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checking why old HP48S does not turn on anymore
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marcomaggi
Dec 17, 2011, 2:32:24 PM12/17/11
to
Ciao,
I have an old HP48S I would like to resurrect for a young relative
in need of his first scientific calculator. Unfortunately the machine
does not turn on anymore, there is nothing at all on the screen; is
there something I can do to check if it is truly gone?
I have left the machine without batteries for years, but, as far as
I remember, when I stopped using it it was working perfectly. I have
double checked to have correctly inserted the new set of batteries and
measuring the voltage across the machine's terminals gives me some
fine 5 V; trying with ON and + and ON and C nothing happens; looking
in the batteries chamber, everything looks clean.
I would like to open it to peer inside for dust and leakage from old
batteries, but it appears to be very difficult to open without
breaking it.
TIA
--
Marco Maggi
I have an old HP48S I would like to resurrect for a young relative
in need of his first scientific calculator. Unfortunately the machine
does not turn on anymore, there is nothing at all on the screen; is
there something I can do to check if it is truly gone?
I have left the machine without batteries for years, but, as far as
I remember, when I stopped using it it was working perfectly. I have
double checked to have correctly inserted the new set of batteries and
measuring the voltage across the machine's terminals gives me some
fine 5 V; trying with ON and + and ON and C nothing happens; looking
in the batteries chamber, everything looks clean.
I would like to open it to peer inside for dust and leakage from old
batteries, but it appears to be very difficult to open without
breaking it.
TIA
--
Marco Maggi
Raymond Del Tondo
Dec 17, 2011, 4:22:35 PM12/17/11
to
Ciao,
it's perfectly possible that the contact stripe between the
LCD and the keyboard pcb has shrunken over the years.
Does the machine return an error beep
if you press the divide key ?
As for opening, here's a very nice documentation:
http://users.ju.edu/hduong/open/
For more HP related info, there are some docs and links
available on www.hpmuseum.org
HTH
Ray
"marcomaggi" <mrc...@gmail.com> schrieb im Newsbeitrag
news:b69977b1-5579-4b6b...@32g2000yqp.googlegroups.com...
it's perfectly possible that the contact stripe between the
LCD and the keyboard pcb has shrunken over the years.
Does the machine return an error beep
if you press the divide key ?
As for opening, here's a very nice documentation:
http://users.ju.edu/hduong/open/
For more HP related info, there are some docs and links
available on www.hpmuseum.org
HTH
Ray
"marcomaggi" <mrc...@gmail.com> schrieb im Newsbeitrag
news:b69977b1-5579-4b6b...@32g2000yqp.googlegroups.com...
marcomaggi
Dec 18, 2011, 7:03:26 AM12/18/11
to
On Dec 17, 10:22 pm, "Raymond Del Tondo" <Ih8...@nowhere.invalid>
wrote:
Thanks. This is a Singapore unit; I am fighting with it...
--
Marco Maggi
wrote:
> Does the machine return an error beep
> if you press the divide key ?
I can hear nothing. But is the default for BEEP set to true?
> if you press the divide key ?
Thanks. This is a Singapore unit; I am fighting with it...
--
Marco Maggi
marcomaggi
Dec 18, 2011, 7:46:54 AM12/18/11
to
On Dec 18, 1:03 pm, marcomaggi <mrc....@gmail.com> wrote:
> This is a Singapore unit; I am fighting with it...
There open. And it does look neither dirty nor fried, AFAICT.
> This is a Singapore unit; I am fighting with it...
--
Marco Maggi
Nicola Bressanin
Dec 18, 2011, 11:52:04 AM12/18/11
to
Check the welds:if in doubt re-heat them with a small electronic
soldiering iron
soldiering iron
Georg Bisseling
Dec 18, 2011, 12:00:03 PM12/18/11
to
Did you try to reset it with a bent paperclip?
At least the 48GX had a little whole hidden under oone of the rubber feet
for that purpose.
--
Erstellt mit Operas revolutionärem E-Mail-Modul: http://www.opera.com/mail/
At least the 48GX had a little whole hidden under oone of the rubber feet
for that purpose.
Erstellt mit Operas revolutionärem E-Mail-Modul: http://www.opera.com/mail/
marcomaggi
Dec 18, 2011, 2:56:29 PM12/18/11
to
On Dec 18, 6:00 pm, "Georg Bisseling" <ge...@bisseling.de> wrote:
> Did you try to reset it with a bent paperclip?
>
> At least the 48GX had a little whole hidden under oone of the rubber feet
> for that purpose.
>
AFAICT there is no such thing on the 48S. The rubber feet are
> Did you try to reset it with a bent paperclip?
>
> At least the 48GX had a little whole hidden under oone of the rubber feet
> for that purpose.
>
inserted in the lower half of the case, which is connected to no
electronics; everything is attached to the upper half.
