mustang1964.5

yeah thanx for the repply i was wondering about that +12v and +5v=7v i didnt know wich to use as negative/ground. and yes i have ATX power suply i will buy some resistors tomorrow and give it a try, my biggest concern here was not to fry the heli 4-1 so i will try that and monitor the motor temperature wich i know mine with out motor sink is 130 F temperature after a discharging the 2c li-pos. thanx

mustang1964.5

hi andrew i just tried wat u told me "5v rail (red) as ground and the 12v rail (yellow) as positive" and the heli does not even turn on and when i use the black as ground cable and red cable (5v) as positive the heli turns on and the blades spin but does not have anough power to hover.

Andrew

Does your supply not have any resistive load across the 5v rail? Secondly, have you measured the voltage across the +5 and +12 rails to be sure you are getting power?

mustang1964.5

hey andrew, no resistance load across 5v cable, yes i measured the volatge across +5 and +12 and i get close to 7 volts if i put the ground cable from the volt meter to red +5 and the red from the volt meter to the yellow +12 i get close to 7 volts and if i do the oposite black volt meter cable to yellow +12 and red volt meter to red +5 i get - (negative) 6.something volts. and sorry i told u i was using and ATX but i think is the other type.

Andrew

The readings are to be expected, including the polarity reversal. The resistive load will probably increase your 12 volt output and the differential should be very close to 7 volts. Most of the 5v rails read in the neighborhood of 5.05 to 5.15 volts. You can sometimes push the 12v rail up to 12.2 or so.

However, I can't provide a reason why your heli won't run with the 7v input. You need to be mindful of motor heating -- without a battery to run down, don't try to run too long without a cooling off period. Secondly, silver satin phone line is pretty heavy with the outer insulation sheath -- you can drop some weight by peeling the outer insulation away and using just 2 of the inner wires. Lastly, the wire gauge in phone extension line is very light and may not carry the current needed by your motor, especially over a long distance.

mustang1964.5

thanx thats great advise. regarding wat u said "The resistive load will probably increase your 12 volt output and the differential should be very close to 7 volts." i get that resistive load in the red wire +5v will push the yellow wire +12v up thanx for clarifying, i was wondering, can i push the red cable +5v higher with the resistive load and if yes i'm guessing i put it across red and black same way to push up yellow cable?


about the heli not turning on by using red and yellow and turning on with black and red i dont know either. i measured volts coming out the supply cables and measured across the cable that i attached to the heli and got same reading. the only thing that i did different to the power supply was removed the fan but i have it on all day every day because i'm using it to power up a 12v hub. and i check the temperaure and is not even warm. but i will try with another power supply tomorrow ATX this time.

u gave me a good advise about the cable i'll take ur idea about using only 2 innner cables. luckly i have phone cable that goes in the walls i have about 200 feet and the sheath u can take it off by pulling a small string that runs inside the cable. the gaude is thicker then phone cable thats used to connect to wall rj-11 jack, thanx.

hands without shadows

Hey, Im am really sorry but I completely forgot about this thread!!! Back to my problem......Andrew, you asked if I get voltage on the +5vsb line and on the ps_on line, I assume between those and negative. I get 4.26 volts between negative and the +5sb, but not between ps_on and negative. I do get voltage between pwr_ok and negative.

hands without shadows

Anyone?

Dhenry

Hi I have converted an ATX switching PS. I checked voltage accross the binding posts and it shows 13 volts, but when I hook up my parkzone charger to it, the PS shuts down. Any help would be great. Thanks in advance. Don

Andrew

Hook your charger to the PSU first, then turn the PSU on.

Many chargers have ripple suppression caps on the front end and, when discharged, represent a sufficiently high current sink to trip the overload circuitry of the PSU. However, the ATX Design Guidelines state that the PSU should be able to power up and stabilize with a 4700 uf capacitive load on the 12v rail -- this is due to the high capacitive load on the current motherboards. Once the PSU has stabilized, high current sinks are then identified as a possible short, the overload circuit captures and the PSU shuts down.

This solves the majority of Power_Off situations when the charger is attached, but if not, you may have to look to another power source.

