HP 9830A

The Hewlett-Packard 9830A is a rather interesting desktop "calculator" from 1972 (it is actually a computer, but was marketed as a calculator to make it easier to buy for large companies that have been taken over by bureaucrats [buying a computer at that time was a big deal!]).

Its processor architecture is based on the 16-bit HP 2100-series minicomputers, but implemented in a bit-serial way (the processor's ALU only processes 1 bit at a time instead of 16, which makes it slower, but requires less transistors to implement and is therefore cheaper). The processor frequency is 8MHz. The machine runs a pretty featureful version of BASIC, which can be additionally expanded with plug-in ROM modules (to add e.g. matrix operations, plotter control, etc.).

The 9830A was usually paired with a 9866A thermal printer, which could only print characters (upper-case, 5x7 dot matrix, 80 characters per line), but at 250 lines per minute. You can use standard fax machine paper rolls in this printer.

The calculator itself weighs 20kg and the thermal printer 17kg. Not only is it built like a tank, it also weighs like one!

As for the power consumption, the calculator on its own uses about 90-105W when idling, the printer on its own 80-95W, and both together about 170-225W. The power factor is pretty decent for a linear power supply — a steady 0.76.

My HP 9830A has 7904 words of memory (maximum possible) and a 9866A thermal printer. It's still fully functional after more than 40 years! It also used to have a nice plotter (the ROM packs are still in the machine), but that was sadly scrapped by some heartless bastards before it came into my possession :(

If you have an HP 9862A plotter that you'd like to sell or donate, please contact me (my email address is in the page footer).

Pictures ^

HP 9830A with thermal printer
Close-up of the keyboard
Installed ROM packs
A top view of the boards inside
Linear power supply (09830-66551)
Standard memory board (09830-66584)
Memory expansion board (11275-66584)
BASIC ROM card 1 (09830-66521)
BASIC ROM card 2 (09830-66526)
Close-up of the ROM chips
Extension ROM selector (09830-66525)
Extender card for debugging
CPU control (09810-66513)
CPU data path (09810-66514)
CPU I/O interface (09810-66511)
CPU clock and I/O state machine (09810-66512)
M register (09830-66582)
T register (09830-66583)
Cassette tape interface (09830-66561)
Cassette tape control board (09865-66562)
Cassette tape read/write board (09865-66563)
Cassette tape motor control board (09865-66564)

Documents ^

Links ^


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