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Re: Yes : PC-Chips' mainboards lack polyfuse

Subject: Re: Yes : PC-Chips' mainboards lack polyfuse
From: "Inty Trashtronics \(r\)"
Date: Tue, 19 Jun 2007 22:01:38 +0200
Newsgroups: uk.comp.homebuilt


"Johnny B Good" <jcs.computersbutt@xxxxxxxxxxxxxxxx> ha scritto nel 
messaggio news:31303030373730364676F03438@xxxxxxxxxxxxxxxxxxx

> You're probably right which would put that header layout firmly in the
> "Heinz 57 Varieties" camp.

The problem is that i don't know if it is an USB or something else!
No mention of it on the manual, nor on the board.

> It's a  , isn't it? Time to dig out the multimeter and buzz out
> what pins are 5 v and what pins are 0v. As long as the 5v and 0v pins
> are correctly wired, you can guess the data pins without hazarding the
> test usb gadget.
>
> There's plenty of talk about USB power being restricted to an initial
> maximum of 100mA until the extra 400mA's worth has been negotiated for
> by the attached device but, even today, the 5v pins seem to be simply
> directly connected (hopefully via a 3A polyfuse :-) to the MoBo's 5v
> rail.
>
> In most cases, it's possible to positively identify which is 5v and
> which is 0v out of the USB header pins by testing resistance to the
> appropriate pins on a spare molex with the system disconnected from
> power (the least hazardous way to probe around the innards of a PC with
> test meter leads). Incidently, the data lines look like very high

About a year agoi was measuring tensions in the output of a 15' monitor's 
power supply.
I forgot the tester on the OHM scale... it was making sparks and i didn't 
understand why.
luckily the multimeter wasn't damaged...



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