SCL Unicorn Microcomputer

[BBC Micros ]     [Computers ]

Introduction

Unitl 2008 I had never heard of the SCL Unicorn Microcomputer, but with a bit of research using Google I found that SCL (Semi-conductor Compex Ltd), an Indian goverment enterprise, had built BBC Microcomputers under the name SCL Unicorn Microcomputer in 1985/6. I assume this was under license from Acorn. I don't know how many were produced or when production ceased.
 
If you have more information about the SCL Unicon Microcomputer, please contact me.

Manuals and documents

In November 1984 Acorn User published a news item titled "India takes on Beeb assembly ".

SCL Unicorn Microcomputer

When I got this BBC Microcomputer I assumed that it was an Issue 2 model based on the design of the black panels and the cut outs at the back. But when I opended the case I found the circuit board says SCL Unicorn Microcomputer rather than Acorn Computers Ltd. I am not sure if this is a genuine SCL Unicorn Microcomputer or an SCL Unicorn Microcomputer circuit board in an Acorn Issue 2 case.
 
Here are some pictures:

SCL Unicorn Microcomputer (front) 

It looks kike a BBC Micro Issue 2 or 3 with "BBC Microcomputer" and the Owl on the right of the keystrip. Note that a LED has been added later on the left, I think that this is a disc activity light.

 SCL Unicorn Microcomputer (back)

This looks like a BBC Microcomputer Issue 2 or 3 with the reset label and cut out and 2 line copyright meesage. The power supply is an Astec mdel as used on all later BBC micros.

 SCL Unicron Microcomputer (bottom)

This looks like a BBC Microcomputer Issue 2, there is no white rectangle for the serial number (which is unfortunately missing), There are "Fix" labels next to the screws that hold the top of the case on and the power output details are missing from underneath the power out label

SCL Unicorn Microcomputer with the top cover removed. 

This looks like a early BBC Microcomputer keyboard with no grill over the speaker.

SCL Microcomputer with keyboard removed 

 SCL Unicorn circuit board

This looks like a BBC Microcomputer Issue 7 circuit board with a "small" heat sink on the ULA . It has the Econet and Intel 8271 Disc interfaces installed.

Here is a Hi-res picture of the SCL Unicorn circuit board .

Close up of the SCL Unicorn Microcomputer label and serial number 

This picture shows the SCL Unicorn Microcomputer Label. The serial number is 0007502. Note also the SCL India 6522 on the right and the 8540 manufacture data on the Texas Intrument Speech chip.

 Close up of the SCL India 6502 and 6522 ICs

Close up of the Sideways ROM sockets 

This shows the sideways ROMs which are, from left to right, OS 1.20, BASIC 2, and DNFS 3.0

 Close up of the SCL Unicorn Video out UHF out

This shows the composite video out has been replace with a plug connector and the unbranded UHF modulator.

 Close up of the SCL Unicorn RAM

This shows that the RAM chips are ceramic Intel D2118-3 instead of the plastic 4816 usually used in BBC Micros.

This computer is a bit of a contradiction with features from both early and later BBC Microcomputers. This may be because that's the way that SCL made it, or it may be becasue an SCL Unicorn circuit board has been used to update an early BBC Microcomputer.

Specification: