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The ATOM PROPHET and Hobbit

Another Atom was a model called the PROPHET supplied with a video connection at the rear and a mode switch on the right top from the keyboard. Many people thought it was great to get an Atom with red keys. This MODE switch was used to switch ROMs at #A000. The Prophet was initially sold as business computer with a B/W Television set, a micro cassette recorder in a robust metal case. (1983)
The computer could be used as a straight forward Acorn Atom in addition to its spreadsheet function by flicking a switch.

Prophet 1

the Prophet


video connection

mode switch

Keys are differently organized from both the standard Atom and the Prophet 2. The OS rom of the Prophet 2 is a standard one, as in standard mode (mode switch up), the keys behave as on an Atom, arrow down gives a beep, and it starts with the message 'ACORN ATOM'. With the MODE switch down, the machine also prints 'ACORN ATOM', but then gives an error message if no extension board on socket IC20, and hangs.

Prophet 2

The Prophet 2 had an 32 K dynamic RAM card fiited on the PL6/7 bus and the Calc rom on the main board..

dynamic RAM card

dynamic RAM

board + Calc ROM

Calc (IC20) PCB

Prophet 3

There's another Prophet variant, the Prophet-3 which has a built in disk interface, a Polebrook Computer Services floppy disc controller card using an Intel 8271 controller chip, power supply and diskdrive in a 'plinth' type contraption. The Acorn dynamic 32K ram card and the FDC were both connected to the pl6/7 bus

Prophet 3

on top bay + drive

Disk controller card

board + DOS ROM

FDC card, RAM card

At last the Prophet 3 had a DOS. The tedious cassette filing system on 300 Baud was replaced with a floppy drive. Also the cabinet was adjusted to a new smaller form.

Thanks to acorn.chriswhy.co.uk


The Hobbit Atom mentioned below has some interesting extensions on board. A graphic SRAM modification a 16 K SRAM card and a switching card model 1. The program memory is still present. The 16K SRAM is obviously used as an memory extension card. Both cards are connected to the PL6/7 bus.

Atom type Hobbit
Atom Hobbit

Recently I found an Atom Hobbit computer. Early in the seventies a Dutch magazine "The Hobbit" launched a home brew computer called the Hobbit. See the item Atom kit in the main menu.

Interior Hobbit Atom

SRAM video modification

Switch card on PL6/7

SRAM card on PL6/7

Expanded Atom cabinet

Another complete different Atom setup, is shown below. To make room for the extensions the original Atom cabinet was provided with a plastic frame glued on the bottom side from the original cabinet.

Keyboard + display

inside view

On the main board are on the extension bus PL6/7 the switching card and below from that the 16K memory extension card situated. On the right side is the C-MOS video card replacing the original 2114 IC's.

inside view profile
open zijkant
top view
switching card