Hewlett Packard HP-21

Serial Number 1508S26367: 1975, 8th week, Singapore (bought 31.7.1975)
Accessories Pouch

Power supply (switchable 110/220V, part no. 82024A)

Manual: HP-21 Bedienungs-Handbuch (German)

Battery holder for rechargeable or regular AA batteries

Manual: HP-21 Owner's Manual, July 1975, bound printout from the MoHPC CD-ROM
Condition Excellent!
Repairs 14.10.2002 Swapped the display with the HP-22 one. Now one of the segments is broken in the HP-21.
26.2.2003 Got another HP-25C and removed its display module. Now the HP-21 is fully functional again.
12.3.2003 Cut off the connector from the power supply and attached a small headphone plug so that it can be used with a regular off-the-shelf DC power supply.
Acquired 22.6.2002
HP codename/series Pumpkin, Woodstock
Type, Precision, Input mode Scientific, 10 BCD digits, exponent 99, Reverse Polish Notation
Programmable No
Memory Only one storage register for STO & RCL. No permanent memory.
Display 11 digit 7 segment red LED plus sign
Special features Warning: When operating with the power supply a rechargeable battery must be inserted!
Original Pricing, Production 1.2.1975 ($125) - 1.5.1978 ($80)
Batteries Battery pack equipped with 2x AA cells or power supply
Dimensions Length 12.7cm, Width 6.5cm, Height 2.9cm
Links HP-21 Owner's Manual, July 1975 (PDF) 
Quick Reference (PDF)
Comment HP's seventh calculator and first Woodstock model. Extremely simple, a real beginners model. However, the Woodstocks have their own charme in that they're very small and leightweight. Their shape is unrivalled and perfectly fits the palm of a hand.
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