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LTM Portable

[Master Computers]     [Companies  ]


The LTM Portable is a "luggable" BBC Master (it weighs 17.5kg). It has a standard Master Issue 2 motherboard with an internal 6502 Co-processor . It is packaged with a green screen monitor and 2 x 5.25" floppy disc drives in a large, heavy case. It does not include batteries and runs on mains power. From the paper label on the back it appear that the computer was used by the Radio Investigation Service HQ.

The only reference to it that I have found is in the 8-Bit Software  web site which has a similar computer and a second one based on a BBC Model B+.

Manuals & documentation


LTM Portable

I bought my LTM portable on ebay in 2008 (they are fairly rare).
Here are some photographs:

LTM Portable

  LTM Portable

  The LTM Portable plugged in, switched on, and running Acorn MOS 3.20 ( the standard Master OS).

LTM Portable top

LTM Portable (top)

The LTM Portable is big, approximately 590 x 510 x 190 mm, and weighs 17.5kg. [Measured from bottom of the feet to top of the handle and from the widest bit where the handle is.

LTM Portable front

 LTM Portable (front)

The front of the LTM portable with the keyboard up. There are 2 buttons at the top of the case which release the keyboard. Note also how the handle becomes a support to hold the LTM portable at a suitable angle. There are 3 possible positions.

LTM Portable left

 LTMP Portable (left)

The button which releases the keyboard is visible at the top of the keyboard and the button which releases the handle is visible in the middle of the joint.

LTM Portable back

 LTM Portable (back)

The back of the LTM portable shows the Master ports in the central top cutout, they are, from top left to bottom right:

To the left of the cuttout, the pair of switches to sellect 40/80 track mode for the 2 floppy drives, the single switch switches the monitor on/off (it is disconnected inside). The power in and On/Off switch are on the right.

The paper label on the back says:

LTM Portable right

 LTM Portable (right) with keyboard down

LTM Portable with keyboard down

 LTM Portable with keyboard down

The keyboard is a standard Master keyboard.

LTM Portable open

 LTM Portable with the top cover removed

Removing the top cover of the LTM Portable shows:

Note how the ribbon cables from the Tube, 1MHz Bus, User, printer and floppy disc drive ports are all lead neatly away under the motherboard. The keyboard connectors are led forwards to the keyboard.

LTM Portable Master motherboard

 LTM Portable Master motherboard and the 6502 co-processor

LTM portable motherboard without 6502 Co-Pro

 LTM Portable Master motherboard without 6502 co-processor

Here is a HiRes picture of the Master Motherboard. 

LTM Portable bottom open

 LTM Portable with bottom cover removed

With the LTM's bottom cover removed shows from top left:


ModelPMS 040/RF
Serial No.1075
Motherboard Serial No.01-ADT01-10001157
Mortherboard0243,000 Issue 2
CPU Clock2MHz
Disc ControllerVL1772-02PC
Disc Filing SystemADFS 1.50
DFS 2.24
OSOS 3.20
Add-in/Upgrades6502 co-processor