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RE: How to convert an ATX power supply to rc use
ORIGINAL: OldRookie Try this one. A little higher price, but you are guaranteed that it is manufactured, and carries the Meanwell brand name. This is the one I use, and I use my computer power supply that I built as a back up. Some of the converted computer power supplies will make some chargers get a false peak, and terminates the charge prematurely. If you get one of these, make sure you select 120V, on the AC input voltage switch. I also replaced the cheap two wire cord that is supplied, with a 3 wire cord. http://cgi.ebay.com/12V-DC-29A-350W-...item19c31eb598 Greg This is the one I purchased. http://cgi.ebay.com/ws/eBayISAPI.dll...m=390096861039 <br type="_moz" /> |
RE: How to convert an ATX power supply to rc use
dmartin2010, I think the one yo got is just fine. First of all it's being shipped from the USA and not china (shorter shipping time). Second you can talk to the seller easier.
Some of the other thinks that Oldrookie mentioned would be worth the modifications. Good luck.. Larry |
RE: How to convert an ATX power supply to rc use
ORIGINAL: lbarnes dmartin2010, I think the one yo got is just fine. First of all it's being shipped from the USA and not china (shorter shipping time). Second you can talk to the seller easier. Some of the other thinks that Oldrookie mentioned would be worth the modifications. Good luck.. Larry <br type="_moz" /> |
RE: How to convert an ATX power supply to rc use
Guys I need your assistance. Going by information posted here, I used a 200W ATX to built a power supply unit to power my Accucell 6 charger, and it works great. I have +5 V, +12 V and a common terminal and an on/off switch, but would now like to install a power on led light, but am not sure how to connect it. Would appreciate someone telling me how. Thanks.
Karol |
RE: How to convert an ATX power supply to rc use
Well, go to radio shack and get a LED indicator (lot's of choices) and the dropping resistor for 12V.
Wire the dropping resistor in series with the LED and then connect the Neg side of the LED to the Neg side of your 12V output nd the positive side to the + side. Radio Shack has a lot of options for indicator lights and you should find one fairly cheap. Larry |
RE: How to convert an ATX power supply to rc use
Larry,
Thanks for your response, but could you explain what the 'dropping resistor' is for. Karol |
RE: How to convert an ATX power supply to rc use
Well, LED lights just by themself operate on 2 -3VDC. This depends on the size, color and type of LED.
When you go to radio shack the package will tell you the forward working voltage of that LED. Depending on what the source voltage is (5 or 12V) you will need a dropping resistor to reduce the source voltage to the working voltage of the LED. I have also seen some power indicators that are housed in a nice looking LED holder and then already have the resistor install in the holder so you just hook up to 12Vdc and your good to go. Larry |
RE: How to convert an ATX power supply to rc use
Thanks.
Karol |
RE: How to convert an ATX power supply to rc use
You can pick up an LED from most any electronics shop or on-line. LEDs are polarized which means that the leads must be connected to the correct positive and negative rails. If it is a new LED, the positive (or anode) connection will be longer. If used, the negative side (or cathode) will be the lead closest to the flat on the side of the base. Place a 180 ohm 1/4W dropping resistor between one of the leads and the powersupply rail - the resistor is necessary to control the amount of current passing thru the LED. Connect the positive side to the +5 rail (red) and the negative side to a ground rail.
The easiest way to mount the LED is to use a 1/8" grommet. Drill the case just large enough to snap the grommet in place and push the LED into the hole - a diffused lens LED will show up better from the side than one with a clear lens. andrew |
RE: How to convert an ATX power supply to rc use
Which of the led leads is a better option to place the resistor, the negative or positive.
Karol |
RE: How to convert an ATX power supply to rc use
ORIGINAL: karolh Which of the led leads is a better option to place the resistor, the negative or positive. |
RE: How to convert an ATX power supply to rc use
Thanks.
Karol |
RE: How to convert an ATX power supply to rc use
Karol,
I didnt reliaze your in Jamaica.. You most likely dont have a Radio Shack down the street. Follow Andrew's instructions and you will be ok. Larry |
RE: How to convert an ATX power supply to rc use
Will do, no problem.
