Hewlett Packard HP-31E

Serial Number 1924S33659: 1979, 24th week, Singapore
Accessories Pouch

Manual: HP-31E Owner's Handbook (not perfect condition, had been folded up)

Power supply

Rechargeable battery pack
Condition Excellent. Minor marks and scratches on the front plate. 
There also is a minor contact problem somewhere.
Repairs 3.7.2002 Disassembled the calculator but could not find anything regarding the contact problem. It must be somewhere in the power traces rather than the display because when power comes back the register contents are all gone.
Acquired 26.6.2002
Accessory Power supply, output 9V AC, 0.9W
Acquired 23.6.2002
HP codename, series Ginger, Spice
Type, Precision, Input Mode Scientific, 10 BCD digits, exponent ±99, Reverse Polish Notation
Programmable No
Memory No permanent memory. 4 variable storage places (RCL/STO 0...3).
Display 10 digit 7 segment red LED plus sign
Special features Warning: Do not operate unit with the AC adapter and no battery pack installed!! It does work somewhat but the calculator really behaves strangely!!
Original Pricing, Production 1.5.1978 ($60) - 1.2.1980 ($50)
Batteries Battery pack with 2x AA sized cells or power supply
Dimensions Length 14.1cm, Width 7.5cm, Height 2.9cm
Links HP-31E Owner's Handbook, January 1978 (PDF)
Comment A beginner's model. Many useful functions but the Spice design can by far not rival the Woodstocks! Also, these models have a few inherent flaws: The battery contacts tend to corrode and break off, the top corners of the plastic display cover easily break off.
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