[mythtvnz] Looks like my system drive is faulty - ideas?

[Stephen Worthington]

On Sun, 24 Jun 2012 15:19:36 +1200, you wrote:

>On 24/06/2012, at 2:59 PM, Stephen Worthington <stephen_agent at jsw.gen.nz> wrote:
>
>> On Sun, 24 Jun 2012 13:55:42 +1200 (NZST), you wrote:
>> 
>>> 
>>> On Sun, June 24, 2012 1:31 pm, David Moore wrote:
>>>> My system won't boot today unless I unplug the boot drive. Can't even
>>>> get into the BIOS setup. Just hangs with no POST beeps/messages and the
>>>> hdd led permanently on. So I can't boot into a cd to try and
>>>> diagnose/repair the drive. I can boot a cd if I disconnect the boot hdd..
>>>> Any ideas how I can get round this so I can try and fix the boot drive?
>>> 
>>> Is it IDE or SATA?
>>> 
>>> If its sata an option might be an external USB -> SATA adapter so you can
>>> try to access the drive on another system that has already booted.
>>> 
>>> Steve
>> 
>> SATA is normally hotswap, so you can unplug the drive, boot from CD
>> and then plug it in and see what happens.  But if it is preventing the
>> system from booting into BIOS, then it is likely pulling down the
>> power supply, so plugging it in may just shut the PC down again.  I
>> would recommend unplugging as much of your PC as you can when trying
>> things that are killing the power supply.
>> 
>Didn't know that. Thanks. Pulled the SATA lead and boot goes as normal up to the point that my bootable (I thought) cd didn't. So it's not a power problem at least. Must be something hanging the SATA controller.

Lots of possibilities at that point.  First, I think you need a "known
good" bootable CD - is there another PC you can try booting yours in,
just to make sure?  A laptop?

Once you have a bootable CD, if it still does not boot in the MythTV
box, I have found that sometimes the CMOS BIOS settings can go astray
for no known reason, so try using the clear CMOS jumper on the
motherboard and setting everything up again.  Even if the settings
seem valid in the BIOS screens, there can still be something bad
requiring a full clear of the entire CMOS RAM.  And I would make sure
that anything that can be unplugged from the PC is - basically
everything except the CD drive and the video card.

It could still be a power problem too - I have seen situations where
the 12 V was the problem, and had gone faulty a while ago.  But hard
drives will typically still work without proper 12 V power while they
are still rotating.  They draw on the 5 V electronics rail through
their circuit board, getting enough power to the drive motor to keep
it rotating and the heads working just fine.  But they are unable to
start up without proper 12 V, so everything seems fine until the next
reboot.  So swapping in another power supply if you have access to a
suitable one would be a good thing to try at some point.  Failing that
or a power supply tester, if you have a multimeter, find one of the
Molex connectors for IDE drives and check the voltages on them.