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From: Theo <theom+news@chiark.greenend.org.uk>
Newsgroups: comp.sys.raspberry-pi
Subject: Re: Homebrew pi400
Date: 11 Dec 2024 18:10:07 +0000 (GMT)
Organization: University of Cambridge, England
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References: <87v7wgw3sh.fsf@rpi3> <87v7vr40jj.fsf@rpi3> <vjalsu$t70o$1@dont-email.me> <lrt4p1Fbu46U2@mid.individual.net> <87msh243xg.fsf@rpi3> <lrtr8nFf5hkU1@mid.individual.net> <87wmg6qi9o.fsf@rpi3> <vjcg53$1k27r$6@dont-email.me>
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The Natural Philosopher <tnp@invalid.invalid> wrote:
> On 11/12/2024 16:46, Daniel wrote:
> > Andy Burns <usenet@andyburns.uk> writes:
> > 
> >> Daniel wrote:
> >>
> >>> Jeff did a teardown on his second channel and soldered a m.2 socket
> >>> hoping it was properly designed. He found the power lines weren't traced
> >>> in so no power.
> >>
> >> There were some nearby component missing too, maybe the Rev1 board has
> >> bugs, and they need a Rev2 (or whatever) but his soldering job looked
> >> relatively clumsy (bridged pins etc).
> > 
> > Yeah, it was pretty bad, at least he was honest about it.
> > 
> > I am sure things were missing to keep the circuitry disabled and I'm no
> > engineer.
> 
> Why would you put support chips on if you were not going to install an 
> M.2 socket anyway?
> 
> I think he called it right in that this is a bare bones model, and more 
> upmarket versions will emerge in due course.

Looking at:
https://www.jeffgeerling.com/sites/default/files/images/pi-500-m2-socket-install.jpg
https://www.jeffgeerling.com/sites/default/files/images/pi-500-pcb-bottom.jpeg

I think there's a MOSFET and some decoupling capacitors missing (to the left
of the middle larger hole), so the power isn't connected.  There may be a
pair of missing capacitors in series with the PCIe lane, but I can't
immediately see the footprints for those.

Theo