The Museum of HP Calculators

HP Forum Archive 13

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Are older 12c's as high quality as 15c's?
Message #1 Posted by Josh P on 23 Nov 2003, 6:16 p.m.

HP Museum describes the 10c’s construction as follows: “Previous HP's had a flexible sheet under the keyboard to protect the electronics from minor spills and dirt. The 10C series took this further by having a single large sheet of film under the keyboard that wrapped around the electronics and overlapped at the back. This sheet consisted of three bonded layers: the outer layers were nonconductive, but the center layer was conductive. There was also an inner conductive film surrounding the main circuit board. These films gave the CMOSC chips a high degree of electrostatic protection.”

Were the 12c’s made during the same time period (‘80's) put together as well as the other Voyagers? Maybe the engineering Voyager's were designed to survive harsher conditions than those used by the business folks?

Edited: 23 Nov 2003, 7:38 p.m.

Re: Are older 12c's as high quality as 15c's?
Message #2 Posted by Nelson M. Sicuro (Brazil) on 23 Nov 2003, 8:46 p.m.,
in response to message #1 by Josh P

I have a HP-12C with the flexible circuit board and a protective "envelope" around all circuit. Is very well made, build in 1983 in USA. I had a identically well made HP-15C made in Brazil back in 1983 (bought new, sold in 1989 to buy a 42S). These old ones have in the battery compartment two single foiled springs.

The newer HP-15C and 11C that I have doesn't have the protective "envelope", and the circuit board is rigid with the chips, display and keyboard alltogether. These newer ones have in the battery compartment a helical spring in one side and a golden squared contact in the another side.

The HP-12C suffered several other modifications, that I don't know yet.

In short, the first "Voyagers" are all the same quality. The entire line followed the same modifications (I heard that the 12C ones where the first to be "upgraded") until they take the 10C, 11C, 15C out of busines... :(

Anyone to confirm this?

Best regards,


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