4 May
2004
4 May
'04
4:19 p.m.
That's what you'd think but it isn't the
case. 9825s in paricular are
nearly indestrucable but I have constant problems with all of the 9845s.
In 1979 I did a data-logging project at the Hanford Nuclear Reservation in
central Washington. We had 6 or 7 trailers that collected ground water
measurement on HP 9825s (using the built in tape drive.) The measurement
equipment was connected via HP-IB.
The power was from a mobile generator. Every time the air conditioner
started the line voltage would dip about 25 volts.
This test ran for over a year with out a single failure. I was impressed.
In the spring of 1980 the place was thick with grasshoppers. They would get
into the equipment it you let them. After Mount St. Helens dumped a foot of
ash on the place there wasn't a grasshopper to be found.
Michael Holley
www.swtpc.com/mholley
5 May
5 May
1:22 a.m.
My favorite story is about the badly beat up 9825 that I found in a
large metal dumpster full of water at Patrick AFB. It sat outside for at
least six months before they auctioned off the entire load to a scrap metal
dealer. I went over to his place a few days later and bought the 9825 for
$3 for the plastic parts. It had been dropped and the case was split open.
It had been hit with something that ripped half the keys off of it and it
had been out in the weather and sitting partially submerged in water for at
least six months. I poured the water out of it, brought it home and dried
it out. I was just going to use if for mechanical parts but I decided to
try it out just for kicks. Imagine my surprise when it worked! I've
probably found 30 or more surplus 9825s over the years and I don't think I
ever found one that didn't work.
Joe
At 09:19 PM 5/4/04 -0700, Michael Holley wrote:
That's
what you'd think but it isn't the case. 9825s in paricular are
nearly indestrucable but I have constant problems with all of the 9845s.
In 1979 I did a data-logging project at the Hanford Nuclear Reservation in
central Washington. We had 6 or 7 trailers that collected ground water
measurement on HP 9825s (using the built in tape drive.) The measurement
equipment was connected via HP-IB.
The power was from a mobile generator. Every time the air conditioner
started the line voltage would dip about 25 volts.
This test ran for over a year with out a single failure. I was impressed.
In the spring of 1980 the place was thick with grasshoppers. They would get
into the equipment it you let them. After Mount St. Helens dumped a foot of
ash on the place there wasn't a grasshopper to be found.
Michael Holley
www.swtpc.com/mholley
4:21 a.m.
The instrument reliability was similar...
One of the standard tests at the HP Colorado Springs
Divisions (I assume it similar elsewhere in HP) was to
put the equipment in a test chamber and run it at
50 deg C 90% humidity for a couple of days.
While testing the 1631 the test tech accidentally set
the temp way high with the 90% humidity and left for
the weekend... There were two test run units in the
chamber, and on both units the tops of all the
electrolytics on the PS were cupped due to the heat,
as well as visible melting on some of the other
plastic parts (the plastic nosecone was obviously
stressed...)
We took the two units and (for the fun of it) applied
power. One powered up, and could run measurements. The
other worked OK once we had replaced the power supply with
one from the line. Of course, their testing days were
done and we replaced them with two new line units, but
after replacing the second power supply and some of the
cosmetic parts, they ended up as lab instruments on a bench...
Pretty impressive, along with the other testing --
the shaker table (it would shake all the keys
off the 64000s during test -- keys all over the test
chamber...), 10' drop test, days of temp cycle testing
between the instrument limits, and electrostatic testing
(one of the test guys would wander around with a 10K
test wand and zap everything in sight...)
When I worked in displays, every so often someone would
get the cables in the casters of their chair and scoot
across the cube to grab the phone, and drag a display
off the bench (or a scope, etc.)
Seen most units survive this _special_ environmental
test...
Bill
BTW: Regarding the thread about the 6809 processor, the 1630/1631
used the 6809 as the main processor. 1611/1615 used an 8080, and
the 1610 used a 6800. 165x/16500 used a 68000. IIRC the 1640 serial
analyzer used a 8080...
Joe R. wrote:
My favorite story is about the badly beat up 9825
that I found in a
large metal dumpster full of water at Patrick AFB. It sat outside for at
...snip...snip...snip...
Joe
At 09:19 PM 5/4/04 -0700, Michael Holley wrote:
>>That's what you'd think but it isn't the case. 9825s in paricular are
>>nearly indestrucable but I have constant problems with all of the 9845s.
>
>In 1979 I did a data-logging project at the Hanford Nuclear Reservation in
...snip...snip...snip...
>Michael Holley
>www.swtpc.com/mholley
11:39 a.m.
try it out just for kicks. Imagine my surprise when it
worked! I've
probably found 30 or more surplus 9825s over the years and I don't think I
ever found one that didn't work.
The 9825 (and for that matter the 9815 which has much the same design of
PSU) does have one problem, though. The 5V PSU is a switching regulator,
and there's no corwbar fitted (no idea why not, the older 9810 and 9830
have crowbars on all the important PSU outputs, so HP certainly knew about
such things). If the chopper transistor shorts, then 5V line will leap to
about 25V. Needless to say this wipes out the entire set of ICs... The
9845, with a mains-input SMPSU (not the low-voltage non-isolated switching
regulator of the 9815 and 9825) doesn't suffer from this.
I must design a crowbar and add it to my machines sometime. Hopefully
before the transistor fails.
-tony
7537
days inactive
7538
days old
3 comments
4 participants
participants (4)
-
ard＠p850ug1.demon.co.uk -
bill_mcdermith＠mcdermith.net -
rigdonj＠cfl.rr.com -
swtpc6800＠comcast.net