Re: Questions about the //gs

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <4kjo1h$gtn@gap.cco.caltech.edu>,
Nathan Mates <nathan@cco.caltech.edu> wrote:
> In article <barryn-0904961217510001@205.217.132.2>,
> Barry Nathan <barryn@exo.com> wrote:
> >On the ROM 0 and ROM 1 motherboards, a lot of noise interference was
> >made, and it reduced the sound quality. If you want to know what I
> >mean, try turning the volume way up, pulling down a menu slowly, and
> >listening as you go down the menu.
> 
>    That may be true for some, but on my Rom 01, that's _not_ a sound
> interference problem. To test that, I opened up my GS, and unplugged
> the internal speaker and external speakers. There was no normal way
> for my GS to make any noises. I still got the noise.
> 
>    It's a power supply thing for me, and probably others. Replacing
> the motherboard wouldn't help.

I agree.

It is most likely to be noise being induced on one of the power rails,
which is then being made audible by something in the power supply
vibrating in response to the noise.  This is also induced into the
audio amplification circuitry through the power rails.

I have noticed this sound appearing in the speaker output, along with
the noise of the 3.5" drive (especially track seeks).  The latter
could be due to increased power drain.

All of this is much cleaner in my ROM 3.

> >The ROM 3 motherboard was redesigned to reduce this problem, I think.
> 
>    Hopefully they put in a real power supply as well.

Nope.  The power supply is exactly the same, but the motherboard
doesn't draw as much power (despite having more RAM).
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand