-----Original Message-----
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Tuesday, November 23, 1999 9:06 PM
Subject: Re: Oscilloscopes
>> It's rare that I do. Used to have a 465B, didn't use it enough to
warrent
>> maintaining it or it's weight. While the book calls for a better scope,
>> I know the 20mhz B&K would be more than enough to track 8F core problems
>
>Sure... But if you're buying a 'scope, it makes sense to get one that
>will do all that you might need. So while you don't need a 50MHz 'scope
>or whatever to sort out 8/f core memory, you might find it worth getting
>one for other work.
>
>> as I used it to set the slice time. Then again, I know how to get the
most
>> out of a scope too.
>
>Oh sure...
>
>There are some people here (you're certainly one, I like to think I'm
>another) who (most of the time, at least :-)) understand what we're
>trying to look at and understand just what our test gear will do when
>given a strange signal. We know what our '20MHz' scope will do with a
>30MHz signal. And we know how to push the instruments a bit.
>
>You don't _need_ expensive test equipment. I've done a lot of fault
>tracing using a cheap analogue multimeter and a Radio Shack logic probe.
>And with those 2 instruments I managed to extract enough clues to the
>fault to replace the fault component first time (most of the time).
>
>However, I am also sure that there are people here who could use some
>more clues as to the fault, who can't interpret every last piece of
>information that they can get from simple instruments. And those people
>generally make use of rather more instruments, which perhaps aren't
>strictly necessary...
>
>Don't get me wrong -- there are times when _I_ find a 'scope essential.
>Perhaps if I was more clueful I'd not need one then either, but I do. But
>I've also discovered that _very_ rarely do you need a new and expensive
>piece of test gear to fix a classic computer. Most likely you can do it
>with what you already have if you think about the problem.
>
I agree but I would not recommend someone dropping a couple hundred bucks to
fix an old 20Mhz scope as I am sure they would not limit their use
*exclusively* to vintage minis. A 20Mhz scope in RF/High speed logic
troubleshooting/design is totally useless. A 20Mhz scope isn't even very
good at looking at the color burst of a video signal in any detail. Again, I
find most folks design/troubleshoot in a variety of areas and that's why we
need scopes with all the toys. I don't see Tek making any more 20Mhz boxes.
>I was discussing a related subject with a friend earlier this evening. We
>came to the conclusion that experienced hackers (this was actually about
>mechanical engineering, but it applies to electronics as well) can do a
>lot of good work using 'scrap' components and a few tools/instruments.
>But beginners probably should use new (and known-good) components and
>have rather more instruments. Of course it's often the other way round --
>beginners don't have the money to spend on a hobby they may not continue
>with, while experienced people have obtained a good collection of tools
>and test gear over the years (and really know how to use it!).
>
>-tony
>
Well thanks to the PDP-8/m, I'm finally getting around to trying to figure
out how to use my Tek 465B scope. Unfortunatly according to my Dad the
scope needs some work, I figure he should know as he retired from Tek.
With his help I did finally get some readings, not quite what I'm looking
for, but I'm fighting several obsticales. No manual, an apparently flakey
scope and you *don't* even want to know what I'm using for probes (hint,
they looked kitbashed, and I've had to extend the connectors to be able to
take readings).
End result, I'm pondering just going out and buying a new scope (which I'll
be the first person to say is really, really stupid given my electronics
abilities). Looking at what the recommended replacement for my scope is, I
see it's a TDS220, and more than I want to spend. The recommended
replacement for the scope listed in the PDP-8/e/f/m maintenance manual is a
TDS210, still more than I really want to spend, but getting closer. Does
anyone have any recommendations for good new scopes that would probably
only be used for working on DEC gear (but you never know). Ease of use,
and small size a big plus. Ideally something under $1000, or even better
$800.
Is Fry's a good place to get scopes? They've probably got the best
selection in the area that I'm aware of.
