Reparing a HP18



Can anyone assist me with instructions on how to open a HP18C.

Any help would be greatly appreciated.


Kevin Johnson


Opening a 18 or 28, is for all practical purposes, a non-reversible procedure. Kinda like a calculator
post mortem.

If you want to have a look-see and assuming you are working on the right side:

Peel off the 18C label at the top. Peel off the label surrounding the keyboard. Most likely, several small plastic rivet heads will fall out. The ones that don't fall out, drill out by hand by rotating an appropriately sized twist drill until the head of the plastic stake releases. Once they've all been removed, the case halves will separate.

There is no good way other than gluing to reassemble. Some have mentioned small screws or bolts to hold the halves together. The glue method is obviously a one-time deal and if the pins below the LCD are broken, there is little point for reassembly.

Good luck.


The 18C is still fairly easy to find and reasonalble, even on ebay. Buy a another one. This calculator often sells for under $40 in good shape (I bought one for about $20 in new cond about 2 years ago this way). This is probably because it is Algebraic only, and doesn't have any scientific functions or as much RAM as the 19B series that replaced it shortly after its release.

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