PSU hold-up time not enough?

June 25, 2010 at 20:57:55
What are the hold-up times for psu? if the hold-up time of a psu is more than normal, what problems could it invite? has it anything to do with the CPU core voltage? how could the hold-up time be increased in an existing psu? please answer all the questions above.

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June 25, 2010 at 20:58:54
Sounds like someone has a test coming up.

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June 25, 2010 at 21:21:52
hmmm.. the 'test' on 'psu architecture'..why..dont u have the answers? i thought these would have been the easiest for tech-guys like u.

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June 25, 2010 at 22:03:04
You know why hold up time is important? Do you know there is an industry standard for minimum hold up time? Do you know what's happening during hold up time? What components inside the psu control hold up time?

If you know the above, the other questions would be answered.

Most of us have had no formal training; I sure haven't and I know the answers. IMO your school needs either a new teacher or a new student.

Hint...what is common to every power supply on the planet?

The power grid maybe?


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June 25, 2010 at 23:09:25
hey skip i've asked some questions which should have some straight answers. but today you guys have made my post a debate topic! if you dont want to tell me the answers simply dont post anything. i want the answers desperately because i'm trying to track the source of a problem.

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June 25, 2010 at 23:32:30
OK The clue is the power grid and the danger of fluctuating current. Hold up time is controlled by capactors in the psu and has an industry standard of at least 16 milliseconds.

If hold up time is less or non existant, then yes, vCore and all other rectified voltages can fluctuate...either up or down. I doubt too much hold up time would hurt anything.

It's impratical to try and fix the psu if hold up time is a problem. Hell, it's impratical to determine if hold up time is the problem, You'd have to locate the banks of capacators and test 'em to see if they were doing their job. Normal folks just don't have the time and thousands of dollars to spend to fix a $50 psu.

So, the practical fix for suspected hold up time errors is to run out and buy a quality power supply. Same applies if the power good signal is timed wrong. You can only suspect something like that by the symptoms and I don't think I'd be very good at changing a power good signal to kick in one or two milliseconds earlier. We have no way to even properly check amperages on the various rails...that takes a lab and the equipment runs into six figures.

So hold up time gives the psu time to try and process voltage and current fluctuations. Changing old or out of spec capacators will fix it, changing capacator values would fix it too. That's all a job for the engineers who design this stuff though. In this case the wisea$$ answer is also the practical answer.

"Run out and buy a new psu."

If you google for a few minutes, you'll find sites all over the place that discuss the differences between cheapo and quality psu's, single rail vs multi rail psu's, modular vs non modular psu's, test methods, wattage rating flim flam, and so forth.


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June 26, 2010 at 02:58:26
thanks skip..i'm on the right way.
now here is the main problem..
my pc restarts on power cuts even a new APC 600VA ups is supplied. so often my data gets corrupted. what do you think replacing the psu with the one of higher wattage & price will solve the problem? i'm right now using a local one of 14 USD only!

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June 26, 2010 at 06:56:42
"i'm right now using a local one of 14 USD only!"

You've posted about your power problem several times. Why did you wait until now to tell us you only paid $14 for your PSU? You shouldn't even have to ask what the cause of your problem is!

I have a ton of bookmarks about power supplies. Here's a few that may help:

Powering Your PC: Truths and Misconceptions
A Guide To Power Supplies

Everything You Need to Know About Power Supplies

jonnyGURU power supply reviews

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June 26, 2010 at 19:10:46
because i wanted to be 100% sure about if the replacement would solve the problem or not. i've already wasted money buying 3 different branded ups including APC which did nothing for me. and i started to believe that the problem would stay forever regardless of whatever is being changed in it! but now depending on you guys opinion i'm gonna buy a new psu. lets see what it brings. thanks

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June 26, 2010 at 20:11:44
Buy a quality psu. Stop wasting money on junk. This is an example of a good one...

Audares Juvo

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