Zane
| Zane H. Healy | UNIX Systems Adminstrator |
| healyzh(a)aracnet.com (primary) | Linux Enthusiast |
| healyzh(a)holonet.net (alternate) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
<> You should be able to find a 2465 in decent shape for $1000-$1500
Youch! I do 98% of my work with a B&K 20mhz dual trace and a NLS MS15!
Most of the time I don't need more than that to see if life exists and
rough timing. I also have a Logic analyser if I need something faster.
It's rare that I do. Used to have a 465B, didn't use it enough to warrent
maintaining it or it's weight. While the book calls for a better scope,
I know the 20mhz B&K would be more than enough to track 8F core problems
as I used it to set the slice time. Then again, I know how to get the most
out of a scope too.
Allison
I don't remember a "Visual C" for DOS. There was Microsoft C which the best
version was probably 5.
There (might) have been a Visual C for Windows 3.1. I received a free copy
of Visual C++ for Windows 3.1 with Visual C++ V4, or whatever. I see copies
of those in the CD resale/software resellers around here.
I have MS C, but I think the only one I have is for Xenix....
Of course, I could be totally wrong, I can't remember.
-Mike
-----Original Message-----
From: Bill Farmer <wlfarmer(a)ancimail.prod.fedex.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Tuesday, November 23, 1999 5:40 PM
Subject: MSVC
>Do you know where I can purchase a copy of Microsoft Visual C. I do
>not wnat C++, just plain old Visual C for compiling in DOS.
>
>
>
Too bad it's the 465 "B" version. I've got an extra service manual for the
'A' version, which was the last one TEK built before simplifying their
triggering circuit. They did this because HP proved you don't have to be
able to trigger all that well.
I recently (2 years back) bought a fairly clean TEK 475A with the DM44
option and probes for the scope and the DMM for $500 by searching the
newsgroups. I still have my 465 which I bought about 20 years ago from an
instrument rental outfit. It needed a little service, and, when I took it
to TEK, I learned that it was only three months old and still in warranty,
so the tune-up was free.
The fellow who declared his "fav" is the 2465 has forgotten the size of the
difference in cost between a scope like the one I bought and that model. My
2467B was stolen in a burglary about five years ago, and, while I got my
2467 from a local aerospace contractor doing a selloff after a contract was
prematurely terminated. The 2467 equipped as mine was would have cost
about $15K leaving out the less common options, though there were fewer than
half a dozen for sale throughout the country. I should have paid closer
attention to the price changes and the ones which were sold while I was
negotiating with my insurance carrier. By the time I got a check, the
lowest-priced available 2467B was over $20k.
For fiddling with a PDP-8 you don't need a 400MHz 4-channel instrument with
GPIB, etc, with microchannel plate display amplification to help you observe
metastability in sub-10ns logic, since there isn't any (sub 10ns logic, I
mean).
If you look on DEJANEWS, you can find several guys who routinely refurbish
and resell instruments. They will send the instrument to you on approval,
and all you're risking is the odd $50 for shipping. A lot depends on what
you have sense to tell the guy you want, since that may remind him to check
things out more thoroughly.
I'd recommend you buy your probes from the guy who sells you the instrument.
They're more important than you might think, and the guy who wants to sell
his scope will be motivated to find you what you want. Be sure to insiste
that they be complete, however, because missing parts are likely to remain
so.
Dick
-----Original Message-----
From: Dave McGuire <mcguire(a)neurotica.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Tuesday, November 23, 1999 4:27 PM
Subject: Re: Oscilloscopes
>On Tue, 23 Nov 1999, Dwight Elvey wrote:
>> You can get manuals for these someplace. They are out there.
>
> For manuals try www.usimperio.com. I deal with these folks regularly
>(they're local to me) and they're very well-stocked. Tek manuals aren't
cheap,
>though...
