DATAMATH

DATAMATH CALCULATOR MUSEUM

Hewlett-Packard HP-65

Date of introduction:	January 19, 1974	Display technology:	LED
New price:	$795 (MSRP 1974)	Display size:	10 + 2
Size:	5.9" x 3.2" x 1.40" 151 x 81 x 36 mm³
Weight:	10.9 ounces, 308 grams	Serial No:	1333A23534
Batteries:	3*NiCd AA-size	Date of manufacture:	wk 33 year 1973
AC-Adapter:	HP-82002	Origin of manufacture:	USA
Precision:	10	Integrated circuits:	HP65-CPU, Mostek MK6111...MK6113
Memories:	9
Program steps:	100	Courtesy of:	Ken H. Meine

Hewlett-Packard introduced on January 19, 1974 with the HP-65 the World's first Pocket Programmable Calculator. A marvel of engineering at its time, the HP-65 accommodates in a housing only slightly larger than the legendary HP-35 a card reader for its tiny magnetic strips to archive programs. Users could store programs with up to 100 steps on the cards or buy pre-programmed cards from either Hewlett Packard or third party companies.

The HP-65 was replaced after 2 years with the HP-67 featuring 224 merged program steps and 26 memories instead of 100 partially merged program steps and 9 memories. Compare these specifications with both the Texas Instruments SR-56 and SR-52 programmable calculators.

The HP-65 uses the Reverse Polish Notation with the [ENTER] key instead the usual [=] key and takes the responsibility for:

• The Death of the Slide Rule
• The never ending Rivalry between TI and HP calculators users
• The cat and mouse game leading to products like the HP-67 or TI-59

Dismantling the featured HP-65 with Date code 1333A manufactured in August 1973 by Hewlett Packard in the United States reveals a very solid design centered around a Hewlett Packard proprietary CPU (Central Processing Unit) with multiple Integrated Circuits (ICs) mounted in a ceramic package and supported by three MK611X ROMs (Read-only Memories) with a capacity of 1,024*10 Bits, each and manufactured by US semiconductor company Mostek. Please notice the Date codes on these chips, they were manufactured between week 10 and week 32 in the year 1974 - an obvious sign for some update of the microprogramming of the HP-65.

Learn more about Mostek Calculator Integrated Circuits.

If you have additions to the above article please email: joerg@datamath.org.