[clug] [Offtopic] Mains voltage fluctuations

Peter Barker pbarker at barker.dropbear.id.au
Tue Sep 2 13:53:53 GMT 2008

On Tue, 2 Sep 2008, Michael Cohen wrote:

>  Are you saying that it only ever shuts down during the boot
> sequence, but if it makes it past that its solid? That might indicate

That's correct.  About the time I *think* it might be starting to draw a 
lot of current into its capacitors.  Not that I'm any sort of expert on 
these things.

> that your power supply is unable to deliver the required current. When
> the unit boots it tends to use most power and often the embedded micro
> will also check the voltage levels so if they are too low it will
> refuse to boot the system. Once you get past the initial boot the
> voltage may fall much lower with no noticable effect on the system.

Too *much* voltage would appear to be my problem, though :)  I *do* think 
it's an internal check which is failing.  Something I forgot to mention 
is that after attempting a few power-ons, the machine refuses to turn on 
*at all* until the power cord is yanked for a little while.  I think the 
machine is looking at the 251V and saying, "no thanks".

> You should test the internal DC voltage if you can to ensure its
> within specs. Does the unit have an external power pack or is it a
> built in power supply? If its external you may be able to run it off a

Internal power supply.  What I'm currently planning on doing is leaving 
the thing running until I see the mains voltage drop to ~243V, then have a 
bit more of a play.  I'll certainly open up the unit before throwing it 
away, should it come to that, but I'm not keen enough to turn off and 
disassemble a currently running unit :)

I can also consider running some *long* power cords from my running UPS - 
see if that makes it happy...

> Michael.

Peter Barker                          |   Programmer,Sysadmin,Geek.
pbarker at barker.dropbear.id.au	      |   You need a bigger hammer.
:: It's a hack! Expect underscores! - Nigel Williams

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