>
> -Dave McGuire
-----Original Message-----
From: healyzh(a)aracnet.com <healyzh(a)aracnet.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Tuesday, November 23, 1999 8:40 PM
Subject: Re: Oscilloscopes
>john wrote:
>> Watch used 210s.. Tektronix recalled a huge lot of them (I think almost
all
>> of them) last year as the connection to ground was breaking off inside
the
>
>If I replace the scope I've got, I don't see me trying to cut corners again
>by getting another used scope. If I do, it will be from a reputable
dealer.
>
>> scope (Yikes!). Also, the 210 has a shitty display like my THS720A... it
is
>> LCD and rather fast changing waveforms can look like a band of black on
the
>> screen (very annoying).. The price is right and the storage is nice but
the
>> display is not anywhere near as nice as a CRT.
>
>I've got to admit I'm wondering about the quality of a LCD display.
>
I am quite sure you *won't* like it compared to a CRT... and a field of
video on it looks like garbage.
>> Best thing to do is go to your local Tek dealer and try out a TDS210 and
a
>> CRT model (maybe even a 694C ;-) ).. See which one your comfortable with
>> and then buy used if you don't want to spend the bucks.
>
>Sound advice, I figure I'd like to be able to see what I'm getting before I
>get it. However, a quick look at the Tek site has me suspecting I'm not
>going to want to spring for any more than a TDS210.
>
Then buy a CRT scope from another manufacturer. Tek is costly... or... You
could be patient, call the largest local liquidator around and get on his
mailing list. I picked up two of my scopes through bankruptcy auctions and
paid far less than what they were worth. Look for a local company going
broke that *would* need a good digital CRT scope in operations(more than you
think). You can get the list before the auction and scan for a TEK realtime.
I have turned down *many* TDS400 series scopes for less than $600US at these
auctions because what could I do with a forth scope????
Most bidders attend a food processing plant for food and machines.. not
Tektronix scopes.. and you won't find your local surplus guy bidding against
you if it is the only piece of electronic equipment they had. I take
*leaves* from work at least twice a month for auctions.
At auctions over the past three years I have found (just for interest):
IBM 1401 - went for $500 (Interhauler Yahts - Niagara Falls Area)
Basic MAI 4 - $800 (some guy thought he could use it in his company -
hahahaha)
NCR Xenix? Towers
Actually I saw another 1401 sell at "Sun Beam Shoes" in Port Colbourne (near
niagara falls) for scrap at their bankruptcy auction because they couldn't
even get a minimum bid of $200.
Too many PDPs to list.. not to mention an IBM1130 at the local school board
auction a few years ago.
>> I don't recommend throwing away a few hundred dollars on an old piece of
>> junk... you just might get another PDP-8 to fix! ;-)
>
>I like that kind of reasoning :^) I'd still like to get something like an
>-8/i one of these days, but the -8/m is better than nothing (and it's taken
>a long time just to get it).
>
I am happy you agree. I could never justify blowing $500 on a piece of junk
if I know I *really* need to spend a thousand bucks on something I can use
for a long time.
8I ????????? Hmmmmmmmmmmmmmmm. email me!
> Zane
>
On Nov 23, 21:44, Tony Duell wrote:
> >
> > ard(a)p850ug1.demon.co.uk (Tony Duell) wrote:
> > > My guess is that tifftopnm (which is what I normally use) is only
going
> > > to extract the first page as well. Anybody got a utility to pull the
tiff
> > > apart into individual pages?
> >
> > Look for tiffsplit, which I think comes with libtiff (so if you built
>
> Right... The version of the pnm tools I installed came with libtiff
> (correctly configured :-)), but not with any other utilities...
>
> However, I now know what to look for when I need to split up multi-page
> tiffs (which is hopefully not too often) -- thanks!
I thought of tiffsplit too, but I tried it on a couple of the smaller tiffs
>from highgate today -- and it choked. tiffsplit only recognises a limited
set of tags, and those tiffs seem to have at least one it doesn't like :-(
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
