HP 48G not in use for some years and now it won't turn on

[noe12]

Hello,

I have an HP 48G that I had lend some years ago and just now they finally gave it back to me.

It turns out it hasn't been used for some years. I have just bought new batteries and put them on (it didn't have any) and it won't turn on. I saw in another post that I should try to charge it through USB or a mobile charger, but this model doesn't have an USB port or any port I can recognize. It only has a big one on top with four little spikes and I don't have nor know that adapter.

Can anyone help me out?

Thanks in advance!

Regards!

[Joe_Horn]

> I saw in another post that I should try to charge it through USB or a mobile charger...

That doesn't apply to the HP 48G, which is not rechargeable.  Even if you put rechargeable AAA's in it, plugging it into its special 4-pin cable won't recharge the batteries.  That cable is for HP-to-PC data transfer only; it does not power or recharge the calculator.  BTW, it's a serial RS-232 port, not USB, so don't attempt to connect USB or a power source to it!

If you already made sure that the 3 batteries are strong and are installed in the correct directions, then my guess is that your 48G is refusing to turn on due to one of three reasons: (1) a nasty crash, (2) short circuit in the keyboard cable, or (3) dead calculator.  Respective suggestions:

(1) Try pressing ON and C at the same time and then releasing them.  If that doesn't wake it up, try ON, A, and F at the same time.  If it asks "Try To Recover Memory?" press the NO key (F) and you're back in business (with your memory cleared).  But if neither of the above do anything, continue reading.

(2) The keyboard cable on the 48G is notorious for failing in its old age.  But applying a little pressure with a finger between the "B" key and the display (just press down on the metal bezel there) will often temporarily re-connect the short circuit.  If that's the problem, then you'll have to press there every time you use the ON key.  It's annoying but it works; my 1993 HP 48G (ROM version K) has been like this almost forever.

(3) If neither of the above help, then I suspect you have a dead calculator.  Hum "Taps" while placing it solemnly in the recycle bin. 😞

Disclaimer: I don't work for HP. I'm just another HP calculator fan.

[Maké]

Hi!, noe12:

Welcome, to Forum !.

1) Clean with pharmaceutical alcohol, each terminal's (+/-), where put battery.

2) With batteries installed, check if have continnuity between, first negative contact and four positive contact and too, verify if delivery tension (4.5DC).

3) I have one battery charger, connected with one jack, inserted in my HP48G+.

Note: See too, from ... http://support.hp.com/us-en/document/bpia5170

[BartdB]

Try a warmstart, that is hold down the ON key, press and release C, release ON.

If that doesn't work, try doing a restart with a paper-clip reset. Remove the upper right (as viewed from the back) rubber foot. You'll see a small hole with the letter R next to it. Gently insert a straightened paper-clip (or something similar) straight in as far as it will go, and release it.

If the above doesn't solve it, the problem may be more serious:


Try pressing on the bezel, between the display and the soft keys, while you press a key.

The problem then is that there is a rubber support inside pushing the keyboard connector flex onto the PCB, this rubber tends to deteriorate.

Here is a thread that discusses the problem:
http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv019.cgi?read=151696

If you have a wish to try to repair it:
here is a guide to opening:
http://users.ju.edu/hduong/open/

and for repairing:
http://users.ju.edu/hduong/repair/

(about halfway down see "keyboard connector" and "Rubber Under Keyboard Contacts" which is the bit that has to be replaced).

(Note: the SX shown in the links above is physically the same as the GX)

Someone's temporary fix without opening the calculator:
http://h30499.www3.hp.com/hpeb/attachments/hpeb/bsc-408/13673/1/HP42S.jpg

[BijanK]

Thank you very much for this helpful post! My 1990 HP48G was not in use for a decade with batteries inside. I cleaned out the contacts with vinegar and tried everything to revive it. What finally worked was pressing with my fingers between B and the Screen as was pointed out to bring back the contact to the keypad. I am very excited that the trusty old 48G is once more alive!

[noe12]

Hi Joe!!! Joe_Horn

This is a little late... a year and a half late. I just remembered this because I got an email about a new comment.

I tried all of the above at the time and the calculator just wouldn't start. I had given up on it but didn't throw it out as it also has sentimental value to me (yeah, I know, it's stupid, but well...). I ended up buying a crappy one in order to sit my Math and Statistics exam.

Today I got this emai of the new comment and I re-read your advise and I said "what the hell, let's try again". The first option didn't work. But then, I tried again the option where I had to press the space between "B" and the display. And guess what? IT TURNED ON.

But now the problem is that I get the message "Try to recover memory?" but when I try to press NO (F), nothing happens. I tried every button on the keyboard and nothing happens. I tried pressing again between B and the display and then retried every button but still, nothing happens.

What can be the issue now? Can the keyboard be damaged? But if it were, how was I able to turn it on in the first place? Should I hazard opening up the calculator to try and fix it? I'm afraid to do even more damage. I intend to take Financial Math next period and it would be great if I could use this one in stead of the crappy one I bought last year.

I'm sorry to be coming again with this after so much time.... but the good news is that at least it is not dead! 🙂

-Noelia.

(I'm sorry if I wasn't clear enough, English is not my first language. If something is not clear enough please let me know).

[Joe_Horn]

When the "Try To Recover Memory?" message appears, try pressing down on the display bezel as you did when turning the calculator on, and then (while still holding down the bezel) press the E key, release it, then press the F key.  The  release the bezel.

The reason for the seemingly unnecessary E key is that once in a while (unpredictably) the TTRM? prompt does not respond to the F key until any other key is pressed first.  This is true even in brand-new perfectly functioning HP 48G's.

In extreme cases of keyboard cable dysfunction, you might have to keep pressing down on the display bezel as you use the calculator.  Just don't press too hard, since that will make the dysfunction progressively get worse and worse until it no longer works at all.

If the above doesn't help, then your keyboard cable is probably too badly dysfunctional to allow calculator use.  Repairing the calculator is possible, but I've never done it myself so others will have to help you there.  The simplest solution is to buy a 48G that works.

[Maké]

Hi!, @noe12:

If you needed repair your HP48G, you can write in Spanish Language, by email, to ... http://www.deachp.com/soporte/

For added security, you can see, this link ... http://h30434.www3.hp.com/t5/Calculators/48G-repairs/td-p/5714697/highlight/true/page/3