HDD sporadically not recognised

July 27, 2011 at 20:03:56
Specs: Windows 7, 6gb ddr2, intel E6600
Hi all,

I have a strange problem with my desktop PC. I have four internal HDD's (one being dedicated to windows only, the remaining three are used for storage). Other info: 850W coolermaster PSU, gigabyte EP35DS3 mobo, 6gb ddr2 ram (2x2 and 2x1), radeon 6950HD gfx.

My problem is that my 2TB SATA2 drive (about 3 weeks old! very new) just randomly decides not to work. In other words, sometimes when I boot up, it is not recognised in BIOS or shown in my computer/device manager. Most of the time it is, and everything works fine. The OS does not boot from this drive so obviously I can boot up as normally whether it is recognised or not. I have tried using different SATA cables, different power connectors for the HDD and neither have helped.

My question is WHY would this happen? why would a HDD sometimes show up and not others, seemingly with no difference in what I'm doing with the computer?

Thanks :)

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July 28, 2011 at 05:08:35
Cold boot or warm boot or both?
If you have a delay option for the HDDs in the BIOS, use that to start them sequencially instead of all at once.
Put a meter on the power leads. You may have one drive really sucking down the juice at power up.
It could be that one drive has a spinup issue.

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July 28, 2011 at 15:26:38
I have had trouble with SATA power connectors at times. Clean and re-insert your HD connectors a few times (to get rid of any oxide).

Always pop back and let us know the outcome - thanks

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July 31, 2011 at 03:02:44
thank you for your help guys. I don't know what a warm boot is (sounds comfortable!). I'm starting to suspect my 2TB drive is faulty, as it now no longer is recognised even after a reboot (shows up in BIOS sometimes, though). Might start to focus on it being a hardware problem rather than thinking it might be a software issue with windows 7... but it is pretty convenient that it only started happening to the drive after I installed 7.



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Related Solutions

July 31, 2011 at 08:35:21
Yep, anything odd in BIOS (such as HD's vanishing) cannot be a Windows issue and is almost always hardware. If it's not plugs and sockets then the HD itself is a likely culprit.

Sometimes coincidences happen and add confusion to the issue.

I doubt it will help but you could unplug the mains plug then hold down the "power on" button for about 30 secs. This discharges the capacitors and therefore resets anything stored in the chips.

Always pop back and let us know the outcome - thanks

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July 31, 2011 at 13:00:11
Some bioses have a setting that allows you to change the amount of time the bios takes (waits) to detect drives - if your bios has that, try setting it to a longer time.

Check your SATA data cables. The connector on each end should "latch" into the socket on the drive and on the mboard, or on the drive controller card - it should not move when you merely brush your hand against it near the socket - if it does, mere vibration can cause a poor connection of it - use another SATA data cable that does "latch", or tape the connector in place.
(There is a slight projection or bump on one side of the outside of the connector that "latches" it into the socket - it's easily broken off or damaged)

The same thing applies for the SATA power connection.

"Clean and re-insert your HD connectors a few times (to get rid of any oxide)."

If the contacts are gold plated they can't have oxide. However, they can have been contaminated with something else.

If you have any IDE drives....

It is common to un-intentionally damage IDE data cables, especially while removing them - the 80 wire ones are more likely to be damaged. What usually happens is the cable is ripped at either edge and the wires there are either damaged or severed, often right at a connector or under it's cable clamp there, where it's hard to see - if a wire is severed but it's ends are touching, the connection is intermittent, rather than being reliable.
Another common thing is for the data cable to be separated from the connector contacts a bit after you have removed a cable - there should be no gap between the data cable and the connector - if there is press the cable against the connector to eliminate the gap.
80 wire data cables are also easily damaged at either edge if the cable is sharply creased at a fold in the cable.

Try another data cable if in doubt.

"850W coolermaster PSU"

A friend of mine had a 600 watt Cooler Master PS.

