HP 48SX does not switch on

[Marck]

Hi all,

I pulled out of the box after many years my HP 48SX which is in perfect
conditions...except for the fact that it doesn't switch on!
Of course I put 3 new batteries in it.. but nothing happens. Does
anybody know if I can perform some little tests to try to understand
what's happening and fix the problem?

Many thanks to all of you.
Marck

[Han]

On Jan 21, 10:23 am, Marck <marck-DO-NOT-USE-T...@microsoft.com>
wrote:

Underneath one of the four rubber feet is a reset hole that you can
try. READ YOUR MANUAL FIRST as the hole is not in the same place for
all ROM versions.

[Marck]

On 21/01/2010 18:52, Han wrote:

> Underneath one of the four rubber feet is a reset hole that you can
> try. READ YOUR MANUAL FIRST as the hole is not in the same place for
> all ROM versions.

thanks a lot, there's a hole underneath each of the 4 rubber feet and
the manual doesn't tell everything about a reset button... i tried to
"press" in every hole but I didn't feel anything like a button "click"
inside, only a hard surface...

I tried the reset memory command described in the manual (ON+A+F buttons
pressed together) and also tried to change the AAA batteries with new
ones but still nothing seems to happen, the screen is always off.. :-(

Any more suggestions?
Marck

[Yann]

Looks electrical.

Maybe you can't avoid opening your HP48sx case (follow instructions to
do it without damage)
you may end up discovering a simple connection issue between battery
lanes and the board to power.

[John H Meyers]

On Thu, 21 Jan 2010 13:57:18 -0600, Marck wrote:

> there's a hole underneath each of the 4 rubber feet and
> the manual doesn't tell everything about a reset button..

> i tried to "press" in every hole but I didn't feel anything
> like a button "click" inside, only a hard surface...

There is nothing so fancy as a "button" in the HP48[S/G] series;
the "reset switch" contact in my 48G is made between a bent piece
of thin shielding and the circuit board, when a paper clip
pushes part of the shielding towards the circuit board,
and then hits the board.

Best to use as thick a paper clip as can fit into the hole.

Postings about resetting a 48S[X] (or sometimes 48G[X]):

http://groups.google.com/group/comp.sys.hp48/msg/d3c69db4f936720c

http://groups.google.com/group/comp.sys.hp48/browse_thread/thread/e14d7ca65ac5a58

By Dave Arnett (HP electrical engineer on HP48 series):
http://groups.google.com/group/comp.sys.hp48/browse_thread/thread/c294d11b77c5b804
DO NOT REVERSE THE BATTERIES (that was NOT Dave speaking!)

--

[John H Meyers]

Turn on an AM radio and hold the calculator next to it.

If it's on and running but the screen is blank,
you will still hear ample radio noise,
at which point one could try increasing the contrast (ON and + ?)

I suppose it might even be worth checking very carefully
to see that the batteries are all facing in the correct directions
(the middle one is opposite to the others, right?),
that the contacts or batteries themselves are not corroded,
and that despite being "new," they all also really deliver
the required output (try the set of three in some
high-powered flashlight which happens also to use 3xAAA)

Press down between screen and top row of keys while pressing ON,
as sometimes there are internally failing connections around there.

That "pressing down" reminds me of pressing down on a crown...

"Mr. Carlisle said in 1878 that this was a struggle
between the idle holders of idle capital and the struggling masses
who produce the wealth and pay the taxes of the country;
and my friends, it is simply a question that we shall decide
upon which side shall the Democratic Party fight.
Upon the side of the idle holders of idle capital,
or upon the side of the struggling masses?"
[William Jennings Bryan, July 9, 1896]
http://historymatters.gmu.edu/d/5354/

"You shall not press down upon the brow of labor this crown of thorns.
You shall not crucify mankind upon a cross of gold."

Bryan lost the 1896 U.S. Presidential election to William McKinley;
McKinley was re-elected in 1900, then shot to death in 1901...
http://www.whitehouse.gov/about/presidents/williammckinley

...which elevated Theodore Roosevelt to the Presidency.
Roosevelt received a Nobel Peace Prize, was later shot, but recovered.
http://www.whitehouse.gov/about/presidents/theodoreroosevelt

Whatever happened to those formerly regulated huge corporations,
once actually discouraged by Republican leaders from becoming overly powerful?
As of today, they can spend unlimited sums on political campaigns,

Has anything ever changed? Perhaps the climate.

Has your HP48SX switched on yet? Maybe it doesn't want to bother.

[r->] [OFF]

[Marck]

On 22/01/2010 0:36, John H Meyers wrote:

> Press down between screen and top row of keys while pressing ON,
> as sometimes there are internally failing connections around there.

You are the man! :-)
That was the problem... I pressed down in that zone and now it switches on!!
I was able to reset it (the reset "button" is where the "R" letter is
under the topright foot), to clear the memory and now it seems to
work... but I need to press down in that zone at almost every key
pressure in order for it to work, also to switch it on and off, and
while pressing the two "shift" keys (blue and orange one)

First of all I want to thank everybody who answered here to my request,
then I want to add another request:

is there a way to fix this need to press between the screen and the top
row of buttons? should I open it?

Many many thanks to all of you again!
Marck

[John H Meyers]

On Fri, 22 Jan 2010 02:45:22 -0600:

> is there a way to fix this need to press between the screen

> and the top row of buttons? Should I open it?

Personally, I stopped opening things when manufacturers
started making things designed to require breaking to disassemble.

If mine happens to exhibit this problem, next time I exhume it
from wherever it is buried, I might look for a strong plastic
"wire/cable tie" of the type which can be pulled very tight and sort of
"locks" as one tightens it, to "cinch" around the body at the right point,
perhaps with some small pad under it to press on the needed area.

Clear shrinkable tubing might also work, and also be less ugly,
if one can find some. I've neither tried nor read of anyone doing this,
but thought experiments performed on someone else's calculator
are risk free to me :)

[r->] [OFF]

[Han]

http://www.math.uiuc.edu/~handuong/hp48/open
http://www.math.uiuc.edu/~handuong/hp48/repair

[Yann]

Pretty cool tutorial, Han.

[trywait4]

I have the same '48SX No Turn On' issue.
None of the prescribed techniques work for me. (Though I had a flakey 32-S that did become reliable again with the Short Batty Terminals, but I got that off the FAIL 8 code site.)

I am ready to pop the top on the 48SX, Someone mentioned Instructions?
Anyone have a clue? I am motivated to get this big guy working again, along with myself!

Thanks, Someone Special

[gkar...@gmail.com]

THANKS AGAIN

[severin....@gmail.com]

press the area under the display and press on at the same time. that did it for me.

[Jack]

My HP48GX is doing the same thing. The manual offers several ON + (different keys) but none work. It had been working perfectly and then I laid it aside for about a week. I have done cleanup in the battery compartment. Is there a place to send it for repair. Is there a place to buy a graphical & programmable scientific HP calculator?

[John Finley]

Just a note of confirmation: I pulled my dad's 48SX out of storage, put new batteries in, and could not get it to turn on with the reset (under top right foot), with ON/+, ON with any top row keys, reversing batteries briefly, holding reset a long time... what worked is pressing between display and top row of keys while I press ON. It turns on, but many key presses don't work unless I'm also pressing below the display (e.g. I can enter numbers and press ENTER, but none of +/-/x// work unless I press up there, then can't turn it back on.

I get an audible "click" when I press there, like there's something sticky, some goo. I might open it up, but just knowing what ails it might be enough for now (15C works the day job).