HP-11C semi-dead or what ?


first of all: I can't accept the fact that a HP-Calculator doesn't work
because of bad material, which fades away, or because of low accuracy
in the manufacturing.

It all began with a HP-11C ( USA 2552A03475 )I bought some weeks ago. It passes all
standard tests. All was very well. Then some day I want to have
fun with my little toy and played around. Hmm, what to do ? Another
key-board-test, but what's that, the display is frozen. Have I
pressed a wrong key or what ? panic....but remember old 41C...
get off the batteries...wait some seconds...and start again.
NOTHING....Hmmm....get off batteries put 11c on the shelf some
days....put in batteries...start....NOTHING...pressing randomly
some keys...oops, he is alive, works some seconds, but then gets
frozen again or doesn't start if turned off....same procedure many times. The machine doesn't
work reliable, but the core seems OK. I suppose it is in a special
state, some circuit/IC is in a wrong branch or something like that. Mechanical all seems OK.

I read some articles about dead 11C in this forum. Yes, I shortcut
the battery-contacts...WITH < shudder > and without batteries. Maybe now the
machine is really dead ;-)

Is there anyone out there, who can help me ?

Thank You.........Erich Neubacher



I had an HP12C in hands with a problem about the same; the difference is that it froze for good.

After resodering all of the IC's terminals, it became the same, good little girl "she" was. If you want to do so, say, to open the calcualtor and solder the ternminals, have a look here.


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