I just examined a "Zilog Z80 Microcomputer System", Model 05-6002-05 (MCZ 1/80
60K), Serial Number 744 and an associated terminal, Dentronix Systems SCS200,
Serial Number 395. The Z80 development system looks in good shape (but needs
exterior cleaning). It has two built-in 8" FDD and it has both a terminal
port and a serial or parallel port. The matching Dentronix terminal is so
clean, it looks brand new.
The system comes with a complete set of manuals, which includes schematics of
the "mainframe" and plug-in boards. Unfortunately, there is no software
available.
The system and terminal are located in Mountain View, California and I'm
guessing a total weight of 50 lbs.
If this is of interest to you, make an offer for it directly to me - and I'll
pass that information on to it's owner.
If there are no takers, I'll likely buy it myself to keep it from going to a
scrapper (in about a week).
Cheers,
Lyle
--
Lyle Bickley
Bickley Consulting West Inc.
Mountain View, CA
http://bickleywest.com
"Black holes are where God is dividing by zero"
On Sep 30 2005, 14:59, Dwight K. Elvey wrote:
> I believe there are 4 holes that you can see in the bottom
> plate that go to empty threaded holes in the frame of the printer.
> You need to put these screws in and it will clamp the
> printer unit to the frame so it doesn't wobble around
> on the rubber mounts.
> I'd tell you what thread but my unit came without them :(
Oddly enough, I had occasion to lock down my ASR 33 last night -- it
has one hole for a transit screw, at the centre near the front, between
the rubber mounts. It takes a 10-32 screw about one-and-a-quarter
inches long, with a flat washer. The manual says that when originally
shipped, there were six screws securing the typing unit and base to the
pallet, but only that one needs to be retained for future transit.
Four other holes are used to secure the base to the stand.
--
Pete Peter Turnbull
Network Manager
University of York
>Date: Thu, 29 Sep 2005 11:55:18 -0700
>From: Eric J Korpela <korpela at ssl.berkeley.edu>
>Subject: Re: Tristate Buffer Output if Input is High-Z?
>Anyone have a datasheet for Hitachi HM511000AJP8 DRAMs? It's used in at
>least some IIfx SIMMS.
>
>What's the deal with parity on the IIfx? Is the parity bit stored off the
>SIMM? The technote
>http://developer.apple.com/technotes/hw/pdf/hw_25.pdfmentions parity,
>are there 9-chip SIMMS on the IIfx? Or is the parity stored
>on a separate RAM on the mainboard? Since your max memory is 8x(4Mx8bit bit
>SIMMS) accessed 32 bits at a time (I assume) you'd only need 1 Mbit of
>parity RAM if you do parity across 32 bits.
You are unlikely to ever see a IIfx that actually implements parity.
It was an option for the IIfx but was very rare in practice. In
virtually all cases the IIfx uses an 8 bit 64 pin SIMM with no
parity. The presence of parity on the SIMM will not affect
operation, because on a non-parity IIfx, the SIMM pins for parity
connections are NC.
A IIfx SIMM built for parity will have 1/8 more capacity. The extra
storage for parity is on each individual SIMM. The pinout for the
SIMMs is in "The Guide to the Macintosh Family Hardware". It's one
of those Addison Wesley books.
I don't have that particular datasheet on hand. But if you get one,
I'd like a copy as well. I imagine it's a pretty standard 1M X 1
DRAM chip.
>Date: Thu, 29 Sep 2005 14:01:37 -0700
>From: Eric J Korpela <korpela at ssl.berkeley.edu>
>I also notice that the table on page 2 of the technote contradicts the IIfx
>section. The table says you can put up to 128MB in a IIfx, but the IIfx
>section says the biggest SIMM allowed is 256kx8.
I think you misread that somehow. The tech note states that the IIfx
does not support 256KB SIMMs. It gives examples of memory
configurations up to 32 MB, using 4 MB SIMMs, although there's a
consistent typo in the example where megabit is written instead of
megabyte.
But the maximum memory capacity is 128 MB, using eight 16 MB SIMMs.
That was/is the maximum capacity for most of the Mac II family. The
exceptions are the original Mac II (68020 based), the Mac IIsi
(supports 16 MB SIMMs, but only has 4 slots) and the abomination with
variations known as the IIvi and IIvx.
As far as I know, there can't be 30 pin SIMMs with capacities larger
than 16 MB, because there are only 12 address pins available and 12 X
2 = 24 and 24 address bits yields 16M addresses. There aren't any NC
pins left to convert to additional address lines, unless one steals
the parity pins.
Jeff Walther
I recently acquired through the generous efforts of a member here, a
Commodore PET 2001-32B. It boots up to just garbage characters on the
screen. Any quick things I can check or a 'suspect' part? Also if anyone
knows where I can obtain a schematic for this beauty, please let me know!
Thanks
>From: "Hans Franke" <Hans.Franke at siemens.com>
>
>Am 29 Sep 2005 14:41 meinte Star Master:
>
>> I recently acquired through the generous efforts of a member here, a
>> Commodore PET 2001-32B. It boots up to just garbage characters on the
>> screen. Any quick things I can check or a 'suspect' part?
>
>It's a PET, so first thing is just to press back all chips
>firm into their sockets. Solves 98% of all Commodore problems.
>
>Gruss
>H.
>
Hi
I'll make my standard comment here. Putting
DC#4 or similar materials onto pins before
putting things back together will make a difference.
This is especially true for the power pins that
would otherwise tend to over heat because of
contact resistance.
Dwight
