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Re: ZIP GSX 1.0.1 vs 1.0.2



Drew wrote:
On Aug 31, 9:41 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
heuser.mar...@freenet.de wrote:
On Aug 30, 8:42 am, Drew <GoggleD...@gmail.com> wrote:
Well on the back of my 2 x 1.0.1 boards there is a capacitor...maybe
thats the difference. Anyone confirm if there is a capacitor on the
back of the 1.0.2 board?
I don't have the card but a photo of the 1.02 backside and it
doesn't have a capacitor there.
Judging by ebay auctions the 1.02 seems to be much more common
than the 1.01.
If the capacitor is a small value (less than 0.01uF), then it is
used to slow down a signal that was most likely creating a "race"
condition on some cards.

If the capacitor is 0.01uF or bigger, then it is a bypass cap
that was installed to solve a power glitch problem.

Either way, the 1.02 version apparently altered the logic in
the gate array to eliminate the need for the cap--and possibly
in a way that lowered the average upper limit on card speed.
(This suggests that the cap is probably a small cap, and a race
condition was the problem it was fixing.)

Hi,

Can't make any markings on the cap, but have put a photo up:-

ftp://drewbie.dyndns.org/RearofZipgsx.jpg

The picture is too blurry to tell definitively (and the markings are
probably on the underside of the cap), but it looks smaller than 0.01uF.
I'd guess 100pF to 1000pF, and almost certainly a capacitor intended
to delay a signal rise and/or fall time by a small amount.

-michael

AppleCrate II: An Apple II "blade server"!
Home page:  http://members.aol.com/MJMahon/

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