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

[Paulgir]

On Sun, 24 Jun 2012 16:34:29 +1200, Stephen Worthington  
<stephen_agent at jsw.gen.nz> wrote:

> 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.
>
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A know reason for CMOS settings to go awry is a dying CMOS back up battery.
I had to replace one this week.
-Paul