I was in the process of converting a Sparkle power ATX power supply for use with my CB radio. The unit was running at 11.5v (kinda low?) and I decided to check the 12v yellow leads with a test light to check for higher/lower Amp rails. when I did theis I killed the unit. Now it will spin the fan half a revolution and not poer up. What did I kill, and should a test light on the 12v rail have killed it? Doesnt 11.5v seem low? Can a pot(s) be adjusted to get 13-14v? I will post a model # after work. Thank you for any and all replies.
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Sparkle power trouble
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Re: Sparkle power trouble
You likely shorted the 12v rectifier. It was likely a crappy two diodes on a bracket job given that you killed it with this little load.
An ATX supply, unmodified, has feedback dominant on the 5v rail. If you don't wish to mod that, you need a load on 5v also to keep 12v in spec.Originally posted by PeteS in CARemember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
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Re: Sparkle power trouble
Ok, it was miraculously running again today at 11.2v on the dvm. As soon as I touched the yellow and black wires to the leads in my CB, it went dead again.
It does not have a rectifier bridge, but rather a couple diodes. How much of a load would I need on the 5v rail? A 3v led work?
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Re: Sparkle power trouble
Ok If I unplug the AC cord for 5 seconds, The unit will come back on. If I apply any load the the 12 rail it powers back off. Sounds like this;
Voltage Sense Amplifier and Protection
Here is the control center of the power supply. The main feedback circuit senses the +5V output and often the +12V output as well. P/Ss also typically have circuits that monitor the +5V, +3.3V, and +12V outputs going out of regulation high. If this occurs, the circuit will latch the P/S off (cycling AC power will clear the latch condition, but if the problem cause is still present, the P/S will latch off again). There may be circuits that sense the output currents for the +5V, +3.3V, and +12V outputs that will limit the current on the output(s) and reduce the output voltages of those outputs.
Still not staying on. Unit is Sparkle Power ATX-300GT, and does have two large rectifiers.
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Re: Sparkle power trouble
Try hooking your power supply to a motherboard, hook the 12v to the CB, and power the motherboard up. Computer power supplies can power on into loads that would shut them down if connected suddenly.
As mentioned an ATX power supply is not meant to output 12v only so you shouldn't be wasting your time trying to make it work. For 5 hours at McD's you can have a 12v 20A power supply that will run your CB properly.
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Re: Sparkle power trouble
Originally posted by severach View PostFor 5 hours at McD's you can have a 12v 20A power supply that will run your CB properly.
I connected loads to the 3.3v and 5v rails (bulbs) and the light and it runs. As soon as i connect a load to the 12v rail it shuts off. It powered the CB just fine with a jumper on the green wire before I started cutting.
Does anyone know what the label on the board for the 3.3v sense wire would be?
I guess I'll just have to scrounge another PSU.
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Re: Sparkle power trouble
Originally posted by rogfanther View PostMostly I´ve seem it written "3V3 Sense". Do you still have little stubs of wire connected to the board ? Search for one orange one that isn´t in the same group as the others.
Can you post some pictures ? Maybe someone here would remember seeing them.
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Re: Sparkle power trouble
I just read this in another post and think it may be part of my problem;
The cause was most likely that tan/brown glue - it tends to go conductive over time and can short out components. This is not unique just to Bestec PSUs. IIRC, Enermax and quite a few other manufacturers use it as well. If you ever see it in a power supply, remove as much of it as you can, especially if it has turned brown.
Normally it's tan in color, but with heat and time, it turns brown and conductive.
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