Hard drive power lead question

[Jon]

I am no hardware expert, as you will soon observe.

Turned on one of my computers this morning and it would not boot. It had
been working fine the previous day, with no changes. The hard drive was not
even detected in the BIOS, although the cdrom was.

Took off the case, and swapped the power connector to the hard drive for one
of the spare ones, and now the computer boots. Everything hunky-dory. A case
of a failed power connector. Or so it seems.

I also noticed that the power connector, for which it was not working,
seemed to be linked to the cdrom. So I'm wondering whether it's better
practice to use a power connector for a hard drive, that is not also linked
to any other device, and whether that may have lead to the problem.

Alternatively is it more likely to be symptomatic of a hard drive close to
the end of its life, or some other cause (like a failing motherboard, CMOS
battery etc)? Thanks.

Jon

 

[Guest]

I am no hardware expert, as you will soon observe.

Turned on one of my computers this morning and it would not boot. It had
been working fine the previous day, with no changes. The hard drive was not
even detected in the BIOS, although the cdrom was.

Took off the case, and swapped the power connector to the hard drive for one
of the spare ones, and now the computer boots. Everything hunky-dory. A case
of a failed power connector. Or so it seems.

I also noticed that the power connector, for which it was not working,
seemed to be linked to the cdrom. So I'm wondering whether it's better
practice to use a power connector for a hard drive, that is not also linked
to any other device, and whether that may have lead to the problem.

Alternatively is it more likely to be symptomatic of a hard drive close to
the end of its life, or some other cause (like a failing motherboard, CMOS
battery etc)? Thanks.

I connected a fan to a drive power cable and the fan ran OK, but a drive on
the same power cable was not detected. Swap the cables back and see if the
drive works OK. If it doesn't, its probably the CD. If it does, it might just
have been loose.

 

[Jon]

I connected a fan to a drive power cable and the fan ran OK, but a drive
on
the same power cable was not detected. Swap the cables back and see if the
drive works OK. If it doesn't, its probably the CD. If it does, it might
just
have been loose.

Thanks for your response.

From that, it does sound like having 2 different devices on the same power
cable can sometimes cause problems for one of them. So thanks for confirming
that possibility.

Yes, it did occur to me that I may have jogged the machine in some way and
hence loosened a power lead. The odd thing is that what seemed like the
same problem occurred a few months back, and doing what you suggested solved
the problem at that time ie I opened up the machine - unplugged and
replugged in a few power connectors, making sure that they were all tight,
and the machine then booted fine. Not this time though, unfortunately. Had
to swap the power lead for one of the spare ones to get it to work.

Am thinking of adding a new hard drive to the machine in the near future, so
may experiment a bit more with it at that stage. Thanks again.

Jon

 

[Guest]

Not, unless one of the devices is a dead short the electrons don't care. You
have a bad connector plain and simple. I have 4 and 5 devics daisy chained on
one cable. Maybe you are using a ps not rated for your board & cpu, or not
enogh watts like trying to run a p4, a couple of drives, pci cards, and
memory off a 150 watt micro atx power supply.

If everything is rated ok, and as I stated one device isn't a dead short or
clse to it, the one device shouldn't affect the others operation. It's simply
+5 volts dc, and +12 volts dc on that connector. Nothing fancy.

Brian

 

[Guest]

The ps only sees a load, it doesn't see individual devices. The devices don't
see one another either, at least not from a power perspective. If there was a
dead short the supply would only see the short and not turn on the whole
system. If you had a short you would have never even been able to power up.
Computer power supplies are protected by feedback loops for over and under
voltage & current both on the input and output.

Brian Vagnoni

 

[Jon]

Hi Brian. Thanks for that. Very informative.

Think you are right about it being a faulty power connector.

Popped in an extra hard drive this afternoon, into the computer - on another
power socket - and it's taken that perfectly. Both drives + the cdrom
working fine, using different power connectors (but avoiding the faulty
one).

The power connector had perhaps been on gradual decline for a while, since I
had a similar problem in January (although it had worked fine since then,
until today). Will just have to remember to avoid that particular power
connector in future.

Thanks again

Jon

 

[Guest]

Just get yourself a label, write BAD on it and wrap it around the power
connector.

 

[Ted]

Hi Brian. Thanks for that. Very informative.

Think you are right about it being a faulty power connector.

Popped in an extra hard drive this afternoon, into the computer - on
another power socket - and it's taken that perfectly. Both drives + the
cdrom working fine, using different power connectors (but avoiding the
faulty one).

The power connector had perhaps been on gradual decline for a while, since
I had a similar problem in January (although it had worked fine since
then, until today). Will just have to remember to avoid that particular
power connector in future.

Thanks again

Jon

Pin corrosion is another possibility. Scraping the contacts and/or spraying
contact cleaner may help if that is the problem.
Ted

 

[Jon]

Pin corrosion is another possibility. Scraping the contacts and/or
spraying
contact cleaner may help if that is the problem.
Ted

Some good suggestions. Thanks to all.

Jon

 

[Andy]

Hi Brian. Thanks for that. Very informative.

Think you are right about it being a faulty power connector.

Popped in an extra hard drive this afternoon, into the computer - on another
power socket - and it's taken that perfectly. Both drives + the cdrom
working fine, using different power connectors (but avoiding the faulty
one).

The power connector had perhaps been on gradual decline for a while, since I
had a similar problem in January (although it had worked fine since then,
until today). Will just have to remember to avoid that particular power
connector in future.

You can fix problem connectors by using a contact extractor (W-HT-2054
STD For .093 Pins, <http://www.action-electronics.com/molex.htm>) to
remove each socket contact from the connector housing, then plug it
onto a mating power pin on the hard drive, and if it feels too loose,
use pliers to squeeze the socket contact so it fits tighter.