Karol |
RE: How to convert an ATX power supply to rc use
Please take a quick look at this, if you get chance:-
- http://www.rcuniverse.com/forum/m_10433998/tm.htm - I have now blown two ATX psus!!! - Many Tks, Steve |
RE: How to convert an ATX power supply to rc use
I also need some help...electrical for dummies.
I purchased a coolmax CA-400 and when I plug the PS into my old desktop, it works. Without the any connections I get no output voltage. The Users manual for the PS says the following "A short circuit on any DC output will cause the power to latch. The power supply will withstand a continuous short circuit to the output without damage or overseers to the unit. The +5VSB can be shorted indefinitely and will recover automatically when the short is removed." I bought the 10W/10O resistor and I am pretty sure I need to solder the resistor to the +5VSB noted in the instructions above to get output voltage. Two questions: 1. Is this correct and 2. Which wires are the +5VSB? Step 5 in the original thread said to look on the big plug for a connection with 2 wires going into it...I will have to look when I get home from work, but does this sound right? Also, the specs on the PS are: 3.3V@30A, +5V@28A, +12V1@14A, +12V2@15A, -12V@1A, [email protected] My thought was keep the 2 12V output separate so I could run 2 chargers from the single PS which woulud give me 168W and 180W. Any thoughts? Thank you in advance!! |
RE: How to convert an ATX power supply to rc use
ORIGINAL: StevieM Please take a quick look at this, if you get chance:- - http://www.rcuniverse.com/forum/m_10433998/tm.htm - I have now blown two ATX psus!!! - Many Tks, Steve andrew |
RE: How to convert an ATX power supply to rc use
ORIGINAL: bpenner697 <snip> I bought the 10W/10O resistor and I am pretty sure I need to solder the resistor to the +5VSB noted in the instructions above to get output voltage. Two questions: 1. Is this correct and 2. Which wires are the +5VSB? Step 5 in the original thread said to look on the big plug for a connection with 2 wires going into it...I will have to look when I get home from work, but does this sound right? My thought was keep the 2 12V output separate so I could run 2 chargers from the single PS which woulud give me 168W and 180W. Any thoughts? Your load resistor should be attached between any +5v rail (red) and DC ground (black). Even with a load resistor in place, the PS_ON rail (green) will need to be shorted to ground (black) to get the PSU to latch on. 2. The 3.3v remote sense will be either a smaller gauge brown or orange wire attached to one of the 3.3v rails (orange). These two should be tied together when you make the conversion. The remote sense wire is used by the regulation circuitry to maintain 3.3v at the point where the connector plugs into the MoBo. It was added to compensate for voltage drop on the 3.3v rail due to long cables used to fullsize towers and when the board pulls more power. CoolMax does have a good reputation in the PSU market, but even though the specification placard states a max of 348W for 12V1 and 12V2 combined, it is likely overrated and you may not pull that level of power continuously. Some supplies have separate circuits for 12V1 and 12V2 and some simply pull both rails off the same pad. You can still run dual jacks for two chargers, but just keep in mind that full power simultaneously from both rails may not be feasible. andrew |
RE: How to convert an ATX power supply to rc use
Andrew...thank you much for the reply. I will trying the mod hopefully this weekend.
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RE: How to convert an ATX power supply to rc use
one other question...i have a 4 pin connector that has 2 yellow and 2 black. Is it safe to assume this is the ATX12V2 line...it's not a yellow striped wire? All of the wires are yellow and none are striped.
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RE: How to convert an ATX power supply to rc use
Its been raining sideways for a week, there is no end in sight, the outlaws will be here all weekend for Easter, my wife is wired (no pun intended) so I figured; why not convert that Compaq power supply? Shocking myself unconscious until Monday morning isn't looking like such a bad thing!
