|If it powered off and stayed off, that can commonly be caused by either |
A power supply problem...
- common - a defective power supply
- common with SFF computers and brand name computers in general - you have installed a video card in a mboard slot that the existing power supply has not got enough capacity to handle.
Defective or overloaded power supplies often mis-behave for quite a while before the computer won't boot at all every time you try. Did you have intermittent symptoms before this ?
If you have installed a video card in a slot , you could try removing it and connecting the monitor to the onboard video port, but the PS may already be fried if it was overloaded when the video card was installed.
Have you installed a video card in a mboard slot ?
If so, which video chipset does it have ?
OR - your cpu has overheated - eventually the mboard will shut down, and it will NOT start up until the cpu has cooled to below some temp. In that case you just WAIT until the computer has cooled some, then it will probably start up.
When was the last time you checked to see whether there was too much dust and lint on the cpu fan and heat sink inside the case ?
If your SFF mboard has a regular sized main power connector (20 or 24 pin) , it is a simple matter to try any ATX PS that has a 24 pin main connector and the proper second mboard and drive power connectors with your system - I'm assuming yours is 24 pin.
However, I found recently while t-shooting a SFF computer I suspected the PS had failed on that some SFF mboards including some of HPs have a MINI main power connector. I tried to find a mini 24 pin (male) to standard 24 pin (female) wiring adapter on the web - no such luck.
SFF PSs are almost always proprietary (oddball small sized enclosures ) and nearly always el-cheapo PSs made by minor brands.
El-cheapo PSs in general often fail because defective electrolytic capacitors were installed on their boards - they work fine for years, then the fluid inside the caps breaks down, the caps bulge on the top, they often leak fluid, and they can even EXPLODE.
My advice is, you need to open up the power supply box and look for such defective capacitors - if any are found, the PS is definitely in the process of failing. It isn't worth replacing the caps if there is a lot more than one made by the same company marking as as the one(s) that failed - you need to replace all of them made by that brand - and even if you replace all of the same brand, the PS may already be damaged such that it still cannot work properly, if your PS is not booting the computer all the way, every time you try now.
The following applies to mboards, but PSs can have defective capacitors too...
Some mboards develop this problem - electrolytic capacitors were installed on them that were not properly made, and they fail eventually - the mboard manufacturer didn't know they were improperly made at the time the mboard was made.
Open up your case and examine the mboard to see if you have bad capacitors, and/or other findable signs of mboard damage .
This was the original bad capacitor problem - has some example pictures.
History of why the exploding capacitors and which mboard makers were affected:
What to look for, mboard symptoms, example pictures:
Home page that site
- what the problem is caused by
- he says there are STILL bad capacitors on more recent mboards.
Pictures of blown capacitors, other components, power supplies, Athlon cpu's, etc.:
If your PS DOES have one or more bad capacitors, then you definitely need to replace it !
If you have installed a video card in a mboard slot....
Your power supply must have at least the minimum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD ! )
If that info is not in the ad for the video card, you can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements. Some power supplies have two or more +12v ratings - in that case, add those ratings to determine the total +12v current capacity.
If you're a gamer...
In most if not all cases, the max capacity rating of the PS is an intermittent rating. It's recommended that you do not load your PS to any more that 80% of that rating if you are going to be using something that puts a constant load on it, such as playing a recent game for hours on end. In that case, you multiply the min capacity stated for the system with the particular video chipset on the card by 1.25 to find the min. capacity of the PS you should get.
If you use the HP part number that's on the PS to search the web with, you can often find a replacement PS that will fit inside the case that has a higher capacity than one it had. However, when I looked there were none that had a capacity higher than 300 or 350 watts.
As I said above - I tried to find a mini 24 pin (male) to standard 24 pin (female) wiring adapter on the web - no such luck.
If you want to make sure there's nothing wrong with the mboard and other components, BEFORE you get another PS, if your mboard DOES have the MINI main power connector socket - in my case it was 24 pin and shorter and narrower than a regular 20 pin one - you will probably need to do what I did....
(this is tedious but the result works fine...)
- if you have, in another computer you own, or have a spare one, or can borrow, a standard sized ATX 24 pin PS (20+4)....
- buy a standard 24 pin (female) to 24 pin (male) wiring adapter with standard sized connectors at a local place ( that you normally use to EXTEND the wiring of a PS that has a 24 pin main connector (or more commonly a 20 pin and a 4 pin connector in the same wiring bundle) for use in a 24 pin mboard socket mboard (23 or 24 positions wired up on the both ends))
- chop off the wires of that wiring adapter close to the 24 pin MALE connector (you don't need the MALE connector)
- chop off the MINI 24 pin connector's wires on the failing PS as far as you can from the connector
- bare the 23 or 24 or so wires for at least 1/2" both on the MINI 24 pin (MALE) connector's wiring and the standard sized 24 pin connector (FEMALE)
- if there are two wires at some positions in the MINI connector's wiring, ignore the smaller wire - it doesn't need to be connected to a standard PS
- you do NOT need to connect the white wire if that's present on the standard connector's wiring
- cut some 1" or so lengths of shrink tubing (2 - 3 times the diameter of the insulation on the wires) and slip them on all wires on one side -
- solder the pairs of wire ends together, using electrical solder , one by one, making sure the wires go to the same place in the connectors on both ends.
- use pliers to flatten any sharp places that you can feel on the soldered splices
- place the shrink tubing pieces over the soldered splices, one by one, centered - shrink it with a hair dryer set to max or with a heat gun (e.g. for stripping paint) set to a lower setting - be careful not to melt the tubing or the wire insulation - go slowly
Plug the (male) MINI 24 pin connector into the mboard, and the 24 (or 20 + 4) pin connector(s) into the 24 pin female connector of the wiring adapter, and plug the drive power connectors into the drives.
The mboard should then boot fine if there's nothing wrong.
Side notes -
A few months ago I repaired a Shuttle SFF computer . The computer had been failing to boot the computer intermittently, and when it did boot, it shut off the mboard when booting normally if the specific video drivers had been loaded in Windows, yet it worked fine, when it booted, if the specific video drivers were not installed, and in Safe modes and in Enable mode when they had been installed.
It has a propeitary small sized PS, but the mboard and other components are EASILY tested with a standard sized ATX PS because all their SFF mboards have a standard sized 24 pin main power connector.
In that case, I replaced two failed capacitors on the mboard, the ONLY ones of that brand, and the system has been working fine since.