Opening HP 33E

[TorstenHamburg]

Hello from Hamburg, Germany
I just tried to open my HP33E. After loosening the two screws in the battery compartment, I can open the case just 20mm. I am afraid to pull with more force....
What is the best way to open the case without destroying it.

Many thanks
Torsten

[teenix]

There are some notes about this in my Classic Notes PDF

HP used a tool as mentioned in the 33E service manual here.

cheers

Tony

[Massimo Gnerucci]

Another approach.

Then there's the famous waxed dental floss technique. ;)

[AndiGer]

Keep the 20mm open and press with your middle fingers inside the opened battery compartment and the thumbs on the bottom end as hard as you can ... maybe some wiggling of the back of the case needed as well.
It will come open with a crack sound.
Be careful not to break the battery contacts when opening at the top end as the contacts sometimes hook on the back when lifting it open.

[vaklaff]

I used the technique AndiGer mentions several times without a problem. Here it's in details and pictures.

Coincidentally, used it just yesterday again to open my misbehaving 34c, just to do a bit of cleaning. Didn't help unfortunately :-( Anyway, opening the case went fine.

[rprosperi]

The first time you open a spice this way is somewhat terrifying, the loud crack convinces you that you've pushed/pulled too hard, but the many times I've done it, everything is just fine. When you get it apart, it's easy to see why it makes that cracking sound, no doubt a choice made by some packaging engineers in the late 70's thinking "... yeah, this will be tremendous fun, we'll scare the hell out of owners taking these apart for decades...". Sadistic....

[BillBee]

That "crack" = what did I just break.

Try the floss method first. Sometimes the wiggle and pull can crack the front edge if a bit too aggressive.

-Bill

[TorstenHamburg]

Case is open and in goog condition. Thank you all.
Torsten

[vaklaff]

(08-15-2022 02:05 PM)TorstenHamburg Wrote:  Case is open and in goog condition. Thank you all.
Torsten

Good. What procedure did you use and how did it go?

[TorstenHamburg]

Hello vaklaff

I used the "dental floss" method. But the floss yarn I used was not strong enough. It broke. So I took a yarn that is meant for tying cables. It is about 2 mm wide and 0.8 mm thick and very, very durable.

Regards
Torsten

[BillBee]

I remember the first time I opened one up and took the board out. Not being careful I bumped the top half and had to play 30 key pick-up. It was fun trying to put them all back in the perspective spot. Those little buggers scattered when they hit the hardwood floor.

-Bill

[vaklaff]

(08-17-2022 04:53 PM)TorstenHamburg Wrote:  I used the "dental floss" method. But the floss yarn I used was not strong enough. It broke. So I took a yarn that is meant for tying cables. It is about 2 mm wide and 0.8 mm thick and very, very durable.

Thanks for sharing, Torsten, I'm sure your answer will help someone one day! IIRC my first attempt was the same as yours, then not having a more suitable yarn at hand I tried the "brute force" method. It worked fine so I'm sticking with it :-)

These hard-to-open cases drive me crazy. I am the exact opposite of handy and even trivial mechanical fixes are on the brink of impossible for me. Detailed procedures created by experts and follow-up success stories like yours give me - and maybe others like me - the necessary courage. I managed to open and fix a Spice and a Pioneer (thanks to Logan West). What's ahead of me is a 28s, I have one with bad keyboard contacts but Geoff Quickfall's description scares the hell out of me...

[dmh]

Has anyone tried to fabricate the tool mentioned above in the service manual?

It's hard to see exactly what it looks like but maybe someone has seen one and this is probably the best option (if it can be easily made).

I'm too scared to try the brute force method.

I tried and failed at the floss method.

The thumb pressure and wiggle a bit worked for me but I haven't been able to get them all apart this way - poor grip or worried about too much force.

(08-18-2022 05:08 AM)vaklaff Wrote:  

(08-17-2022 04:53 PM)TorstenHamburg Wrote:  I used the "dental floss" method. But the floss yarn I used was not strong enough. It broke. So I took a yarn that is meant for tying cables. It is about 2 mm wide and 0.8 mm thick and very, very durable.

Thanks for sharing, Torsten, I'm sure your answer will help someone one day! IIRC my first attempt was the same as yours, then not having a more suitable yarn at hand I tried the "brute force" method. It worked fine so I'm sticking with it :-)

These hard-to-open cases drive me crazy. I am the exact opposite of handy and even trivial mechanical fixes are on the brink of impossible for me. Detailed procedures created by experts and follow-up success stories like yours give me - and maybe others like me - the necessary courage. I managed to open and fix a Spice and a Pioneer (thanks to Logan West). What's ahead of me is a 28s, I have one with bad keyboard contacts but Geoff Quickfall's description scares the hell out of me...

[teenix]

The tool looks like it is made out of perspex from the service manual picture, probably just bent in a V shape.

I'm not sure if I would "rap" the calculator down on the bench to open it. Maybe back in the day when the plastic is not degraded as it might be now. Some of the plastic clips that hold the circuit boards in place seem to break easily, so something else may break with a hard knock on a solid surface.

cheers

Tony