# I may be putting too much on my power supply (solved)

## Bigun

I've got a 500w power supply.  It was running:

 - 4 SATA hard drives

 - two memory sticks

 - motherboard

 - 1Gbit network card

 - processor 

with no issues.

I've upgraded to a new motherboard (which doesn't have on-board video).  So the following is the new power consumption list:

 - 5 SATA hard drives

 - three memory sticks

 - motherboard

 - processor

 - 8 Mb PCI Video Card (not PCIe)

 - 1Gbit network card

Now the computer was booting fine the first few times, now only seems to stay on for about 5 seconds.... then dies and stays dead until I remove power and re-apply.  I guess it's just too much for the supply.  My questions are:

1)  Am I right about too much for the supply?

2)  If so, how high should I go?

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## BillWho

Bigun,

I find this site helpful - there are others too  :Exclamation: 

http://extreme.outervision.com/psucalculatorlite.jsp

Good luck   :Wink: 

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## Bigun

That doesn't make any sense, it says I only need a 300 watt.

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## albright

 *Quote:*   

> 1) Am I right about too much for the supply? 

 

what happens if you take out the memory sticks and 4

of the drives ... ?

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## Bigun

 *albright wrote:*   

>  *Quote:*   1) Am I right about too much for the supply?  
> 
> what happens if you take out the memory sticks and 4
> 
> of the drives ... ?

 

Still won't boot... the computer power lights stay on for about 2 seconds.... flickers sporadically, then goes dead.

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## NeddySeagoon

Bigun,

Is this new system a home made PC?

Have you had some practice at getting the heatsink compound on the CPU just like baby bears porridge?

or did you use a heatsink with a thermal pad already fitted?

You won't be getting near 500w at startup but there are several thingsto consider.

1. The start up surge - SATA drives draw about 12w active and a lot more at spin up.

2. Your PSU can't really supply 500w unless its split across the outputs exactly right, and it never is.

There will be a limit for each 12v supply (you should have 2) and for the 3.3v and 5v combined.

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## Bigun

 *NeddySeagoon wrote:*   

> Bigun,
> 
> Is this new system a home made PC?
> 
> Have you had some practice at getting the heatsink compound on the CPU just like baby bears porridge?
> ...

 

This is a custom built rig.  Then possibly a bad power supply?

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## NeddySeagoon

Bigun,

Or a bad motherboard.

Slacken all of the screws holding the motherboard into the case, to the point where the heads do not touch the board.

Does that help?

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## PaulBredbury

Are you able to check the CPU temperature in one of the BIOS' screens?

If the CPU's heatsink isn't properly mounted, with the paste doing its job, then the CPU will kill the power in literally seconds, to stop itself from melting. I've seen it myself, on a CPU heatsink where one of the 4 plastic corner connections broke, so it wasn't quite making contact.

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## Bigun

 *PaulBredbury wrote:*   

> Are you able to check the CPU temperature in one of the BIOS' screens?
> 
> If the CPU's heatsink isn't properly mounted, with the paste doing its job, then the CPU will kill the power in literally seconds, to stop itself from melting. I've seen it myself, on a CPU heatsink where one of the 4 plastic corner connections broke, so it wasn't quite making contact.

 

Before it stopped working, I checked that, the sink seemed to be doing it's job nicely.

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## Bigun

 *NeddySeagoon wrote:*   

> Bigun,
> 
> Or a bad motherboard.
> 
> Slacken all of the screws holding the motherboard into the case, to the point where the heads do not touch the board.
> ...

 

I will try that tomorrow, right now I need to step back before I throw it out my window.

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## Bigun

 *NeddySeagoon wrote:*   

> Slacken all of the screws holding the motherboard into the case, to the point where the heads do not touch the board.
> 
> Does that help?

 

Same result

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## Bigun

Ok, now I'm about 99% sure it's the power supply.

I took out the PSU, opened it up, and I see at least 3 capacitors that are leaking electrolyte from their bulging tops.  Tempted to just replace the caps.