--
Marco Maggi
marcomaggi
Dec 18, 2011, 3:03:21 PM12/18/11
to
On Dec 18, 5:52 pm, Nicola Bressanin <nicola.bressa...@gmail.com>
wrote:
accessible side. It is safe to detach the upper half of the case from
the board?
--
Marco Maggi
wrote:
> Check the welds:if in doubt re-heat them with a small electronic
> soldiering iron
Mh, there are not many that I can touch in this way, at least on the
> soldiering iron
accessible side. It is safe to detach the upper half of the case from
the board?
--
Marco Maggi
Raymond Del Tondo
Dec 18, 2011, 3:29:05 PM12/18/11
to
The S Series has the hole under the same rubber foot as the G Series.
If you look at the back side, battery door facing down,
it's the upper right rubber foot, under which you'll find a small hole,
and left to the hole a very small letter R (for Reset) .
news:a089c78c-8db1-411d...@z1g2000vbx.googlegroups.com...
If you look at the back side, battery door facing down,
it's the upper right rubber foot, under which you'll find a small hole,
and left to the hole a very small letter R (for Reset) .
news:a089c78c-8db1-411d...@z1g2000vbx.googlegroups.com...
marcomaggi
Dec 18, 2011, 4:56:01 PM12/18/11
to
On Dec 18, 9:29 pm, "Raymond Del Tondo" <Ih8...@nowhere.invalid>
wrote:
specially cut piece of the metal sheet attached to the lower half of
the case, and this piece should touch something on the board causing
it to go at the minus of the batteries.
Anyway, I have reassembled the unit and inserted the batteries and
while I was trying to finish closing the case the machine turned on I
was able to execute some command. Then I tried to turn it off, but it
did not accept the command: all the buttons on the lower line seemed
to work but the ON one. Then I tried again to fully close the case
and the machine turned off; and now I cannot turn it on again.
He! He! At least now I know that it is not fully broken.
It seems that some of the rivets at the corners of the metal sheet
to which the board is attached got out of place while I forced the
case open. I will try to put them back in position tomorrow, with
friendly sunlight.
Thanks for the help so far!!!
--
Marco Maggi
wrote:
> The S Series has the hole under the same rubber foot as the G Series.
> If you look at the back side, battery door facing down,
> it's the upper right rubber foot, under which you'll find a small hole,
> and left to the hole a very small letter R (for Reset) .
Yes, I see it: inserting a tiny something in the hole it bends a
> If you look at the back side, battery door facing down,
> it's the upper right rubber foot, under which you'll find a small hole,
> and left to the hole a very small letter R (for Reset) .
specially cut piece of the metal sheet attached to the lower half of
the case, and this piece should touch something on the board causing
it to go at the minus of the batteries.
Anyway, I have reassembled the unit and inserted the batteries and
while I was trying to finish closing the case the machine turned on I
was able to execute some command. Then I tried to turn it off, but it
did not accept the command: all the buttons on the lower line seemed
to work but the ON one. Then I tried again to fully close the case
and the machine turned off; and now I cannot turn it on again.
He! He! At least now I know that it is not fully broken.
It seems that some of the rivets at the corners of the metal sheet
to which the board is attached got out of place while I forced the
case open. I will try to put them back in position tomorrow, with
friendly sunlight.
Thanks for the help so far!!!
--
Marco Maggi
Virginie Marovics
Dec 24, 2011, 5:49:38 PM12/24/11
to
printed, and the circuit is 'faded' so wont work anymore. You have
like me a fully functional calculator with just one stupid key that
does not make contact anymore :(
I hate when thos stuff happen hundred dollars mott for a 10 cent sheet
of plastic you cannot change without breaking anything.
If only they provided spare parts....
Message has been deleted
Bart
Dec 26, 2011, 9:43:14 AM12/26/11
to
while you press a key. The rubber support that pushes the
keyboard contact strip gagainst the PCB, tends to deteriorate.
Here is a thread that discusses the problem:
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv019.cgi?read=151696
Also see:
http://users.ju.edu/hduong/open/
and
http://users.ju.edu/hduong/repair/
(on the last page see pictures labelled "HP48G Keyboard Connectors"
and "Rubber Under Keyboard Contacts" )
The solution is simple, replace the rubber sponge strip.
Regards
Bart
Marco Maggi
Dec 28, 2011, 7:22:37 AM12/28/11
to
On Dec 26, 3:43 pm, Bart <b...@barend.plus.com> wrote:
> Try pressing on the bezel, between the display and the soft keys,
> while you press a key. The rubber support that pushes the
> keyboard contact strip gagainst the PCB, tends to deteriorate.
Thanks for the very interesting links. I will try it.
> Try pressing on the bezel, between the display and the soft keys,
> while you press a key. The rubber support that pushes the
> keyboard contact strip gagainst the PCB, tends to deteriorate.
--
Marco Maggi
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