New to DCC (Powering my HM7K factory fit loco).

[Kettering Junction]

I received my King Charles 66 today and being new to all this, I assumed it would work on DC. Not the case. I downloaded the HM app and fiddled about (not really knowing what I’m doing!) just to see if it would work and to my amazement I had power and sounds! All I have is the app and the basic gaugemaster controller, no fancy digital controllers or adapters. Should this actually work with my setup or will I cause damage to the loco?

Thanks!

Mod note - title amended to describe your post

[LTSR_NSE]

It is not advisable to use the HM | DCC (HM7000) app with a DC controller or power supply unless it is one of the approved ones in the following list:

HM7000-TXS_TRI-MODE_-_Compatible_Controllers_and_Power_Supplies.pdf

Using an unapproved/inadvisable controller can easily damage the decoder in your loco.

For more information about HM7000 decoders please see:

https://uk.hornby.com/hm7000/hm-dcc-guides

[LTSR_NSE]

Further to @Daedalus’ post - You do also need to ensure that your power supply (or controller) includes voltage smoothing, short circuit protection & overload protection - which all of the approved ones in the list I posted do!

[96RAF]

Do not use the speed knob controlled output from the Gaugemaster controller. This has been proven by you-tube influencers who did not read the instructions and warnings to damage decoders.

As stated use a wall mounted PSU output direct and put the controller away for now.

[ColinB]

Has anyone actually worked out why the Gaugemaster controllers damage this device, or did I miss that post. Generally is it too high a voltage or heat dissipation issues. I know from practical experience that old Hammond and Morgan controls damage DCC decoders, but then my old one was designed for a Wrenn or Triang locos. Zimo also have a note on one of their smaller decoders not to use it with DC, again I can figure the reason. The Gaugemaster being a relatively new controller should be ok. Perhaps if we knew the reason we could suggest a suitable fix.

[Brew Man]

I believe it is the PWM aspect of many DC controllers that can cause damage due to the potential spikes on the supply that they produce. Documented many times here.

[SteveM6]

Perhaps if we knew the reason we could suggest a suitable fix.

 

 

We know that it is the uncontrolled spikes that cause the problem and we already have the fix - only use an approved power supply from the list that Hornby have already published

[ColinB]

Yes, I remember reading that post, so just a capacitor across the output should fix that, but thinking about it, it has got to be more than that.

[96RAF]

To clarify this even further - yet again.

The speed knob controlled output from these analogue controllers can be spiky. Now whilst those spikes may be within decoder limits for say moderate running in speeds with the decoder in DC mode, when the controller was turned to maximum as initially allowed (but now vetoed), the spikes seen were far outwith the decoder limits, some as high as 40 volts. The decoder limit is 27 volts but generally a smoothed 15-19 volts is recommended, as you should never work any electronic device at its extreme limits.

Initially the spikes were noted as causing sound distortion, but further lab investigation and service experience found they could actually damage the decoder.

[Kettering Junction]

Thanks all, it only did one lap so I’ll pack it away until I’m DCC ready! Hopefully it’s ok 🙏🏻

If I put a blanking plate in it, would that convert it to DC? Excuse my lack of knowledge on this.

[Brew Man]

Yes, a blanking plate will revert it to DC operation.

[Fishmanoz]

But if you buy either a P9100 or P9300 PSU and adaptor cable, you can run with sound on the app. No need for a DCC controller.