But it didn't work. Here is what Idid based on about as much reading (including this thread) that I could do: 1. Orange and browngrouped together. 2. Red grouped together. 3. Black grouped together. 4. One black to a 10-Ohm 10 watt resistor; one red to the other side 5. One black to a LED w/built in resistor (black wire side of LED); The onlygrey wire present; attached to other end of LED (red wire side of LED) 6. One black to DC switch and the only green wire present; attached to the other side of the switch 7.The following wires are leftover (kind oflike the extrabolts on that swingset from 25 years ago that is stillstanding in the backyard): One yellow (minus 5 volt) One blue (minus 12 volt) One purple (fan off and JP16) One white (the circuit board says 50 and JP24, can't tell which label is for the white wire) So Iplug it in and I don'tget anything. No LED, nofan, nothing. No smoke either http://www.rcuniverse.com/forum/js/f...sn/thumbup.gif I recognize that it might not be possible to get this debugged in this forum setting...that's ok.But if someone cansee a quick fixbased on what I identified that wouldbe great. If Icould just get it running Ican test all thevoltageswith my meter and make connections to my binding posts etc. Thanks.. |
RE: How to convert an ATX power supply to rc use
Great walk through.
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RE: How to convert an ATX power supply to rc use
Tom,
When I tried mine, I attached only the critical items first to ensure my PSU started. I did not and still do not have an LED or a switch. My PSU came with a switch on the back by the AC connection. I am NO expert but did get mine to work, mostly. I am still trying to figure out how to differentiate the 12V1 and 12V2 because the wires are all yellow. The only item I notice in your write-up is the connection of the green wire to the switch. When I asked the question, I was told (ref. post dated 4/1 by Andrew) that the green needed to be shorted to ground so I connected the green and black together and mine worked. My PSU shut off when I accidentally had it shorted out (thankfully) so I didn't smoke anything. Here's how much of an electrical idiot I am...I didn't use insulated binding posts and wondered for about a day while mine did not start. The light bulb finally went off and I figured that I had both the 12v and 5v lines shorted because of the posts I bought. I found the non-insulated posts at Radio Shack and then everything worked. I did re-install a new resistor this weekend and got the 12v line above 12v without a load (gained about 0.10v with 10ohm/10W resistor on the 5V line). When I connected my charger this weekend I noticed the output dropped to about 11.85 to 11.9v with load. I have 2 outstanding questions if anyone can help: 1. Is there anyway to increase my 12v voltage under load? Will a bigger resistor on the 5v line help? 2. How can I tell my 12V1 vs. 12V2 lines apart? I tied the 2 yellow wires (no stripes) off the 4pin connector and they have the same voltage with no load as the other yellow wires with load. I have 2 separate posts and 2 separate grounds with the hope of running 2 chargers from this PSU. Thanks again...Brian. |
RE: How to convert an ATX power supply to rc use
THANK YOU FOR TAKING THE TIME TO WRITE. PLEASE SEE CAPS BELOW:
ORIGINAL: bpenner697 Tom, When I tried mine, I attached only the critical items first to ensure my PSU started. I did not and still do not have an LED or a switch. My PSU came with a switch on the back by the AC connection. I am NO expert but did get mine to work, mostly. I am still trying to figure out how to differentiate the 12V1 and 12V2 because the wires are all yellow. WELL, I HAVE BEEN USING A MAGNIFYING GLASS AND A FLASHLIGHT TO TRACE A WIRE BACK TO THE CIRCUIT BOARD AND USUALLY THERE IS SOME KIND OF INDICATION PRINTED AS TO WHAT IT IS FOR. LIKE MY GREY LINE SAYS "AUX GROUND" AND I CAN FIND ALL THE -12V, +12V LINES ETC. THE SAME WAY. The only item I notice in your write-up is the connection of the green wire to the switch. When I asked the question, I was told (ref. post dated 4/1 by Andrew) that the green needed to be shorted to ground so I connected the green and black together and mine worked. YES, THE GREEN IS A SENSE WIRE AND BLACK (GROUND)IS THE OTHER SIDE OF THE SWITCH. I'LL ELIMINATE THE SWITCH FOR NOW