HP-34C external battery charging

[Steve Simpkin]

(12-08-2017 11:23 PM)Craig Bladow Wrote:  ...
That reminds me that I need to weigh it to see if it is the soldered or press fit version.

With the batteries installed the original press-fit version weighs about 220-230 g. The newer soldered version is lighter and weighs around 170-180 g.

Another member writes the following:
"Pick one key (calculator ON or OFF), perhaps [ENTER] key and slowly press it till it "clicks" and stops. If the key's upper face (not the top of the key) hides itself in a way the top face almost reaches the keyboard level, then it is a solderless unit. If the key moves just a little bit and the upper face keeps half of it hidden and half appearing, then it is a soldered unit. This is because the solderless units have a single flex circuit that "plays the role" of keyboard contacts, circuit trails and IC's connectors, and the bubble caps for each key are somehow "far" from the keys contacts. The soldered units use metal caps almost like the ones used in the HP41 (and HP75C/D and HP71B) for each key, and their "moving range" is a lot smaller."