Don Foreman wrote:
I like Hewlett Packard calculators. I have two HP32SII's and a 42S,
have worn out several others over the years since the HP-35, the
first scientific handheld calculator with trig functions and all. I
felt lucky as hell to find one of those used at $135, in the early
'70s when that was more than a house payment. That's when I retired
my trusty Post Versalog slide rule. I also have an HP48G but I've
never liked it much. Too damned complicated for everyday use.

One 32SII has been my shop/lab workhorse for over a decade. The
buttons are still legible, all but one anyway. Lately some of the
buttons got to be intermittent. Got out the "backup" 32SII I
spotted (and glommed) in a bookshop years ago after HP had quit
making them. There were none to be had here but this bookshop was
on a back street in Ghent, Belgium.

Same keyboard problem with it, though it has about no "miles" on it.
Oh, darn! Got out the 42S which I'd been hoarding because I
*really* like that calculator. Same thing. Ooooooo nooooooo!

Battery voltages all looked fine. I put new batteries in one anyway.
No help.

Then I recalled that one of my fishing sonars got wierd earlier this
year after a 1-week fishin' trip where it rained nearly every day.
One might think that a boat gadget would be weatherproof, right?
Maybe it was when new 6 years ago.

I'd bagged the sonar with a 1-oz desiccant pack for a few days. That
fixed it, as expected.

Mmmm (you can see it coming already, right?) I bagged the
calculators in a ziplock with a desiccant pack. Three days later,
they all work perfectly.

I'm gonna start using the 42S now. It's in brand-new condition but
it probably won't be for long, with everyday use in the shop/lab. What
the hell, I'm gonna enjoy it while I can still see it.

Hey, use it Don. If you don't your heirs will.....

At my age I don't even risk buying gren bananas anymore.


The 32SII's will be transferred to a screw-top jar with a coupla
desiccant paks.

My HP20 is still working OK.

But, serendipidously just last Thursday I thought I was making more
typos that usual on my computer at work, and when I went back to key in
a missed "W" I found the "W" key was almost non-functional, and would
only work if it was pressed down firmly while being pushed leftwards.

Now, I know a keyboard is only a $10 commodity, and I probably have at
least four old ones squirreled away at home (If I can remember where.)
But, there were none handy at the office. SWMBO was still writing a
report there and wasn't ready to go home yet, so I figured I'd use the
time have a go at cleaning up that keyboard.

After removing more screws than most XXX movies have I lifted the bottom
off the keyboard. I peeled the flex circuit up and used Q-Tips and
denatured alcohol to swab the little conductive rubber contact pads in
the hundred or so separate elastomeric contact cups, which looked for
all the world like AAAAAAAAA cup boobs lifted from a troop of Barbie
dolls. I wiped off the contacts on the flex circuit too.

After reassembly, like the Brits say, "Bob's your uncle!" The damn thing
worked like new. It's nice when things work out right the first time
once in a while, isn't it?

Over the years I've had many keypads where you push directly on the
rubber "keys" go flakey on me. Those keypads are usually found on things
like TV remotes and cheap calculators. When I open them up I often find
a green "slime" on the conductive rubber contacts on the underside of
the keys and on the printed circuit contacts which they close against.

When I clean that gunk off with denatured alcohol and put things back
together they always work fine again.

An Aussie phone technician told me that years ago a series of touch tone
phones down under used those "rubber keys" and that they caused the
phone company lots of problems. He said they tracked it down to "skin
oil" transfered to the tops of the keys migrating through the soft
rubber and ending up on the surface of the contacts. He said it happened
more on phones located in kitchens than elsewhere. More grease in the
air there I suppose.

Interesting....And believable to me as I've noticed when cleaning
keypads on TV remotes that the gunk seems worse on the frequently used
contacts than on the seldom used ones.

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."