Intermittent (power?) issue with HD

I have an issue where my boot drive (Western Digital 320 GB) is not
recognized my BIOS...but only sometimes. When it seems to happen is
when my PC has been turned off for a while....for example, I used my PC
all day yesterday and turned it off last night at about 5pm, but when I
turned it on this morning, the drive was not recognized. What I've
done to "fix" it is, with the PC power off, disconnect the drive's
power connector, reconnect it, reboot and then the drive is recognized
and everything is fine. Other times when this has happened, I've not
only disconnected/reconnected the power, but I have also reseated the
IDE cable on both ends thinking that it was an issue there, but I think
I have it narrowed down to some sort of power issue because of my
latest experience where all I did was disconnect/reconnect the power
connector. SMART shows that all is well with the drive and I've tried
different power connectors with the same results. If I shut the PC
down after it being on for a while and then restart, all is fine...the
problem only seems to happen when the PC has been turned off for a
while.

Any ideas? I'm thinking perhaps I need a new power supply?

TIA!
Bob

Bob wrote:

I have an issue where my boot drive (Western Digital 320 GB) is not
recognized my BIOS...but only sometimes. When it seems to happen is
when my PC has been turned off for a while....for example, I used my
PC all day yesterday and turned it off last night at about 5pm, but
when I turned it on this morning, the drive was not recognized. What
I've done to "fix" it is, with the PC power off, disconnect the
drive's power connector, reconnect it, reboot and then the drive is
recognized and everything is fine. Other times when this has
happened, I've not only disconnected/reconnected the power, but I
have also reseated the IDE cable on both ends thinking that it was an
issue there, but I think I have it narrowed down to some sort of
power issue because of my latest experience where all I did was
disconnect/reconnect the power connector.

SMART shows that all is well with the drive and I've tried
different power connectors with the same results. If I shut
the PC down after it being on for a while and then restart,
all is fine...the problem only seems to happen when the
PC has been turned off for a while.

Any ideas?

Looks like there its a cooldown problem somewhere.

When the system cools down enough, something isnt
making proper contact. Fiddling around with the power
connnector likely just gives it enough time to warm up
and you will likely find its not the fiddling with the power
connector thats fixing it, its just the time that its on for etc.

If it is that, its usually a bad physical connection. Unfortunately
that can be anywhere that affect the hard drive, the hard drive
itself, the motherboard connector area, or the power supply.

The only real way to work out which it is is to test that
carefully. Try the drive in a completely different system
not even using the ribbon cable if you can easily.

It might be the ribbon cable and its cheap to try another.

I'm thinking perhaps I need a new power supply?

It certainly can be that and its easier
to try that than a new motherboard.

Previously Bob wrote:

I have an issue where my boot drive (Western Digital 320 GB) is not
recognized my BIOS...but only sometimes. When it seems to happen is
when my PC has been turned off for a while....for example, I used my PC
all day yesterday and turned it off last night at about 5pm, but when I
turned it on this morning, the drive was not recognized. What I've
done to "fix" it is, with the PC power off, disconnect the drive's
power connector, reconnect it, reboot and then the drive is recognized
and everything is fine. Other times when this has happened, I've not
only disconnected/reconnected the power, but I have also reseated the
IDE cable on both ends thinking that it was an issue there, but I think
I have it narrowed down to some sort of power issue because of my
latest experience where all I did was disconnect/reconnect the power
connector. SMART shows that all is well with the drive and I've tried
different power connectors with the same results. If I shut the PC
down after it being on for a while and then restart, all is fine...the
problem only seems to happen when the PC has been turned off for a
while.

Any ideas? I'm thinking perhaps I need a new power supply?

The power cables are very unlikely to be the reason. HDDs monitor
voltage levels, since they need to rescue the heads when power goes
down. The PSU is a possible candidate. If you are sure about
the on/off/time pattern, then I think the primary suspect is the
PSU. The "needs to run for some time until it works reliably"
symptoms are typical for older capacitors that are failing. They
have lost capacity and regain some of it after power has been
applied for some minutes.

Arno