HP 11C

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HP 11C
PredecessorHP 33, HP 34C
Entry modeRPN
Display typeSegmented LCD
ProcessorHP 1LE3, 1LF5, 1LM2, 1LQ9
Power supply3x SR44/LR44/AG13

The HP 11C is a midrange scientific calculator from the HP Voyager series.

Features[edit | edit source]

Introduced in 1981, the HP 11C was the first HP Voyager model released to the market. The HP 11C is placed between the HP 10C and HP 15C in terms of features offered.[1] Consequently, a large portion of the units manufactured use the earliest Voyager internal designs, as after the introduction of the HP 15C in 1982 popularity of the 11C fell sharply.[2]

Programming[edit | edit source]

Common issues and repair[edit | edit source]

Hardware revisions[edit | edit source]

The earliest 11C revisions used two separate PCBs, one with the logic and display, and a second with the keypad. Later revisions consolidated everything down to one board further reducing cost.

Electrostatic discharge (ESD) protection was a major consideration in the design of early voyager models, as time went on the methods of ESD protection on the 11C changed. Early models had minimal protection, one spring to connect the front and back metal plates, and conductive textured rubber feet connected to the rear metal plate with a copper tab. Later models switched to two springs and omitted the copper tab and conductive feet, while adding additional plastic sheets on the rear of the button PCB.

Date code Battery contact type Processor PCBs ESD shielding Springs Grounded feet
2127 Metal tab 1LE3 2 Minimal 1 Yes
2137 Metal tab 1LE3 2 Large plastic flaps 1 No

See also[edit | edit source]

References[edit | edit source]