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Calculadora gráfica HP expandible basada en RPN. Fabricado desde 1990 hasta 2003.

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Are there any repair kits available? my keyboard doesn't work

Only the enter, 7, 4, 1 and zero keys work.

How do you open the case without destroying the case and/or looks?

Any common problems with the keyboard that I should look for?

Once I'm inside, are there any upgrades to do before I exit and put it back together?

I love this machine, it got me through engineering school and I really hate to abandon my "war buddy"

Any suggestions would be appreciated,



Contestado! Ver respuesta Yo también tengo este problema

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4 Respuestas

Solución Elegida

Here is a link to a series of doc files from HP on your calc. Hope it helps. Ralph

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Thank you for the links, lots of interesting information about my calculator.

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The problem lies with the ribbon cable between the keypad and display. It either works loose or corrodes slightly.

Non invasive solution:

Press the front hard between the 2 leftmost function keys at the top of the keypad while using the keypad. It's really awkward but it works.

Invasive solution:

This involves sliding a blunt flat tool (spatula?) into the side join of the case by feel and then using a thin knife to locate and cut the plastic pillars in the middle of the case. I am sorry this is not very detailed but I decided not to risk it myself and have since lost the link to the site that gave instructions.

I hope knowing it is out there will help you to search and find it.

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+ it's an old thread but looks interesting :-) anyhow, here are some more instructions for the dis-assembly

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This is an older article, but just to add my two cents if anyone comes by here later. This device is a giant pain. Even using my fancy toolkit from iFixit, I've been whipped.

Yes, there are plastic rivets inside that hold the two halves together. There are instructions I found on that indicate you can pop them apart and still reassemble with no issues. Well I got the two rivets at the top of the screen apart, but I wasn't able to get them snapped back together. The link at listed above say to pry off the metal label cover off so you can drill out the rivets and reassemble using machine screws, which sounded like an appealing option in case I needed to get in again. But all I succeeded in doing is warping the cover in multiple places from the spudger underneath the face plate because the glue is just too tight. I stopped before I had bumps all over the face of my calculator.

Nevertheless, this article did have a solution for me: just press the face of the calculator just below the screen and above the soft function buttons to re-establish any loose connections.

I'll go hang my head in shame in the Corner of Failure now.

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when you press, look on the side as the two halhs move closer together. add a drop of instant glue and together they stay...

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Wow, this is not a job for the faint of heart, and takes intermediate to advanced skills. I did this back in 1999 before there were iphones and kits to open and fix those. You may read some things like "butter knife" or "exacto blade" in this article and you may have better sputdgel tools of your own. Bottom line is that this is not easy.

I doubled the memory in my HP48G from the built in 32k RAM to 64K of RAM. This was after college because I was too scared to pry open my expensive calculator that I needed to pass my college EE classes. When opening it I scratched the PCB while breaking the plastic posts near the top of the screen, and the traces on the surface of the PCB were broken. I had to put "microwires" to bridge 3 of the traces to "fix" the calculator. I knew those lines had to do with the display because I powered it up and found that three of the scanlines to the display were not working. Thankfully the micro-wires fixed the issue, and I was able to reassemble the calculator and get it back to functional with 2x the memory.

The instructions for doubling the memory are not at the link below. What I recall was that I piggy backed a second 32K chip directly on top of the first one, all connections were identical except the highest memory address. I had to hook that one up with a wire to a different spot (Basically this added a bank of memory and used the existing additional memory address line on the PCB.

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