# DCC power supply



## JerryH (Nov 18, 2012)

Has anyone tried an ATX PC power supply with DCC? I am looking at a 300 watt PC supply that supplys 5 amps on one 12v rail and 13 amps on the other. This seems to adequate for Digitrax SCD 8amp plus 7 additional cards. ATXs are switched on by connecting the green and a black together on the 24 pin coonector. These are way cheaper and available locally than a PS2012. What do you think?


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## broox (Apr 13, 2012)

Not sure if it'd work, depends entirely on the input requirements of the Cab / Booster thingy. You can't get more power to the rails by simply giving more power to the Cab, thats completely dependant on its internal electronics.
But as a replacemet / substitute PSU... If the power and polarity and plug is right... ? maybe it might work?
I'd go for an name brand PSU over a cheapie, more stable power, especially if you're running at or near peak for any period of time.


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## waltr (Aug 15, 2011)

12V is a bit low for HO DCC but will work. Typical is more like 14-15V (read the Digitrax manuals).
You do want a power supply with a greater current rating (Amps) than the command station's current limit. This way the Command station does the shut-down in case of a short circuit instead of the power supply.
Another potential issue is isolation of the PS input(AC main) and the outputs. You want complete galvanic isolation. Measure between any output wire and all of the AC inputs with an Ohmmeter. They should measure Infinite Ohms or 'open'.
Lastly, do put an appropriate fuze inline with the power supply output.


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## JerryH (Nov 18, 2012)

I would put the SC8 on the 13 amp bus and the cards on the 5 amp bus. There is infinite ohms between the +12 vdc busses and black and both the neutral and hot AC terminals. There is 115 ohms +12vdc to the AC ground terminal and 2 ohms between 12vdc black and AC ground. I'm just trying to get rid of 5 power supplys and just use one.


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## broox (Apr 13, 2012)

The up side is theres plenty of 5v rails to run accrssories 
It wont look as neat as proper power supplies though, so much spaghetti... unless its a modular atx psu?

whats the required volts for the super chief? i read somewhere that it can take both ac and dc.


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## JerryH (Nov 18, 2012)

No spagetti. I will customize it if it works. SC specs and cards are 12 - 18 DC or AC. They seem to stress minimum amperage more.


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## JerryH (Nov 18, 2012)

I tested a PC pwr supply with a straight DC HO train today and at 12v it ran just fine similar to about a 57 setting on a MRC DC throttle. The back EMF readings were more stable with the PC supply. I will see what it does supplying a DCC booster.


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## broox (Apr 13, 2012)

keep us informed :thumbsup:


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## waltr (Aug 15, 2011)

broox said:


> keep us informed :thumbsup:


Yes, please do.


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## rrgrassi (May 3, 2012)

broox said:


> The up side is theres plenty of 5v rails to run accrssories
> It wont look as neat as proper power supplies though, so much spaghetti... unless its a modular atx psu?
> 
> whats the required volts for the super chief? i read somewhere that it can take both ac and dc.


My Super Chief gets AC power from an 8 amp power supply.


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## Southern (Nov 17, 2008)

Digiatrax list the DCS100 / DCS200 as able to run off of AC or DC.
The minum volt is 12. Max AC volt is 20 rms. and 28 volt DC. 
The current should be rated at 5 amps for the DCS100 and 8 amps for the DCS200

I power mine with the Digitrax PS2012.


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## JerryH (Nov 18, 2012)

ATX ps didn't work. It may have fried my DCS!!


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## broox (Apr 13, 2012)

Oh no! hope not :/

Are they fused intetnally to protect from things like this / power surge / etc..?


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## NIMT (Jan 6, 2011)

I'm sorry that I didn't catch this before you tried it. 
ATX power supplies DO NOT work for powering a Digitrax DCS command station. Some AT supplies will work, but still too risky to try and make it work! 
There is something about the regulator or power circuit in the ATX supply and the circuitry in the DCS that fight each other, way too complicated for me to even want to comprehend or explain it!
There is an overload safety on the output, but not the input on that unit so be careful what you feed it.
The DCS seems to like dirty power better than clean filtered power on the input.


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## JerryH (Nov 18, 2012)

No protection for anything. I worked with NIMT on it yesterday and he felt it was bad. I took it to the shop where I got from and they confirmed it was bad. They gave me a loaner to use while it is being warranteed. I now have trains running on DCC for the first time, and on my first layout ever, to boot. Ran them on all trackage and not a single short (amazing) but I haven't powered the frogs yet. Now I have to put in the Tortises, PM42s, BDL168s, SE8Cs, and a PR3. Hopefully I'll get that done tomorrow. Have fun running the trains today instead of working on the layout.


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## JerryH (Nov 18, 2012)

I bought a PS2012 today. That should be the end of it.


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## NIMT (Jan 6, 2011)

Glad to hear you got it running!:thumbsup:
I applaud your LHS for loaning you a working unit to hold you over!:appl:
Nothing worse than buying something and it not working like it should!
I bought one of the first DCS 200 when they came out and 2 weeks later POOF out went the smoke. 
No one had one of those hanging around so I had to wait a painful 3 weeks for a new one to show up, they didn't even fix mine it was way too fried!
I have never toasted another one sence so I would say it was a fluke!


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## Southern (Nov 17, 2008)

NIMT said:


> ..............and 2 weeks later POOF out went the smoke.


 
That is what happens when you run a billion LED off of it.


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## JerryH (Nov 18, 2012)

They didn't have a DCS200 but lent me a DCS100 which is fine for now. It seems Digitrax is closed till after the first.


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## NIMT (Jan 6, 2011)

Nothing!


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