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HP Forum Archive 02

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openning HP-33E
Message #1 Posted by Jerry Doctor on 13 Dec 1999, 8:54 p.m.

I have an HP-33E that is just about perfect except. . .

Operation of this machine is somewhat erratic. I thought the problem might be due to poor electrical contact between components and decided to try opening the case and see what there was to see. I removed the two screws in the battery compartment. There don't seem to be any at the other end. (I looked under the rubber feet.) I thought maybe it just hooks in some how and tried pulling it apart.

I lifted the back at the battery end until it was about 45 degrees to the rest of the case. Still didn't want to let go. Can anyone let me in on the secret to getting the back off?

Re: openning HP-33E
Message #2 Posted by Viktor Toth on 13 Dec 1999, 10:52 p.m.,
in response to message #1 by Jerry Doctor

Pry it a little beyond 45 degrees. You'll hear a loud SNAP and your heart will stop because not only is the noise really LOUD, you'll be convinced that you have just ruined your machine.

In fact, you'll just have managed to separate the top and the bottom halves.

Before you do this, make sure that the battery connector remains attached to the top half (i.e., when the halves separate, you don't rip out the flexible connector by mistake.)

Usual disclaimer... do this at your own risk. Worked for me, but that doesn't mean that it'll work for you.


Re: openning HP-33E
Message #3 Posted by Jan H. Bos on 14 Dec 1999, 8:04 a.m.,
in response to message #2 by Viktor Toth

Victor is right. The further stepps depend on the version you have. Some are put together by two metal clamp strips at each side. First you have to list both circuit boards out of the casing. They are hold by the black plastic clamps. If you have the circuit boards out, carefully remove the clams and the calc wil drop apart, even the chips wil fall out, notice their position and orientation! The display wil also drop out. When you reassemble be sure that the metal strips fit snugkly. You should push the pins of the display back in between the circuit boards with some resistance. If you accidentally break the flexible power line, this can be repaired as I have done already. Good luck and regards, Jan

Re: openning HP-33E
Message #4 Posted by Frank on 14 Dec 1999, 4:10 p.m.,
in response to message #3 by Jan H. Bos

For what it's worth, I tried a prybar on mine, but the case broke. I'll sell it on eBay for parts. Frank

Re: openning HP-33E
Message #5 Posted by orbital1 on 14 Dec 1999, 5:23 p.m.,
in response to message #1 by Jerry Doctor

i think the "real" way to open one of these involves removing the keypad overlay. this exposes openings over the tabs at the bottom, and a flat blade screw driver can be inserted to release them. i doubt you will find a new overlay, though, and it would be difficult to remove it without damage. other than that, just pull it apart. i've done a few that way, and none of them have broken (though they were probably close) but it does normally scar the plastic where the upper and lower cases meet.

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