15 Jun
2006
15 Jun
'06
2:57 a.m.
Tony Duell wrote:
(grin) Agreed. I've got a Fluke 8840A and it is really hard
to NOT wait for every digit on the display to settle down!
OTOH, if I pull out my Simpson 260P, the needle ballistics
are damped enough that you get a pretty quick "feel" for what
the number is.
I have an HP set (probe and pulser) and find them quite handy!
The biggest problem is making sure NOT to accidentally let it
touch some odd supply. :-(
Of course, it really works best with traditional TTL instead
of newer logic families (but, it's good enough to give you
a quick indication of "dead" lines, etc.
There are plenty of second-hand analyesers about that are fine for
classic computer repairs. I have an old Gould 100MHz unit.
As regards using it, it depends one what you work on, but I've found it
very useful for tracing microcode in some older machines. See what the
processor is really doing (and then work out if it should be doing it).
Problem with most logic analyzers is getting all the microhooks
(or easyhooks) that go with it. Without having to sell a kidney!
On Saturday 10
June 2006 05:40 pm, Tony Duell wrote:
I would agree, but you can get away with only one when you're starting out.
For many years I used an analogue VOM only. To be honest, it's rare that
you need to make an accurate meashuremnt when repairing a classic
computer (you want to know if the 5V line is pressent and correct, but if
it's acutally 4.95V, things will still worl fine). Then I picked up a
cheap Fluke 85. I use that almost exclusively now, but the analogue meter
stays on my bench, it's better for osme things. For electronic test instruments (not including
hand tools, etc), my order
would be something like
1) A good VOM (analogue) or DMM, whichever type you prefer.
You need both! Though
I do tend to reach for the digital stuff more often than not, but
that's more a matter of physical convenience than anything
else (little teeny DMM sits on my desk AAMOF).
Tastes differ, I use one all the time. Actually, I've not used a normal
logic probe for the last 8 years or so, that's only because I bought a
LogicDart. But I debugged an awful lot of old computer stuff with a cheap
Radio Shack probe, and could do it again. 2) A logic probe
I've not found those
as useful as I'd have thought at one time. Got one here 5) A 'scope or logic analyser, depending on what
sort of work you're doing
6) The other one of those instruments
Scopes I've been using for ages, but
never had occasion to use a logic
analyzer. Or could afford one.