28 Mar
2005
28 Mar
'05
10:41 a.m.
On Mon, 2005-03-28 at 02:44 -0500, Ethan Dicks wrote:
On Sun, 27 Mar 2005 22:58:01 +0100, John Honniball
<coredump at gifford.co.uk> wrote:
Just to confirm - Zilog parts labelled Z0853006PSC (SCC) are the same as
AMD part AM8250H-6 ? (I would think so)
This Sun board has two AMD parts which run the four serial ports (plus a
third which looks to handle keyboard and mouse)
I've identified whch of the three on the board is responsible for the
console port (and faulty). However, I've got a Sun "Comm Processor II"
board in a Sun 3/150 which has eight of the Zilog ICs on board. We don't
need that many ports for anything, so I'm tempted to do a swap (if I
don't find a surplus AMD chip in my spares bin).
Earlier I cut the A/-B track (which selects which of the two ports on
the SCC chip to use) and diverted it via an inverter, so that when the
Sun 4/330 thought it was accessing the console port it was actually was
using the second serial line - hooked up the physical console to the
second port then, but no change in the garbled output. So basically that
confirms the the SCC chip is broken, and that the parallel - serial
conversion is common to both ports on the chip (which is
understandable). I was hoping for a quick win though :)
Time to get the desoldering equipment out I think...
cheers
Jules
There's a Zilog serial chip, quite close to
the serial connector.
If it's just bit 6 that's faulty, it sounds like a fault in that
chip (in the parallel section). I think it's a Z8530.
Suns (as well as old Macintoshes, etc.) do use Z8530s for serial
ports. Depending on the vintage of Sun, it's likely to be in a PLCC
package, though.