HP33E repair

[Krauts In Space]

Some time ago I fished a HP33E in the bay. It was just to play with, so I didn't pay much attention on the condition.
Now as the batt pack passed by (not original, just two wire-soldered NiMH), I want to open and clean it as the power pins are "shiny blue" .
I also like to see for any more corrosion.
Here's the problem: I cant remove the lower shell. The opposite end to the screws seems fixed. Are there any hidden screws I missed? If not I must suppose a previous owner glued it, maybe because some nozzles are broken.
The net provides not much information on the 33E.

Best wishes,
KiS

[Massimo Gnerucci]

(01-07-2018 10:23 AM)Krauts In Space Wrote:  Some time ago I fished a HP33E in the bay. It was just to play with, so I didn't pay much attention on the condition.
Now as the batt pack passed by (not original, just two wire-soldered NiMH), I want to open and clean it as the power pins are "shiny blue" :).
I also like to see for any more corrosion.
Here's the problem: I cant remove the lower shell. The opposite end to the screws seems fixed. Are there any hidden screws I missed? If not I must suppose a previous owner glued it, maybe because some nozzles are broken.
The net provides not much information on the 33E.

Best wishes,
KiS

Start here for pointers on how to open it.

And here, and here...

And then, one day, we will have a nice book from Geoff... :)

[AndiGer]

The second link Massimo gave is the best.
Pressing with thumbs - sometimes with all your force - will do the trick.
I managed to open all spices this way.
Andi

[Krauts In Space]

(01-07-2018 05:48 PM)AndiGer Wrote:  The second link Massimo gave is the best.
Pressing with thumbs - sometimes with all your force - will do the trick.
I managed to open all spices this way.
Andi

Thanks for advice.
The 2nd link helped me - nearly a physiotherapist grip
Great view inside. When was the last time I saw one of these 40 leged bugs? *g*

Thanks,
KiS

PS: what sort of plastics are the Spices/is the HP33 made of? The thread consoles fell off, the bottom shell is broken above one screw, and one nozzle of the battery cover is broken (... counting if all puzzle pieces are complete ...).

PPS: between keys and PCB there's some sort of yellow fabric. If I know what it is I maybe replace it by a new one. It's fairly in good shape, but like a 'good' service station I'd precautionary replace all parts possible

[jebem]

(01-08-2018 07:32 AM)Krauts In Space Wrote:  what sort of plastics are the Spices/is the HP33 made of? The thread consoles fell off, the bottom shell is broken above one screw, and one nozzle of the battery cover is broken (... counting if all puzzle pieces are complete ...).

The plastics can easily break around the posts where the two self tapping screws are inserted. This looks to happen on some of the HP older models, most probably caused by the aging plastics. We can see the same issue with other brands as well.
I don't know what type of plastics were used, but my understanding is that plastics are metastable and some types can be disturbed by small temperature and pressure variations along its aging process.
So I would like to learn on what type of plastics HP did chose for these machines as well.

(01-08-2018 07:32 AM)Krauts In Space Wrote:  PPS: between keys and PCB there's some sort of yellow fabric. If I know what it is I maybe replace it by a new one. It's fairly in good shape, but like a 'good' service station I'd precautionary replace all parts possible

My calculator do not use that yellow layer. Is that a foam?
Probably installed to stop the keys to jingle around.

I understand there are at least two different variants of these machines, where some use solder-less technology where the IC chips are just doing contact with the PCA by means of pressure (like mine here) and others uses a more traditional soldered chips.
Is yours using solder-less chips?

[Krauts In Space]

(01-08-2018 02:06 PM)jebem Wrote:  My calculator do not use that yellow layer. Is that a foam?
Probably installed to stop the keys to jingle around.

I understand there are at least two different variants of these machines, where some use solder-less technology where the IC chips are just doing contact with the PCA by means of pressure (like mine here) and others uses a more traditional soldered chips.
Is yours using solder-less chips?

All chips seem soldered.
And yes, the fabric seems to be some sort of foam.
Mine has 4 pins that lead through the fabric, keeping it in place.
To me it prevents that jingling and it covers/protects the electrics.
Not much improved since the 1980s to modern low profile keyboards

Solderles electronics? No corrodings?
Sounds not very reliable to me, but over decades working calculators prove me wrong ^^