Inexpensive DC power for your layout or bench

John,

That sure does make it convenient!!  Yes, I do have a couple ATX supplies in my computer odds and ends boxes.  Thank you for the tip!!

Thanks for sharing, John. Here is a very cool, 12 volt DC, Distribution Board that can be used with it to spread the 12 volt side over a layout. What is cool about it, it takes spade type fuses that if one blows an LED will light up under the blown fuse.  Item: #G22395, $10.00 Electronic Goldmine.   http://www.goldmine-elec-produ...fo.asp?number=G22395

Great idea John. I already have two old wall warts (and counting) under the table for DC. This would clean it up nicely. Now to hit up my IT guys at work for a power supply.

Bob

Great Great Great ..... Thank You .. for this and all your contributions to the Form.

Attached is my current version I ridged for some LED strip lights .... don't laugh ... 

Ordered one

Thanks again,

Rick

Dave Zucal posted:

Thanks for sharing, John. Here is a very cool, 12 volt DC, Distribution Board that can be used with it to spread the 12 volt side over a layout. What is cool about it, it takes spade type fuses that if one blows an LED will light up under the blown fuse.  Item: #G22395, $10.00 Electronic Goldmine.   http://www.goldmine-elec-produ...fo.asp?number=G22395

Price went up a bit!

John, here's one for $8.00.   http://www.goldmine-elec-produ...o.asp?number=G22395A 

Yep, damaged posts, and there's a $10 minimum there.  Interesting, but I'm not sure I need that current capability.

Hey John,
I noticed you were using a Dell power supply. He is a caveat on those
supplys that I came across a long time ago. It only pertains to the early ones.
My guess is, that the board is designed for a stantard ATX connector, so some
of the old Dell pwrsplys might not work with out some mods.
Joe

Yep, I do realize that, but I knew this one was the standard ATX pinout as I was using it with a standard ATX MB when it was in use.  I never got bit by that one, but I did hear about it.

gunrunnerjohn posted:

Yep, I do realize that, but I knew this one was the standard ATX pinout as I was using it with a standard ATX MB when it was in use.  I never got bit by that one, but I did hear about it.

I got three of those power supplys. I just "wacked" the connectors off and hardwired

them to terminal blocks. Not as  "clean" but hey, it works.

Thanks for the info.

Joe

Thanks John. I have several power supplies laying around that I've thought of converting. That's cheap and easy. I'll pickup a couple.

gunrunnerjohn posted:

Dave Zucal posted:

Thanks for sharing, John. Here is a very cool, 12 volt DC, Distribution Board that can be used with it to spread the 12 volt side over a layout. What is cool about it, it takes spade type fuses that if one blows an LED will light up under the blown fuse.  Item: #G22395, $10.00 Electronic Goldmine.   http://www.goldmine-elec-produ...fo.asp?number=G22395

Price went up a bit!

Sellers often put an absurd price on items when their out and expecting more in. Keeps them from having to kill their ads and reposting when new stock arrives

I figured that was the reason, but it was amusing when I went to check it out.

What a great idea. Thanks for posting John. I just ordered one.

Dave Zucal posted:

John, here's one for $8.00.   http://www.goldmine-elec-produ...o.asp?number=G22395A 

I looked at this link today and they show SOLD OUT.  Do you know of another source?

Thanks

Thanks john I just ordered 2 of them I have a lot of old computers it will be nice to get some use out of the parts.

DS Texas posted:

I looked at this link today and they show SOLD OUT.  Do you know of another source?

 Dave, here's another, and there are several other sources.

24/20-pin ATX Computer PC Power Supply Bench Top Power Board Module Adapter GW

John, is the spacing of the output jacks the same as a TIU?  I like using the dual banana plugs.

Not sure, I'm not at home right now, so I can't check.

There appears to be a variant with different jack spacing.  The jacks on the bottom board in photo appear evenly spaced left to right.

I just wired a rectifier to my AC transformer so I would have DC when needed...

Marty

Martin Derouin posted:

I just wired a rectifier to my AC transformer so I would have DC when needed...

Marty

SAME

SANTIAGOP23 posted:

Martin Derouin posted:

I just wired a rectifier to my AC transformer so I would have DC when needed...

Marty

SAME

You guys are missing the point.

What GunrunnerJohn has suggested is a separate and independent source of very cheap DC power. Putting a rectifier on your AC transformer will certainly provide some DC power, but you are drawing it from the same AC transformer that may be close to maxed out just powering the trains you run. This method avoids that problem and provides a source of very clean, smooth and heavily filtered DC power for the other needs you may have on your railroad.

