BBC Master Computers

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Introduction

The BBC Master was launched in January 1986. It was a major improvement on the BBC Micro, but was evolutionary rather than revolutionary. It had:

• More memory (128K like the BBC B+128K),
• Improved OS (MOS 3.20 replacing OS1.20),
• Improved BASIC (BASIC IV replacing BASIC II),
• View, ViewSheet, Edit and Terminal in ROM as standard,
• Cartridge slots, like the Electron Plus 1, that worked,
• Internal Co-processors (4MHz 65C02, 8MHz 80186)
• ADFS as standard, like the Electron Plus 3, as well as 1700 DFS
• Econet on a daughterboard module (no more solder jobs)
• Numeric keypad

At the same time the Master preserved compatibility with the BBC Micro. It had the same hardware interfaces so that most BBC peripherals would work with the Master. The OS had the same software interfaces so that much of the BBC Micro software would work. Where BBC software was not compatible the changes required were often minor. In other cases software changes were desirable to take advantage of the new features. All told this was the pinnacle of 8 bit development at Acorn and rivaled or bettered any other company's 8 bit computers.

When the Master Series was launched, Acorn advertised 4 computers, Master 128, Master Turbo, Master 512 and Master Scientific. The Master Turbo has a 65C12 co-prosseor. The Master 512 had an Intel 80186 co-processor. The Master Scientific had a National Semiconductor 32016 co-processor, however I have never seen a Master Scientific and it does not appear in Acorn price lists for 1986, 1987 or 1988. I suspect it was never sold, although a Master 128 with an external 32016 second processor might qualify.

Manuals and Documentation

 Here are two Acorn brochure with an overview of the Master series of computers:
 

In March 1986 Acorn User published a review titled 'Master Work'.
In March 1986 Personal Computer World published a review titled "BBC Master 128 ".

Here is the Acorn Master Series Hardware Specification (Feb 86),  which includes The Master 128 Repair Guide, the 65C102 co-processor user guide and Fitting an ECONET module.

The Master Welcome Guide is the user guide for the BBC Master, I have not scanned it as it is too long. Copies appear on ebay from time to time. Alternatively a scanned copy can be downloaded from the 8bit software  site

The Master Reference Manual (parts 1 & 2) gives more detailed technical information. I have not scanned them as they are too long. Copies appear on ebay from time to time. Alternatively scanned copies can be downloaded from the 8bit software  site

There was an issue about replacing the battery that backed up the CMOS RAM, Acorn produced a leaflet explaining how to replace it:
Master Series Battery Unit Issue 1 Jan 87
Master Series battery Unit Issue 3 May 93 

Master Computers

Acorn released the following Master models:

• AMB15 - Master 128
• ADB12 - Master Econet Terminal
• ADB20 - Master Compact 

which were sold as the following computers:

• Master 128 
• Master ET
• Master Turbo
• Master 512 
• Master Compact 

In addition to the Acorn computers there are some companies that used the Master motherboard in their own computers:

• LTM Portable