21 Jul
2000
21 Jul
'00
7:45 a.m.
I was going to post this request sometime, John Fousts
post has inspired me to do it now. Anyway, I have also
recently acquired an oscilloscope (Tektronix TDS 3012)
and, while I have all the documentation and some notion
of what an oscilloscope does, I really don't know how to
bring it to bare against the several dead/flakey systems
currently in my possession. I hope this message will
start a "how to use an oscilloscope to diagnose vintage
hardware problems" thread.
Thanks,
Bill
(by the way... bills(a)adrenaline.com is now my email address)
21 Jul
21 Jul
8:17 a.m.
hi,
think of an oscope as a graphic voltmeter that plota against time.
the X axis is volts and Y axis is time.
That is along way from troubleshooting with one. To trouble shoot with one
you really need to have some idea of waht you can expect to see vs what
you actually saw. Most prints do not automatically give you that.
While a scope is handy, for fixing machines that were formerly working a
DMM and logic probe tend to be more useful. Exceptions exist like setting
hammer flight time on charaband printers or slice levels and timing for
older core stacks. The latter being adjustments rather than fixed by rules
of logic.
Allison
On Fri, 21 Jul 2000, Bill Sudbrink wrote:
I was going to post this request sometime, John
Fousts
post has inspired me to do it now. Anyway, I have also
recently acquired an oscilloscope (Tektronix TDS 3012)
and, while I have all the documentation and some notion
of what an oscilloscope does, I really don't know how to
bring it to bare against the several dead/flakey systems
currently in my possession. I hope this message will
start a "how to use an oscilloscope to diagnose vintage
hardware problems" thread.
Thanks,
Bill
(by the way... bills(a)adrenaline.com is now my email address)
10:32 a.m.
allisonp(a)world.std.com wrote:
hi,
think of an oscope as a graphic voltmeter that plota against time.
the X axis is volts and Y axis is time.
That is along way from troubleshooting with one. To trouble shoot with one
you really need to have some idea of waht you can expect to see vs what
you actually saw. Most prints do not automatically give you that.
While a scope is handy, for fixing machines that were formerly working a
DMM and logic probe tend to be more useful. Exceptions exist like setting
Hi
I tend to disagree. The order of useful tools I use are
oscilloscope, analog meter and DMM. I use the oscilloscope
as a logic probe. It has a nice little light that tells me
I have pulse and a quick look at the screen tells me the level.
I quite often work on equipment that I don't have any schematics
for. I do think one does need to have data books to know
what you are doing. In older TTL, an open to an input was
easy to see on the 'scope. Debugging problems of the data bus
are great as well, so long as you know how to effectively use
the trigger on a 'scope. If someone was to tell me that I
was going on a space trip and could only take one instrument
along I would choose a oscilloscope over any meter, logic probe
or logic analyzer. I wouldn't even give it a moments thought.
As for knowing what to see, that comes with experience. One
begins to learn what a healthy data bus looks like or how
a write strobe should look. I also trouble shoot things like
power supplies, switchers as well as analog, with the oscilloscope
as the primary tool.
While others like logic probes, I always want to see more than
it is displaying. I see the oscilloscope as a more complete tool.
It is a meter, logic probe, frequency meter and simple logic
analyzer all rolled into one.
Just my personal opinion.
Dwight
9:03 a.m.
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22 Jul
22 Jul
8:37 p.m.
On Fri, 21 Jul 2000, Tony Duell wrote:
I have the Velleman (bought new about two years ago, because it looked
Really Neat!) and an old Leader LBO-501 scope (purchased for about $25
at a flea market back in 1991).
Both work fine, although the Leader has trouble staying in sync (burnt out
valve maybe?)
Now what I really want is a spectrum analyzer. I played around with
one in an engineering class back in '86 ...
Count the Oscilloscopes.
If you have more than 5, and you're not running
a test equipment shop, then you may have vintage
hardware problems.
