HP33E repair

[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?