At 09:30 am 22/08/2001 -0600, you wrote:
There are relatively inexpensive ($20 US) multimeters
that can measure
frequency
up into the tens of megahertz that would be helpful.
If you are measuring a
clock, it will tell you right away whether it's right. It won't tell you
much
if it's wrong, though. It does give you more
information than just measuring
voltage.
I just had a closer look at mine; I bought it from Halfords (translation
for Statesiders: an auto spares/tools store) and it's got various motor
related functions (an RPM reading and dwell angle measurement thingy), but
I notice it has a frequency reading (Hz, may be a bit oversensitive for
1-2MHz), pulse width (mS) and period (mS) readings. All of these may be
unsuitable for use on a high-speed computer, but I fancy giving them a
go... It can also measure Vac, which is useful for checking transformers...
Test equipment is expensive, but hardly anyone wants
the "old" stuff that
once
was perfectly adequate for precisely this class of
equipment. A 'scope
with two
probes, delayed sweep timebase, and a bandwidth in
excess of 20 MHz (e.g. TEK
935) is probably adequate. If you shop around, you should have no trouble
finding a TEK 465 (100 MHz) that's quite complete and functional for
somewhere
on the order of $250. Over time, these will become
less available,
however. My
old '465 is still the workhorse around my place,
though I have faster,
fancier
models.
This reminds me, a place I used to work at used HP oscilloscopes, c/w
IEEE-488 bus. I don't know if it'd be possible to use a CBM8032 hooked to
an oscilloscope to diagnose a faulty 8032; but it has a nice symmetry about
it :)
As classic hardware ages, it's likely to break and you'll want to be able
to
fix
it, since the technology of the '70's and
'80's renders this stuff inherently
repairable.
It may be painful to learn, but it's very satisfying when you breathe life
into
what was a "dear, departed" computer from
yesteryear.
Definitely. And with Z80s (in particular) being so cheap, as well as DRAM
chips, building ones own becomes quite appealing too. I know a chap who
already does that sort of thing (although I think he uses older Intel
processors on the whole); but I like the idea of a 40-pin processor - it's
nice and simple.
I haven't a clue how the bus works though....
Cheers!
Ade.
--
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