THOUGH AND SEE IF I CAN GET SOMETHING TO WORK. I LIKE THAT IDEA. My PSU shut off when I accidentally had it shorted out (thankfully) so I didn't smoke anything. Here's how much of an electrical idiot I am...I didn't use insulated binding posts and wondered for about a day while mine did not start. The light bulb finally went off and I figured that I had both the 12v and 5v lines shorted because of the posts I bought. I found the non-insulated posts at Radio Shack and then everything worked. HEY...I CAN'T CALL ANYONE AN IDIOT ON ANYTHING...MY PROFESSIONAL PURSUITS ARE SO TOTALLY DIFFERENT FROM MY HOBBY THAT I CAN ONLY LEARN THIS STUFF BY READING AS MUCH AS I CAN WITH LIMITED TIME. SOME GUYS ON RCU TALK ABOUT THIS STUFF IN THERE SLEEP! I did re-install a new resistor this weekend and got the 12v line above 12v without a load (gained about 0.10v with 10ohm/10W resistor on the 5V line). When I connected my charger this weekend I noticed the output dropped to about 11.85 to 11.9v with load. YOU KNOW, I JUST CONVERTED A DELL POWER SUPPLY AND THE VOLTAGE DROPPED ABOUT THAT MUCH WHEN I CHARGED ONE OF MY A123 BATTERIES. SOMEONE SAID IT WAS MOST LIKELY BECAUSE I WAS PUSHING THE POWER SUPPLY, IT WAS PRODUCING ABOUT ALL THE AMPS THAT IT COULD AND THAT IS WHY THE VOLTAGE WAS DROPPING. I'M HOPING THE ATX UNIT WILL DO BETTER AS I WOULD LIKE TO CHARGE MORE THAN ONE BATTERY AT A TIME. I have 2 outstanding questions if anyone can help: 1. Is there anyway to increase my 12v voltage under load? Will a bigger resistor on the 5v line help? 2. How can I tell my 12V1 vs. 12V2 lines apart? I tied the 2 yellow wires (no stripes) off the 4pin connector and they have the same voltage with no load as the other yellow wires with load. I have 2 separate posts and 2 separate grounds with the hope of running 2 chargers from this PSU. TRY THE MAGNIFYING GLASS! Thanks again...Brian. |
RE: How to convert an ATX power supply to rc use
ORIGINAL: bpenner697 I have 2 outstanding questions if anyone can help: 1. Is there anyway to increase my 12v voltage under load? Will a bigger resistor on the 5v line help? 2. How can I tell my 12V1 vs. 12V2 lines apart? I tied the 2 yellow wires (no stripes) off the 4pin connector and they have the same voltage with no load as the other yellow wires with load. I have 2 separate posts and 2 separate grounds with the hope of running 2 chargers from this PSU. Sometimes (rarely), there is a small potentiometer on the board. If it's present, you can try tweaking it a little (no more than 1/8 turn at a time) and see what it does - if it does nothing, put it back where it was. Don't be surprised if you can only get around 13v or less because the overvoltage circuit may kick in. Another way is to mess with the brown feedback wire; basically make a voltage divider that fools the PS into thinking that the 3.3v line is outputting less voltage than it really is, so it boosts the output a little more to compensate. This in turns boosts the 5v and 12v lines too. There is a limit to how much extra voltage you will get before the overvoltage circuit kicks in, but that takes trial and error. Below is a pic that gives you an idea what I mean. Note that this pic is for a different type of mod, but the principle is the same. Where is says "12 Power" use an orange 3.3v wire, where is says "12v sense", use the brown sense wire. In this pic, the use of the two diodes makes the sense wire see ~1.4v less than what there really is. This makes the regulator boost the 12v output until the sense wire is at 12v, which makes the 12v line closer to 13.4v. If you were to do this on the 3.3v line, you should only use 1 diode and even that may be too much in which case you may be forced to use resistors only to have finer control over the ratio. http://scriptasylum.com/forumpics/ps3.jpg A final way to boost the output would be to modify the regulator circuit itself, but that's probably beyond but a very select few to accomplish. 2: You'd have to pull the circuit board out and see where the yellow wires attach. Usually, there is a bunch of wires that go to a single solder lug, somewhat like a bullet connector, that is soldered to the PCB. So, it's usually pretty easy to see what goes where. The grounds likely all go to one point electrically. <br type="_moz" /> |
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