lighting built in. The first couple of volts goes to the lights, then any power above that amount is what goes to the engine. The idea is/was that you could stop an engine from moving by lowering the throttle, but if you left a little power on, the lights would stay on.
My experience, back when I was in DC, was that removing the lightboard significantly reduced the power needed to start the engine moving. However, later when I converted to DCC, I realized many of the lightboards I removed had a DCC receptacle that would have made converting them to DCC much easier had I left them in!
As mentioned, if the engine is DCC/sound equipped, it can take a great deal of power on DC to get the sound started and the engine moving - more like the 7 or 8 volts you describe. If that’s the case, they may need to decide whether to buy a starter DCC system so they can run trains with sound more efficiently, or remove the sound decoders and sell them (or sell the engines and buy non-sound versions) and just run on DC.
Sounds like she is running a DCC loco on a DC track in DC compatibility mode. removing the decoder is the answer. Sadly it may be hardwired in and not socketed. Either way (socketed or hardwired) it will require wire tracing and soldering to the pickups, diodes, and resistors (for lamps)
Bachmann makes a practice of separating DCC locomotives from DC ones by never having the same cab number on the train. So a train #352 will be available in DCC, but not DC. And train #351 will be available in DC but not DCC.
John Glabb who worked tightly with Bachmann told me this. That way buyers could tell if a particular engine was DCC or not without putting it on the test track. The catalog will tell you based on the train #.
My HO Spectrum Consolidations misbehave in DC mode with older Digitrax motor only decoders. Took out the decoders and fitted a jumper plug. They run fine in DCC mode with the decoder installed.
Modern sound decoders run fine in DC but have a much reduced voltage range because the sound effects require a high minimum voltage so motor start voltage seems high. Motor only decoders do not have this problem unless for some reason they have been speed matched to a sound decoder equipped locomotive (the B unit for exam in an AB where only the A has sound).
DCC with sound won’t run well together with non sound or DC only locomotives when in DC mode.