OK, looking around I see :
Tektronix 555, a couple of Tek 5000's, a Tek 7000 (in need of plug-ins),
a couple of Solartron CD1400s, a Velleman hand-held 'scope, an ancient
Heathkit 'scope and a large-screen Tektronix with an 8-channel mux.
23 Jul
23 Jul
8:21 a.m.
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10:38 a.m.
On Sun, 23 Jul 2000, Tony Duell wrote:
I bought it ready-built.
There are a number of diodes in this scope (good thing it came w/ the
schematic, huh). Most of the ones in the sweep circuit are type
1S1588...and one 1S2076A. There are a few of both types in the
hor. and vert. amps as well.
I have the
Velleman (bought new about two years ago, because it looked
Did you get it ready-built, or did you spend an enjoyable hour or so
soldering up the kit like I did. It wasn't hard to put together... Both work fine, although the Leader has trouble
staying in sync (burnt out
valve maybe?)
Most trigger problems are due to old germanium diodes that have failed.
Must have replaced a good number in older 'scopes over the years...
3:45 p.m.
New subject: Emulex P4000 Terminal servers - End of lifed - Free software!
Just a note to all. I have an Emulex Peformance 4000 Terminal Server I
got at auction. It came without software, and initial inquiries some
time back indicated that the software needed to be purchased from
Emulex.
Recently I inquired again of Emulex regarding this, and was informed
that all Terminal/communications servers had been end of lifed, and was
given details on where to download the Performance 4000 software.
Thought this might be of interest to others out there who might have one
of these stuck on a shelf somewhere.
I have the boot file if you don't want to have to get it from Emulex.
(The P4K works good too!)
Cheers
Geoff Roberts
Computer Systems Manager
Saint Mark's College
Port Pirie,
South Australia
geoffrob(a)stmarks.pp.catholic.edu.au
netcafe(a)tell.net.au
ICQ: 1970476
3:53 p.m.
New subject: Vax 6000 Ram and/or CPU Cards wanted in Texas.
Anyone in the Southern US (or anywhere on the NA continent really I
guess) on the list have any cards to suit a Vax 6000? Fellow from the
Netbsd Port Vax list has recently obtained a 6000-410, only to find it's
minus memory. He'd like a couple of 32 mb ram cards, and if anyone has
any T2015 400 Series cpu cards, I'm sure he'd be interested in them as
well. I have a few spares, but obviously he would prefer not to have to
import them from Australia. In addition, the machine is ex Vaxcluster,
so it has a CI interface and disk controller fitted, so if someone could
steer him towards perhaps a KDB50 and some RA7x disks, or even a SCSI
controller, that would be great. He intends to assist with the porting
of NetBSD to this platform, a worthy cause indeed......
Please contact:-
+-------------------\ /-------------------+
| Bill Bradford | www.sunhelp.org |
| mrbill(a)mrbill.net | www.decvax.org |
| Austin, Texas USA | www.pdp11.org |
+-------------------/ \-------------------+
21 Jul
21 Jul
10:47 a.m.
On Fri, 21 Jul 2000, John Allain wrote:
Count the Oscilloscopes.
If you have more than 5, and you're not running
a test equipment shop, then you may have vintage
hardware problems.
That's a relief :-) ...I only have three thus far, unless you count
the ancient rusting Dumont chasis that's overgrown with wysteria
vines, that I scavenged for parts about 15 years ago (now wishing I'd
tried to restore it). Couldn't bring myself to discard the empty
chasis, so I let Nature hide it.
--
R. D. Davis
rdd(a)perqlogic.com
http://www.perqlogic.com/rdd
410-744-4900
9:01 a.m.
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8766
days inactive
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11 comments
8 participants
participants (8)
-
allisonp＠world.std.com -
ard＠p850ug1.demon.co.uk -
bills＠adrenaline.com -
elvey＠hal.com -
geoffrob＠stmarks.pp.catholic.edu.au -
John.Allain＠donnelley.infousa.com -
rdd＠smart.net -
transit＠lerctr.org