Busicomputers Prophet 3       Credits to Chris
De Acorn Atoms van Chris Acorn computers site (at-http://acorn.chriswhy.co.uk/)

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Introduction

The Busicomputers Prophet 3 is a modified Atom built by Acorn for Busicomputers Ltd

Manuals and documents

I have no documentation for the Prophet 3.

Busicomputers Prophet 3

You will see the differences between the Atom and the Prophet 3 in the pictures. The Prophet 3 is similar to the Prophet 2 but has a built in disc drive. This Prophet 3 comes in an unlabeled metal case which houses the disc drive and power supply, I don't know if this was the original design or added later. The case has a handle for carrying which would make it a very early luggable, needing only a power supply and monitor.
 
Here are some pictures of the Prophet 3:

The Prophet 3 and TV, unfortunately it does not work yet.

 The Prophet 3 plugged into to my TV and swtitched on. Unfortunately it doesn't quite work correctly. I think the screen pattern may be a memory check failing. Below the TV is the Prophet 3 in its case. With the front flap down, you can see the floppydisc drive on the right with a disc in it (the disc is labelled "Prophet Plan").

Prophet 3 case (front)

 My Prophet 3 is in a steel case, I don't know if this was standard. The 2 clips at the top corners release the front flap to get to the computer. At the back on the right is the power out socket and video out socket for a monitor ,

Prophet 3 case right side

 My Prophet 3 comes in a case and on the right is the carrying handle. You can also see the clip in the top left to release the front flap and the monitor power out and video out on the top right (so you could place the monitor on top of the case).

Prophet 3 case back

 The back of the Prophet 3 case showing, from left to right:

• The on/off switch
• The power in socket
• Heat sink
• Slot for print cable.

On the top left of the case is the moniter power out and video out sockets.

Prophet 3 case top

 The Prophet 3 case top showing the monitor power out and video out sockets. At the bottom of the picture you can see the front flap and the tabs on the left and right to open it.

Prophet 3 case open

The Prophet 3 case with the front flap open, showing the Prophet 3 computer and the floppy disc drive above it. The floppy disc drive is a Y E Data YD580 5.25" 360KB drive.

Prophet 3 front and keyboard

The Prophet 3 pulled part way out of its case showing the disc drive on the right. The keyboard is the same as the Prophet 2, but there is no MODE switch on the top right, although the case has a cut out for it which is covered by the keyboard surround.

Prophet 3 out of case

 The Prophet 3 removed from its case showing, from left to right:

•  The video cable which connects to the socket on top of the case,
• The power cable from the built in power supply and which connects to the Prophet 3's power in socket. There is a hand written note on the bottom of the case "converted to 5V I/P".
• The ribbon cable from the Floppy Disc Controller to the disc drive.

Prophet 3 (top)

Prophet 3 (back)

 The back of the Prophet 3 showing, from left to right:

•  The Acorn Expansion Bus with the cable going back inside the computer,
• The printer port,
• The 5V DC Power in socket,
• The cassette port,
• The TV out port,
• The video out port

Prophet 3 open

 The Prophet 3, with the case open, showing:

•  At the top, the Atom motherboard,
• The red and black cable between the 2 halves is the Video out,
• The wide ribbon cable is plugged into the Atom Expansion Bus on the top half and the expansion cards in the bottom,
• The green expansion card is an Acorn 32K dynamic RAM card,
• Underneath the ribbon cable is the Floppy Disc Controller.

 Prophet 3 expansion cards

The two expansion cards fitted to my Prophet 3 are:

1. Acorn 32K dynamic RAM
2. Polebrook Computer Services Ltd FDC1   (floppy disc controller).

The cards are firmly stuck to the base of the Prophet 3 and cannot easily be removed.

Prophet 3 motherboard

The Prophet 3 motherboard showing, from left to right:

•  The left hand ROM with a white label is the P3 DOS ROM
• The right hand ROM with a white label is the P2/FP ROM
• On the left the graphics RAM is fully expanded
• On the right the text RAM is unexpanded
• The red and black cable at the bottom is the video out.

Here is a Hi-Res picture of the Prophet 3 motherboard. 

Prophet 3 keyboard

 Here is a Hi-Res picture of the Prophet 3 keyboard .

 Specificiation: