3 Apr
2001
3 Apr
'01
12:38 p.m.
I didn't deal with DEC mauals, nor did I often deal with Heath/Zenith stuff. In
fact, Heath and Zenith hadn't "merged" by the timeframe I'm
remembering.
Nevertheless, I can remember more than one case wherein I had board revisions a,
b, and c of a given board, and the same error, on schematic revisions a, b, and
c appeared. That convinced me the mfg's were trying to "protect"
something.
It's true, the Tandy doc's that I saw were about as good as any of the time,
though the underlying designs were often about as poor as any of the time.
Dick
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Tuesday, April 03, 2001 11:49 AM
Subject: Re: D connector tirade (was: Re: Age-old ethernet equipment)
IMHO the best manuals at that time (not considering the price) were the
ones from DEC. The PDP8/e maintenance manuals in particular are almost
tutorials on computer operation. The PDP11/45 manuals aren't bad either
(things like a cycle-by-cycle description of the microcode). But DEC
manuals were _very_ expensive (although probably worth it)
Other companies had excellent manuals as well -- one that sticks in my
memory is a Philips service manual for one of their P800 series of
minicomputers that contains an entire section on the operation of the
SMPSU, complete with current and voltage waveforms for the chopper
circuit. Just what you need when you have PSU problems.
But the best _value_ manuals were Tandy IMHO. They included all the
essential information (Schematics, ROM calls, that sort of thing), and
were cheap. I can remember paying 99p (!) for the CoCo 1 technical
manual. Now, admittedly that was in a half-price sale, but even at
\pounds 1.99 it was still excellent value. I also remember getting my
Model 100, and ordering the techref for it. It cost something like
\pounds 3.99. Again, it has all the information I needed in it (I/O
connector pinouts, schematic, data on all the main chips, and so on).
To be fair, there have been some other excellent manuals for micros.
Heathkit/Zenith ones are great (or at least the ones for my Z90 are).
Although I don't much care for the machine, the Apple ][ Reference manual
is not bad. And even though Apple no longer supplied such a manual with
the //e, it was at least available as an extra (I found it in a London
computer bookshop a few years back amongst the Mac manuals. Needless to
say I bought it).
It's hard to think of a micro from before the days of PC clones where
such information was not available.
Now, alas, it's hard to think of a machine where it is.
At least with S100 stuff (say) you often had
schematics. And pinouts of
all the connectors. And data sheets for the chips. Some manufacturers
were better than others, of course, but few supplied only manuals that
were as bad as the so-called documentation you get with PC products these
days.
Both of my kit systems (Heath/Zenith Z-100 and SWTPc 6809)
have excellent manuals that go into the timing, schematics, and chip
datasheets. Tandy used to have available seperately some excellent
tech manuals on their various systems. I've got a number of them, including the nearly 400page service manual for
the Model 2000.
Osborne had a pretty serious set of tech manuals for their products
as well, the ones for the Executive spanning 5 volumes, including the
source for it's ROM monitor and BIOS. Atari did a similar manual for
the 400/800.
Ever seen the HP71 IDS? That's 3 volumes on software, 1 volume on
hardware, 1 volume on HPIL for a _calculator_. You get ROM source,
schematics, assembly language, timing diagrams, ROM calls, and lots more
information.
With most of today's systems, you're
lucky to get any kind of
manual at all. It's just as likely to be a flyer of just a few pages
as it is to be a PDF file on the system CD. Certainly nothing that
goes too in-depth into the actual hardware.
I wouldn't object to a .pdf on the CD (even though I particularly dislike
that file format) if it included some useful information. After all, if I
bought a modern machine, it would probably have a graphical display, so I
would be able to read a .pdf. And in any case I am sure I could find
somebody who would read it and print it out for me for a suitable fee.
Problem is, such manuals do not contain useful information...
-tony