BBC Master battery pack

Replacement CMOS battery pack for theBBC Master 128

from retroclinic.com (Mark Haysman)

price: 12 GBP platforms: BBC

A single Lithium Thyonyl Chloride 3.7V cell in a pack with diode and limiting resistor. Original batteries should be replaced if still fitted, this one can last up to 10 years.

The BBC Master contains a battery. Some still have their original cells. They can leak, mostly over the plastic casing, but if too severe, can lead onto the PCB, and cause serious damage to the internals of your Beeb.

When the machine is on, will attempt to charge any battery connected to it. For non-rechargable batteries, this is very bad, and can cause overheating, or worse. To counter this, any batteries used should be fitted with a diode and current limiting resistor to prevent back-charging.

Mark supplies two versions of his battery pack, one contains alkaline cells which require changing every 12 months. The pack featured here contains a single lithium cell that lasts much longer.

Find out more / buy at: http://www.retroclinic.com/acorn/mbattery/mbattery.htm