Thanks Rich, you saved me the trouble of explaining it.   Many (most?) people probably have a dead PC around with a working power supply that will supply at least several hundred watts of pure DC power, so the cost is just a few bucks for the handy binding posts, fuses, and connections to the supply.  Putting a rectifier on your transformer will either yield half-wave DC for a diode or full-wave DC that does NOT have a common ground with the AC.  Lots of times, you would want filtered DC power, more expense.  Finally, this supply puts out a known voltage, having a rectifier and maybe a capacitor for filtering puts out a variable voltage based on load.

On the question of spacing for dual banana plugs, the terminals are NOT correctly spaced to use those, bummer.

Thanks John for checking that spacing.

Yep, bummer that it wasn't 2mm, that would have been nice.

Yes John and Rich, I got it right away.  Mine is on order, and my ATX power supply is sitting on the bench waiting.

 Thank you!!

On your supply, the thing to check is if the voltages match the standard ATX supply mapping.  Some Dell power supplies had a different pinout, but many did match standard ATX supply mapping.  Since you have 20 pins, check the mapping to the left hand example.

This one appears to have the altered spacing Stan mentioned, it may be compatible with the dual banana plugs.  Maybe people asked for it?

24/20-pin ATX Computer PC Power Supply Bench Top Power Board Module Adapter GW

Yep, black is common DC ground for all the voltages.  The -12V and -5V are negative in respect to DC ground, they're typically low power outputs.  On many supplies, there is no -5V, that's an optional output.  For instance, my supply has no -5V, the -12V is a 1A maximum current output as well.  The +5SB is the standby power, it's available even when the supply is off unless the main power is also off.  That powered the startup circuits on the motherboards for the soft power-up.

gunrunnerjohn posted:

Yep, black is common DC ground for all the voltages.  The -12V and -5V are negative in respect to DC ground, they're typically low power outputs.  On many supplies, there is no -5V, that's an optional output.  For instance, my supply has no -5V, the -12V is a 1A maximum current output as well.  The +5SB is the standby power, it's available even when the supply is off unless the main power is also off.  That powered the startup circuits on the motherboards for the soft power-up.

 Gotcha. Probably should take those speakers out too. Who knows what might come up where I'll use/need em

As nothing mapped out, Shoulda checked my pin count.  Only 18 pins. Search revealed my power supply but no map that I could find

Per the thread title, another low-cost source of DC power is a 12V DC "brick" which you may have lying around from a consumer gadget...or buy one for less than 10 cents per Watt.  For example, from a previous OGR thread:

Many bricks and wall-warts use the coaxial-barrel style connector.  In above, seller supplies a "free" adapter to screw terminals though you can buy them for 50 cents or so on eBay.

If fooling around on the bench before committing an accessory/lighting to the layout room it's handy to measure the current.  Yes, you can use a DMM but for $3 (free shipping) you can wire up a DC combo volt-current meter - no soldering.  These meters have been discussed many times on OGR.

The key is it's simply two-wires in, two-wires out.  Self-powered, compact, and for $3 (free shipping from Asia) I think a nice add-on even for the ATX breakout board.  Since they operate from 4.5V to 30V DC it could be used for the 5V output or the 12V output.

gunrunnerjohn posted:

This one appears to have the altered spacing Stan mentioned, it may be compatible with the dual banana plugs.  Maybe people asked for it?

24/20-pin ATX Computer PC Power Supply Bench Top Power Board Module Adapter GW

Those look like 20mm (length) fuses...and the connector spacing within a pair look a tad under the fuse length so it probably is the dual-banana "standard" spacing of 0.75" (19.05mm).

Just order one plus a spare. I will post what the spacing is when they get here. I'm keeping my fingers crossed.

I think you might be happy.  It appears that you weren't the only one that wanted dual banana plugs to fit, I suspect that's why the next generation has that spacing.

John

This is a ATX-250PA (1)    from a e machine not a dell.

It looks right BUT,   I would like to ask if it's ok to cut all the other

wires off and just leave  the 21 pin connector?

Thanks

Larry

Well, it's a 24 pin connector, not a 21 pin.

That's fine to remove the other wires.  I actually opened it up and clipped them totally inside and made sure they couldn't short to anything as well.

Thanks John

I have no idea why I said 21??? right after I counted 24 .......a dumb moment.

I really can count

Larry

That adapter looks and sounds great! You couldn't buy the parts and build it yourself for that, less than $7 and free shipping! So what if it's economy shipping, I'm in no hurry for it right away. I'm going to order two of them. I have one good used PC power supply Delta DPS-225HB A   for one and I know my brother-in-law has got to have one kicking around his stash of computer parts, then I can have one for the layout and one for the testing station. both in development modes so far. Thanks John!