[Asterisk-Users] Asterisk Maintenance

[Chris Glover]

On Wed, 8 Dec 2004, Michael Welter wrote:

>> Check the mains supply, there might be something with a big inductive 
>> load, that causes some ripples that are ending up on the DC outputs of 
>> your PCs PSU.
>> 
>> HTH
>> 
>> Chris
>> 
> This was a situation where I had to recover the root password, so I wasn't 
> able to ssh into the box.  I had to power-down the box, recover the password, 
> and then reboot.
>
> Also, the box is on a UPS, so I'm assuming the AC power is generated from the 
> battery and is a perfect sine wave.  But that begs the question:  does a UPS 
> system connect the mains to the output, or is the input power used to charge 
> the battery, and the battery used to generate the output power?
>

Depends on the UPS, if it's a little one (like the ones a little bigger 
than a car battery), it's all electronic, so there is the possibility of 
nasty signals getting through. If it's a big industrial rotary UPS, then 
this wont be a problem. This is where having separte "Clean Earths" cme in 
usefull.

I've know a failry big (as in size of an american fridge) electronic UPS 
put nasty 10KHz hum onto it's incoming mains. This is a bad thing when 
it's at a TV studios... upset a lot of people that day :-)

HTH

Chris

-- 
Chris
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