On 2014-05-15, Jon Anderson wrote:
Accidentally replied direct to Jon Elson, for anyone with possible
input, this was my response to him:
------------------
I'd thought maybe there was voltage, but not enough current to damage
anything. And I'd checked power with all but one drive plugged in, so
the PS was loaded.
Meter is a Fluke 8020 B, not some cheap auto-range. I'm no electronics
guru, but reasonably confident I know how to measure DC voltages. But to
prove I did it right, I went and checked the output of a wall wart.
Dang, a 13 volt supply was measuring over 200 volts! Then tried a 9 volt
battery, and it's showing 57 volts.
Ouch! Certainly a problem with the meter.
Out of curiosity -- how old in the 9V battery which runs it? If
it gets too low, readings can be quite unpredictable.
And has there been any leakage in the battery compartment? If
so, has it reached the circuit boards? If so there, pull the battery,
open it up, wash with clean water several cycles (use an old toothbrush
to clean the areas where the leakage hit, then let it dry while opened
up. (This is more than just *visibly* dry. Your heat source mentioned
somewhere in this thread is a good idaa during the drying.) (Actually,
down later in this very article, but now snipped. :-)
IIRC, your model of Fluke has a piano-key switch running along
one edge. The slightly high on the 12V and the very high on the 5V
suggests that the leakage affected the circuitry related to the 0-10V
range, and that you used a different range for the 12V measurement. In
particular, look around the 10V switch to see whether there is any
contamination in there.
I was severely weight restricted in my move, just my checked luggage
cost $500 for extra bags and overweight. So I shipped some basic tools
via USPS. Looks like my Fluke didn't survive the trip despite being well
padded. I'll go buy an inexpensive meter and see what it says about the
power supply...
I'll bet that the power supply is fine. Your original post
suggested that there was more than one drive involved. Could it be that
they are connected to different interface cables than they were
originally, so it is trying to boot off a secondary drive? (Did you
*mark* which drive was which when disassembling and packing?)
Anyway -- try swapping the drives.
Is a Fluke 8020 worth having fixed? If so, anyone know of an outfit in
AU that can (hopefully) fix it?
It probably can be fixed by the wash and dry cycle described
above. If it were a problem with a bad LCD readout, you might have
difficulty finding one to match to replace it, but this is conductance
paths, not the LCD.
Just for the fun of it -- with the probes disconnected, does it
show a voltage measurement anyway?
And as another possibility -- are you by any chance fairly close
to a radio or TV transmitter? High levels of RFI can confuse these
meters.
[ ... ]
I'd bought the 8020B maybe 10 years ago, well used. Thinking I ought to
maybe get a newer one. On eBay, I found many Fluke meters, looking at a
model 115, 233/A, and an 8060A. Want to stay right around $100, which
means used most likely. Any input on these models for someone that does
fairly basic electronics/electrical work? Or suggestions on other models?
My own favorite meter (now obsolete) is the Fluke model 27. A
bit bigger than the Fluke 77 which I first had, but it has a lower
pitched beep which I can hear for continuity tests. The 77 I had to ask
my wife to repeat the beeps when she heard them. Too high pitched for
my ears. There is another (and less common) brother to it, the model 37
has the same features, but is more set up as a benchtop meter, and has a
storage compartment for the test leads and accessories behind the main
body. (The 27 is very well sealed for use in rain and the like, the 37
is more ventilated. :-) I have both. The 27 was bought new, the 37 from
eBay. Both are autoranging, and I have no problems from that, FWIW.
Among other things, both have a LCD bar graph to take the place
of a meter needle when tuning for a null or a peak. Pure digital
readout is a real pain for that.
Enjoy,
DoN.
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