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New piece for repairing HP41c broken lower posts
07-19-2021, 10:30 PM (This post was last modified: 07-19-2021 10:43 PM by Divasson.)
Post: #3
RE: New piece for repairing HP41c broken lower posts
(continued from previous)

The new piece is self-centering: it should enter in the holes and stay placed. (The old piece was only glued to the surface, and needed to be centered on the holes with small screwdrivers or other method. This was critical for a good assembly later)

• When applying pressure, use clothes' pegs to hold the piece in place, preferably on the outer side.

• To avoid pushing the keyboard down, and only push down the front of the calculator, use the keyboard cover we have designed to support the pegs. Pushing the keyboard instead will result on separation between both halves of the calculator, since the attachment of the substrate to the pin will be at a lower level (the keyboard is linked to the keyboard circuit, not to the substrate). Alternatively, you can use a couple of credit cards which will avoid the clothes’ pressing the keys all the time.

• Use E6000 glue. Make sure that there is no solvent or circuit cleaning residue – it will disable the gluing effect of E6000
• Let it cure overnight.
• Remove the tape over the zebra circuit trace: in particular what affect the circuit traces.
• Place the zebra connectors
• Put the processor circuit, Assemble the calculator and test. The screws (more so if they lar of the long variety) press the "claws" of the piece outward and make an even better connection between piece and keyboard circuit.

We recommend repairing both posts at the same time. However, if you are confident on the resistance of the other post, you can cut the piece in two. As it is symmetrical, it can be used for both posts, just twisting it 180º.
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RE: New piece for repairing HP41c broken lower posts - Divasson - 07-19-2021 10:30 PM

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