Enticer

I am trying to convert an older AT power supply. My question is what do I do with the brown and blue wires shown in the pic They were attached to a pigtail that connected to a switch on the front of the computer.

cwharper

I've just done two PSU to +12volt conversions. One was 180 watts ATX (Hewlet Packard) and the other 420 watts ATX (Raidmax). Following is a short description of what I did to each and the unique findings of each:

180 watts (Hewlet Packard) 15A on +12v rated

The wires on this one followed the instructions from here:

http://www.wikihow.com/Convert-a-Com...b-Power-Supply

The only exception was the brown wire which did not exist and did not find any other sense wires. I used the 10 watt 10 ohm resistor across the 5 volt rail and mounted it on the air vent grill with some thermal grease using regular twist ties through the grill. There were six yellow wires total and I soldered all six to a binding post and six black wires to another binding post. Everything else I didn't use I cut off so no wires were hanging out when I put the cover back on. Voltage read at 12. 27 volts with no load. I connected the Triton2, turned the psu back on and cranked up the charging amps to the highest setting. Triton2 said it was charging at about 20.5 v and 4.4 amps and my clamp meter said the Triton2 was drawing 9.4 amps from the psu. This confirms the 90 watt max of the Triton2. The source voltage read 11.04 v on the Triton2. However a quick check from the binding posts read 11.51 v under load. This psu appears to have plenty of power for the Triton2. I wonder why there is such a voltage drop from the banana plugs to what Triton2 two says it's getting? One other note, this psu did not power the Triton2 adequately under full load without the resistor.

Alright now the 420 watt (Raidmax) 13A on +12v rated

This one was a little more tricky and had me stumped for two days. Before I cut any connectors I tested the psu by jumpering the green to a black wire within the 20-pin connector and putting a 10 watt 10 ohm resistor across the 5 volt side of one of the molex connectors. The psu powered on and I had 12.18 v on the +12v rail. So it works. After I cut the connectors off and then regrouded the green wire and the resistor the psu would not power on. I got only the fan bump. Couldn't figure this one out until two days later I decided to count the wires which came from the 20pin connector. I thought well maybe there was a sense wire I missed but didn't find any brown wires. So I counted 21 wires in that bundle. Ha!! I went back the connector I had cut off and sure enough one pin had two wires in it. Both were orange but one was smaller gauge than the other. I connected these back together and the psu powered on. On this one I mounted the resistor on one of the aluminum heatsinks with thermal grease and twist ties. The rest of the conversion went according to the instructions. Voltage under full load from the Triton2 was 11.69 volts at the binding posts and Triton2 said it had 11.19 volts. So it appears this psu had slightly better voltage regulation.

What I learned from this:

- Soldering paste makes soldering a lot easier even when using rosin core solder
- After stripping the ends of the yellow or black wires and then twisting these ends together I learned that putting a dab of solder at the
base of the twist will hold the bundle together while you manuever them into position for soldering to the binding post.
- My "powerful" handheld spotlight only draws 3.8 amps from the psu at 11.8 volts.
- I tried the spotlight on the 5 volt side instead of the resistor and got nearly the same results as the resistor, except I was burning more watts with the spotlight than with the resistor.
- That sandbar resistor can become skin burning hot without a heat sink.

soyer

sorry i didnt want to start another tread so ill post it here but i converted a old atx power supply it powers and on but im only getting 11.78v. my charger isnt here yet so i havent got to tried. it. i didnt bother hooking up 3v and 5v leads. it does have a 10ohm 10wat sandbar across the 5v. thanks

Enticer

Your charger should work fine with that voltage. My P/S is the same and my charger works great. If you add some more resistors to the 5V side it will bring up the voltage on the 12V side.

mrasmm

yeah, that sounds alright. If you want to bring up the voltage you might try a bigger load on the 5v rail. I used 4 1 ohm resistors in series to make a 4 ohm resistor for almost 7 watts power dissipation, and my PSU runs at 12.20v under a load.

soyer

ok thanks guys. ill try adding more ressiters

cwharper

I think I've narrowed the cause of this voltage difference down to loss through the cable between the psu and triton2. While charging my high capacity lithium battery this cable does become quite warm as it is handling about 9.4 amps of current.

Gigaah

OK I've read a lot of these power supply conversion threads. Most issues revolve around This color wire..to this color wire..but my wires are colored like this or my connector is 20 pin vs 24 pin. Its gets SOOO confusing. The fact is not all manufactureres use the same color wires.
It is a fact however that ALL ATX supply connectors are wired the same to the connector. Here is my attempt to clear the air on how to wire the connector to trick the supply to turn on in the absense of a PC motherboard. I've done this on several older 200watt ATX supplies and new 500 watt supplies. So here is my diagram. Hope its done clearly enough. If I didn't fudge anything by accident I think this should be the end all and relief for most people. I think in general a 10watt 10ohm resitor is enough. If it requirs any modification let me know, we can iron out any problems with the diagram and then Mods should just sticky this particular picture for that portion of the supply conversion that hangs everyone up.