I noticed the top of the case above the PS was getting really hot when I was working on his computer to get rid of some software problems.
I found that the single 120mm fan in the PS was not spinning at all. I temporarily mounted a case fan behind the fan opening to suck the air through the PS until I had finished fixing the software problems, that cooled it okay, and then I got a case fan of the same size with dual ball bearings and at least as good a rpm and cfm rating and replaced the fan inside the PS .

I looked up the PS model on the web, and found it had only a 1 year warranty - that info was in ads on the web, not on the Cooler Master web site. The fan had failed to spin after less than two years of relatively light use - it probably has two sleeve bearings rather than two ball bearings or better.
I found many mentions on the web of Cooler Master PSs that had failed due to the fan failing and the PS overheating and being damaged because of that, or because of there being defective capacitors on their boards.

A short time later, the same PS failed to fully boot the same computer - probably due to the PS having overheated for who knows how long and being damaged because of that before I had replaced the fan. I replaced the PS with a better one and the system has worked fine since.

I no longer recommend Cooler Master PSs .


Many power supplies have more than one +12v output section - if so, that is shown on it's label.

If it has more than one +12v output section, one is for the mboard, another for the drive power connectors.
Rarely, one section of the board inside the PS malfunctions such that one of the +12v sections is malfunctioning or is not working at all.

E.g. We had a guy who had put together a brand new system with a brand new PS who started a Topic here not long ago who was getting no +12v power at all to his SATA drives.

The only way to check for that may be using a voltmeter or multimeter to check the +12v power at the power connectors to the drives, although some bioses may show more than one current +12v reading.

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July 31, 2011 at 16:01:55
thank you very much guys. I'm now 100% its a hardware issue because I checked BIOS again this morning and saw that ch1 (the 2tb) was listed as BzBzBzBzBzBzBzBzBzBzBzBzBzBz instead of the WD model number. I bought all new SATA cables yesterday and replaced them and now I'm at the stage where I can get the 2TB drive to show up when the system is booted up (having used a new SATA cable), but also I have left the other two 1TB drives disconnected. I will now systematically:

- see if the 2TB disappears as it is now (only drive plugged in apart from 80GB). if this succeeds without problems,
- plug in each 1TB drive separately and see if any problems arise after a few hours use (with new SATA cables)

Thanks for the info about the PSU. What PSU would you recommend instead?


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July 31, 2011 at 19:15:10
How to make do....

If you frequently check whether the fan is exhausting warm air at the back of the PS, and check it's voltages periodically in the bios, especially +12v if it shows more than one of them, you'll be able to tell if it's on it's way out.
Voltages should be within 10% of the nominal voltage, or less.

You can install a hardware monitoring utility in Windows and have it set to warn you when the voltages are out of whack.
Retail mboard models often have such a utility on the mboard CD.
Freeware third party utilities are available on the web, e.g. SpeedFan, but you may need to tweak them to read the same as in the bios, you may need to change which reading is for what, and they may show readings for sensors that are not hooked up - the reading may be impossible (e.g. - negative rpm) and it never changes.

If the PS has one fan, or if it has two fans the one at the back of the PS, it usually has NO wiring and connector for an rpm. readout that you can connect to a mboard fan header.

Replacing the PS fan before it fails is a cheap fix and good insurance.
If you replace the one fan, or if it has two fans, if you replace the one at the back, with a case fan with two ball bearings or better that moves about the same amount of air - the rpm and amperage drawn are similar, or better (more rpm or more current drawn) - you then have wiring and a connector from that you can connect to a mboard fan header, and you can monitor that fan's rpm. E.g. the Antec 120mm dual ball bearing variable speed fan I bought for my friend''s Cooler Master PS cost less than $15 locally.

However, opening up the PS case voids it's warranty, if it's still under warranty.

Don't buy an el-cheapo PS.
See response 3 in this:

If I mentioned Cooler Master PSs in that, ignore that.

Personally I prefer Enermax PSs because they're high quality and cheaper than the higher line of Antec PSs (of the two lines, longer warranty) where I am. The fan at the back of the PS has dual ball bearings.
I have bought at least a half dozen of them for my computers and other people's computers, the oldest is now about nine years old, and none of them have failed in any way.
At least two of them have been used many hours nearly every day, by me.

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