*EDIT*

Crap, I can't.  Looks like they used some kind of hardened glue to make sure no component replacements could happen without replacing a whole glob of components.  Looks like a new PSU for me.

Also, I recounted:  4 Caps are leaking (3 from the top, 1 from the bottom), and another two were bulging.  I'm thinking it would do fine at just running idle, which it did for quite a while, but can't handle cold starts.  Probably has been this way for a while.

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## NeddySeagoon

Bigun,

PSUs need really good caps to handle the ripple current.  You get what you pay for. Look at cheap PSUs - don't expect them to outlast the warranty by very much.

Look at expensive PSUs - you don't need all the extra bling and connectors. Buy a PSU in the middle rang.  It will be made with good quality parts and have none of the eye candy.

Don't bother replacing the caps.  The failing caps will overstress other parts.

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## Bigun

Looks like that online calculator was right.  I found a spare 300 watt, put it in, and it booted up just fine.

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## eccerr0r

My server has a 300W PSU (AthlonXP2200+, 2x512MB DIMMs, 5 PATA hard drives, ATI Radeon 9250SE, RTL8169 Gbit Ethernet) and seems to work OK for the past few years of 24/7/365 use (Antec Smartpower 300).  Need to watch out for many cheap PSUs.

It's not easy to tell a cheap PSU from a good one but a layman's check: usually good PSUs are heavy for their wattage/size (for the larger heatsinks).  Also 200W PSUs are lighter than 500W PSUs.

This of course is not the definitive way to tell a crappy PSU from a good one, have to do some qualitiative checks...

Also had to mention, the bad caps tend to be the output caps from what I've seen.  I don't see too many input caps die.  When the output caps blow the downstream stuff that gets stress is ... hard disks, CPU, motherboard, RAM...

Don't buy cheap PSUs...  I'm quite impressed by the Smartpower 300, it was a replacement for a "cheap" psu I had, and has lasted much longer than I expected (and hope it keeps on working for years to come, knock on wood).  That being said, I have an Antec Smartpower 400 that died.  YMMV.

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## duderonomy

what a great thread !!!

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## eccerr0r

My Smartpower 300 just died on me :(

Apparently the fan failed and I didn't notice in time (should have made lm-sensors send mail!  It has a tach on the fan!).  The PSU roasted itself to death. 

Though the failed fan may have sealed fate but there were bad caps everywhere on the PSU board... hmm...

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## DaggyStyle

 *eccerr0r wrote:*   

> My Smartpower 300 just died on me 
> 
> Apparently the fan failed and I didn't notice in time (should have made lm-sensors send mail!  It has a tach on the fan!).  The PSU roasted itself to death. 
> 
> Though the failed fan may have sealed fate but there were bad caps everywhere on the PSU board... hmm...

 

how do you do that?

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## eccerr0r

Well, I could have just polled the sensor data and if any fan stops, then send mail...shouldnt be too hard.  I don't think there is any interrupt driven method unfortunately.

```
CPUFan:      3443 RPM  (min =    0 RPM, div = 8)

PSUFan:         0 RPM  (min =  666 RPM, div = 8)  ALARM

```

:(

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## DaggyStyle

 *eccerr0r wrote:*   

> Well, I could have just polled the sensor data and if any fan stops, then send mail...shouldnt be too hard.  I don't think there is any interrupt driven method unfortunately.
> 
> ```
> CPUFan:      3443 RPM  (min =    0 RPM, div = 8)
> 
> ...

 

I see, there is not builtin func, just a script that tests outputs periodically.

ok.

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## eccerr0r

Well, looks like the SP300 suffered from the capacitor plague too...

Found at least five unserviceable capacitors already (the PWM IC power filter capacitor, both +3.3V output capacitors, and both +5V output capacitors).  The +5VSB capacitors are also bad but not part of the protection circuitry so I'm ignoring for now.

FSCK YOU FUHJYYU (the brand of capacitors that failed)!

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