[mythtv-users] Lost my OS hard drive (also ran)

[Brian Wood]

On Tuesday 15 September 2009 12:26:34 bhaskins at chartermi.net wrote:
> ---- David Brodbeck <gull at gull.us> wrote:
> > Ian Clark wrote:
> > > However, that was a trick to spin up a drive that wouldn't, clicking
> > > sounds more permanent. :(
> >
> > Not to be a pessimist, but my experience is that clicking often means
> > the servo track is damaged.  If the servo track is gone, even
> > professional data recovery places are mostly helpless to get the data.
>
> I'm not trying to highjack this hread, but I would like to share something
> that just happened to me.
>
> One of my external hard drives recently failed and the reason  was that it
> was not spinning up. After many off on cycles it did finally spin up.
> I was more that just a little ticked because the unit was  quite new and
> had very few hours on it
> .
> I had spent many hours moving files off of the drive when it finally dawned
> on me that I was not getting any data errors.
> Further examination led to finding that the line input capacitor had lost
> about 2/3 of it's rated value which had a drastic effect on the startup
> voltages. Oscilloscope traces of the +5 and +12 looked like something from
> a bad dream.. So, just one more thing to check before tossing the hard
> drive.

If that cap had lost that much capacitance it was also probably very leaky, 
and had a low ESR (equivalent series resistance), both of which will cause 
problems, possibly increasing the load on the PSU (because of the leakage).

It's amazing how many problems can be traced to a lack of clean pure DC 
feeding things.

Since most power supplies these days are of the switching type, it's harder to 
filter the inverter hash than the old 60/120 hz. hum from brute-force 
supplies.

Thanks for the tip.


-- 
Brian Wood
beww at beww.org