25 Apr
2007
25 Apr
'07
12:27 a.m.
On Tue, 2007-04-24 at 21:24 +0100, Tony Duell wrote:
Oh, Bollocks... you're exactly right. Please retract my previous
retraction. <Grin>
I could have been in denial for a few years, I suppose... <Sad
smile>
I've
got an HP-150 which just developed a video problem. Any chance
the TechRef is downloadable somewhere?
I don;t think it is. The obvious place to look would be
http://www.hpmuseum.net/ . I think the service manual is there, but
that's a boardwsapper guide, no schematics. What's the problem with your unit? Does it appear
to be a digital
problem, or a problem with monitor circuit?
Digital, I suspect. Although, this is a rather bizarre problem, and
COULD be a video problem, I suppose. When I boot it up, it works
correctly, as far as I can tell, with the single exception that the
screen shows what it should be showing, only in reverse video, and
without the characters being visible, whatever the brightness level. In
other words, I see the PAM blocks where they should be, but reversed.
If I press the proper keys to run a DOS "Dir" command, I see it run
past, but only as an empty reverse-video field block. It previously
worked correctly, the only event transpiring between then and now being
a replacement of the "N" type batteries that keep the CMOS going.
know HP is
still here, but, ending somewhere in the 1990s, they lost
that "magic touch." Previously, EVERYTHING they did was close to
We've discussed this many times at HPCC meetings. My feeling is that the
'golden years' of HP were about 1965 to 1987. The real 'death' came when they split off the
test equipment division as
Agilent. At one time HP were known for making some of the best test gear
available [1], now they're known for cheap and nasty inkjet printers. A
great pity if you grew up with their great products.
Exactly.
[1] Although I always thought Tektronix made better
'scopes :-)
I think the Tek's may have been more fully-featured, but I liked the
HP 'scopes just fine. If you leave the two companies out of it, you've
cut off almost all the truly great 'scopes.
I have an _old_ -- over 40 eyars old -- HP frequncy
counter.
Sounds like you are discussing an HP 5245L...
Apart from
a very clever design (how about making a decade counter, latch and nixie
tube driver in 8 transistors (and no ICs), I am always amused by the fact
that the _low precision_ timebase is the intenral oven-stabilised crystal
oscillator, good to 3 parts in 10^9 after warmup and calibration. The
high precision add-on was, of course, a rubidium beam.
That's the HP I knew and loved :-)
Yes! Our lab had a cesium beam that we used as an external standard
for the 5245Ls. Truth be told, however, there really wasn't much
difference, especially if one "tuned up" the crystal oscillator by
beating it against the Cs beam frequency reference. We were ACCURATE.
I loved it.
Needless to say I am addicted to their (old)
calculators. I still
routinely use HP41s. There's an HP16C on my workbench. I regard the
HP9100 as the most elecgant piece of electronics that I've ever had the
pleasure to work on. THe HP98xx series (all of them -- 98x0 and 98x5
machines -- are interesting, ingenious, and still work well with minor
repairs30 years after them were made. And as I mentioend I like the
9000/200 series.
I recently bought an HP-85. Mistakenly, I thought it was a 9830.
Some friends and I almost managed to go in hock to buy one of those
(9830) beasties when they were new. It was SO cool. Probably a good
thing we didn't... Computing got VERY cheap VERY soon after that.
Anyway, thanks so much for your assistance.
Peace,
Warren E. Wolfe
wizard at voyager.net