DC/DCC Switching on locomotives?

[hartleymartin]

Does anyone know of a successful way to wire in some sort of switch that would isolate the DCC circuitry and switch the motor directly to the pick-ups? A lot of my friends now have DCC on their layouts, but I only operate on plain old-fashioned 12-volts DC at home (Well, PWM 16 volts if you want to be technical).

 

Is there a way to wire some sort of by-pass switch? I know that DCC chips are supposed to have some sort of function where it recognises DC voltage and operates accordingly, but every chip that I have ever had has been burnt out as a result.

[Kiwi]

Does anyone know of a successful way to wire in some sort of switch that would isolate the DCC circuitry and switch the motor directly to the pick-ups? A lot of my friends now have DCC on their layouts, but I only operate on plain old-fashioned 12-volts DC at home (Well, PWM 16 volts if you want to be technical).

 

Is there a way to wire some sort of by-pass switch? I know that DCC chips are supposed to have some sort of function where it recognises DC voltage and operates accordingly, but every chip that I have ever had has been burnt out as a result.

No need for wiring. The feature is built in to most DCC chips. Your friends just need to program their locos to allow DCC running.

[hartleymartin]

My controller is a Pulse-Width Modification type unit built from a kit, which has fried a couple of decoders over the years. Mind you, it is possible that decoder technology has gotten better since then and this may no longer be a problem, but I would still prefer not to fry any more chips!

[John K]

Free advice.

Do not mix DC and DCC. However clever you think you are, it will end in a tiny puff of blue smoke, a slightly acrid small; and tears.

John

[hartleymartin]

Hence, why I am asking for a way to isolate the DCC chip and run power directly from pick-ups to the motor.

 

I did achieve this once by using small plugs, but this involved taking the body of the loco off, unplugging the leads for the chip and then plugging the leads in together directly from the pick-ups to the motor.

[Suzie]

Decoders should be able to withstand up to 27V if they are NMRA compliant, so it should be possible to keep the output of your DC controller below that. That the controller is PWM should not specifically cause damage, just check the voltage coming out of it.Decoder fitted locos will be much happier on smooth regulated DC, but if the PWM is fast enough they should behave.

 

There have been some cheaper decoders and some very expensive sound decoders that are not really fit for purpose being sold, and hopefully there are not too many of those around now. They would tend to let out smoke on DCC as well so failures might just be co-incidence. Fit good quality decoders with a good guarantee and don't bother with a switch. In practice a 4-pole switch will be far too bulky to be practical.

[Crosland]

PWM can confuse decoders, but should not damage them.

[Nigelcliffe]

If its a PWM controller, with a known history of wrecking decoders, then I'd find a way around the problem.

 

At the loco end, its either wiring in the loco, to allow the switching of four wires, or removing decoders from sockets and fitting blanking plates.

 

Or, at the control end, replace the PWM controller with something delivering pure (or at least less noisy) DC.

 

 

 

I've known well regarded PWM controllers, such as the Pentroller, confuse some very well regarded DCC decoders.  

 

 

- Nigel

[34theletterbetweenB&D]

Hence, why I am asking for a way to isolate the DCC chip and run power directly from pick-ups to the motor.

 

I did achieve this once by using small plugs, ...

I think there are two simple options on the locos.

 

On locos where the installed decoder socket can be made readily accessible - such as under a lift out/off panel or bodywork piece (there are a few such among RTR OO locos where little or no modification is required) - then swapping plugs between decoder and the 'blanking plug' for DC operation suggests itself. (Added convenience if there is more than just the loco motor to control, all functions are thereby switched.)

 

Otherwise use of miniature four way plugs and sockets to connect track power and motor leads either via a decoder or directly will do the job for motor control alone (Plug into one or the other of two sockets or vice-versa.)  Unless of course a four pole double throw subminiature switch both small and cheap enough can be found,  which is the direct equivalent in action.

 

 

My controller is a Pulse-Width Modification type unit built from a kit, which has fried a couple of decoders over the years...

 Alternatively, rather than circumvent the problem on every loco, it would be worth looking at the output from the controller. It may be that a relatively small circuit modification will eliminate the decoder destruction capability (and it may well be good for your DC locos too).