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walmartshopper

Tried the 0.22uF cap, power button doesn't work anymore

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I went to radio shack and got a 0.22uF capacitor to fix the switch bounce problem:

"Switch bounce" occurs when the PSU has trouble latching into the PS_ON# state as dictated by the ATX 12V 2.X specification. The internal circuitry should allow for a certain amount of oscillation in the "start circuit". If this isn't accounted for, the PSU will attempt to start then shutdown.

 

It has been determined that the addition of a 0.22uF capacitor across the start circuit can smooth out the oscillation and allow the PSU to start properly.

 

The capacitor can be added anywhere on the start circuit from the case front panel all the way to the inside of the PSU.

 

So I soldered the cap onto the start circuit, and now the power button on the case does not work anymore. The power button on the mobo does work, and it did solve the problem of the PSU starting then shutting down. So I solved one problem but created a new one.

 

The directions said "anywhere on the start circuit," so I put it on the red wire coming out of the case's power button. Was this a bad place to put it? I have a feeling it was supposed to be on the other side of the power switch.

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I was under the impression that the cap was supposed to be in parallel with the start switch. One lead on each wire.

 

You may want to do a search, but that would make sense.

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I went to radio shack and got a 0.22uF capacitor to fix the switch bounce problem:

 

 

 

 

The directions said "anywhere on the start circuit," so I put it on the red wire coming out of the case's power button. Was this a bad place to put it? I have a feeling it was supposed to be on the other side of the power switch.

 

 

The instructions should have indicated whether to install the cap parallel (across the hot and neutral leads) or in series (along one line). It sounds like you have it in series on one side of the circuit... I'm no electrical engineer, but it would make sense to install the cap across both leads in parallel, so that as it "gradually" shorts the leads, it mediates the fluctuation of power by bleeding some of it over slowly.

 

Electrical professionals, please feel free to correct and/or amplify my comments.

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I was under the impression that the cap was supposed to be in parallel with the start switch. One lead on each wire.

That would be the correct way to install it. It is now doing what it is very good at. Blocking DC voltage.

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radio shack doesn't have the best capacitors...it could very well be bad...do a search for sprague capacitors...or you could have a cold solder joint

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ok, I tried putting it in parallel, now it doesn't do anything. The power switch actually does something now, but the problem is not fixed. It still starts up for a split second then shuts down. The switch on the mobo (which worked when the cap was in series) does the same thing now. I made sure the joints were good. Maybe it is a bad cap. Luckily it came with 2 in the box, so I'll try the other one.

 

Would switching the direction of the cap do anything? I'm no electrician, but it doesn't seem like it would matter. The leads are not marked in any way to indicate a certain direction.

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As long as it's a ceramic disc capacitor, which is what you should be using, polarity doesn't make any difference.

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That's possible. The PSU I'm using for now (until I get the OCZ back) is only 480w. It has dual 12v rails, but I'm not exactly sure how that works. It's a modular PSU, but I'm not sure if the two 12v rails are somehow split between the ports or whatever. So it's entirely possible that the load is not balanced.

 

I'll just wait it out until the OCZ comes. I can still get the comp turned on if I wait for a few minutes before pressing the power button. And once it's up, it's nice and stable. So I guess I'll just leave it on unless I really need to shut it down.

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