Kaypro 4 dead
Emory
I have some clock signals near the 3 crystals but no activity
on the CPU. No clock on pin 6.
Thanks,
Emory
P.Mingpzong
The KAYPRO is almost exactly the same design as two other old systems:
The Xerox 820 SAM (Simply Amazing Machine - ack!) and the "Big Board"
but I forgot who made that. The Kaypro and the Xerox 820s basically
bought the "Big Board" design. I had about 3 Xerox 820s twenty years
ago that I bought from their surplus store and I used a lot of Kaypros
at work back then. I found the circuits to be identical except for
layout.
If you are not in a rush, I can probably dig up some Xerox 820
schematics that will answer your immediate problem. This might be
quicker though looking for user group websites.
How about sharing why you'd be repairing a busted Kaypro?
Rich Beaudry
> Anyone know where to find a schematic of the main board?
> I have some clock signals near the 3 crystals but no activity
> on the CPU. No clock on pin 6.
>
Emory,
I have a Kaypro Tech. Manual that I can copy schematics and diagnostic
info from (no charge). The schematics are not the best quality
(shrunk to 8.5 x 11, and a copy-of-a-copy), but they are readable, and
beter than nothing. Email me off-list, and we can do the details...
Rich B.
CBFalconer
Somewhere on the web there is a complete manual available. I
believe the following is the URL, but I could well be wrong.
http://www.spies.com/~aek/pdf/kaypro/
--
Chuck F (cbfal...@yahoo.com) (cbfal...@XXXXworldnet.att.net)
Available for consulting/temporary embedded and systems.
(Remove "XXXX" from reply address. yahoo works unmodified)
mailto:u...@ftc.gov (for spambots to harvest)
Lex Cunningham
that will some day need to be restored to working condition.
Lex Cunningham
Australian Computer Museum Society(WA)
CBFalconer <cbfal...@yahoo.com> wrote in message
news:3C7288AC...@yahoo.com...
Mark Zenier
You might search to see if any of the "Microcornucopia" magazine
stuff is on the web. They sold schematics of the various boards.
(I sold my copy of that with the computer when I got rid of it).
As I remember, the clock driver was a 74HC04 chip with several of
the sections paralleled to drive the clock. It's about the only
74HC family chip in the unit.
Mark Zenier mze...@eskimo.com Washington State resident
Emory
> How about sharing why you'd be repairing a busted Kaypro?
Out of space and moving soon. Thought I'd put it on eBay and
get a home for it.
E
Emory
Lee Hart
I have many of the Kaypro schematics. Can you provide a more exact
description of the board (part numbers, etc.)?
--
Lee A. Hart Ring the bells that still can ring
814 8th Ave. N. Forget your perfect offering
Sartell, MN 56377 USA There is a crack in everything
leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
Ol' Bill in Tucson
wrote:
>The KAYPRO is almost exactly the same design as two other old systems:
>The Xerox 820 SAM (Simply Amazing Machine - ack!) and the "Big Board"
>but I forgot who made that.
well, okay, so far ......
> The Kaypro and the Xerox 820s basically
>bought the "Big Board" design.
In fairness to Jim Ferguson, Kaypro STOLE his design. Xerox, on the
other hand DID pay him for the use of it.
> I had about 3 Xerox 820s twenty years
>ago that I bought from their surplus store and I used a lot of Kaypros
>at work back then. I found the circuits to be identical except for
>layout.
That's about the gist of what Jim's been saying for about twenty years
Just to try to set the record straight....
Jim designed the Big Board, for a partnership he was in that included
(among others) Bill Sigmund. Jim was the design guy. Most of the
others seemed to be marketing/money guys. The Big Board used
an 8080.
Then a principle in what later was called Kaypro bought a couple
of his units, later the copies showed up as the Kaypro. Xerox wanted
a quick entery into Personal Computing, and bought the rights to what
they later called the 820. Jim again, in partnership with others,
designed the Big Board II, which used a Z-80, included a SASI
interface and an EPROM programmer, DMA, and virtually every Z-80 bell
and whistle Zilog ever thought of. The handle for bankswitching
allowed others to hang megabytes of RAM onto the BB II.
Along with maybe 20 other members of the Minneapolis CP/M
User's Group, I put a couple together when they first came out.
I think I counted over 3,000 solder connections. Both fired right up
The Big Board II is probably the most powerful Z-80 computer
ever made, at least in 'factory standard' configuration.
Bill
Tucson, AZ
Dave Tweed
> Jim designed the Big Board, for a partnership he was in that included
> (among others) Bill Sigmund. Jim was the design guy. Most of the
> others seemed to be marketing/money guys. The Big Board used
> an 8080.
No, both the Big Board and the Big Board II used the Z80.
-- Dave Tweed
Jeff Jonas
>of his units, later the copies showed up as the Kaypro. Xerox wanted
>a quick entery into Personal Computing, and bought the rights to what
>they later called the 820. Jim again, in partnership with others,
>designed the Big Board II, which used a Z-80, included a SASI
>interface and an EPROM programmer, DMA, and virtually every Z-80 bell
>and whistle Zilog ever thought of. The handle for bankswitching
>allowed others to hang megabytes of RAM onto the BB II.
I'm confused: I have some genuine Xerox 820-IIs but there's no
SASI or EPROM programmer and they were only 64k.
Where were the SASI and EPROM programmer added?
I saw only one slot and I think that was for an optional
hard disk controller of which I have none.
>Along with maybe 20 other members of the Minneapolis CP/M
>User's Group, I put a couple together when they first came out.
Were these special add-ons in addition to the Xerox 820, or his own version ?
>I think I counted over 3,000 solder connections. Both fired right up
I once bought the motherboard for a Bigboard with the EPROMS,
schematics and notes. Before I tried ordering all the parts and
soldering it myself, the Xerox 820-IIs went surplus at a price that even
made me say "why bother with the assembly when I just want a working computer".
I wound up buying several 820-IIs from several sources, winding up with
stacks of looseleaf binders with schematics, diagnostics and such.
>The Big Board II is probably the most powerful Z-80 computer
>ever made, at least in 'factory standard' configuration.
But the CPU speed was not even 4 MHz, was it?
That's why I bought a Servo-8 single board computer:
6 MHz Z80-B at a time when the Ampro littleboard was only 4 MHz
(handled 8 floppy drives and SASI too!).
--
Jeffrey Jonas
jeffj@panix(dot)com
The original Dr. JCL and Mr .hide
Clarence Wilkerson
board "somewhere".
--
Clarence Wilkerson \ HomePage: http://www.math.purdue.edu/~wilker
Prof. of Math. \ Internet: wil...@math.purdue.edu
Dept. of Mathematics \ Messages: (765) 494-1903, FAX 494-0548
Purdue University, \
W. Lafayette, IN 47907-1395 \
Arndt Oevermann
LH> I have many of the Kaypro schematics. Can you provide a more exact
LH> description of the board (part numbers, etc.)?
Are these original KAYPRO documents? I'm interested, too.
Gut Goan
Arndt
... No Keyboard found, Press F1 to RESUME
___ QWKRR128 V5.10 [R]
Ol' Bill in Tucson
You're right - I never had a Big Board I, but obviously the
Xerox 820 and the Kaypro used Z-80s, so if I knew what I
was talking about I'd have remebered at least that much
oh well must be old timers disease acting up again
Bill