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.