Replacement battery pack for BBC Master 128
This is a replacement battery for the BBC Master 128 computer.
If your BBC Master is not saving it’s settings the chances are the battery pack needs to be replaced.
This replacement uses a long life lithium battery (3.6V) pack which replaces the original BBC Master battery. The long life batteries normally last around 5-8 years.
The replacement battery pack is fitted with a diode and a current limiting resistor to prevent the BBC from trying to charge the battery (The original BBC battery was rechargeable which is why you cannot just replace the batteries with alkaline non-rechargeable ones)
The battery pack includes battery and battery holder and is fitted with double sided self-adhesive tape to allow you to fasten it to the inside of your case.
Fitting Instructions:
Remove the cover of your BBC Master and locate the old battery pack on the left. Unplug and remove the old battery and make sure the battery connector pins on the motherboard are not corroded.
Remove the self adhesive tape on the new battery and fit it in a suitable position. Connect the battery to the 3 pin socket (PL8) on the motherboard. The connector can go either way around as the middle pin in positive. Make sure the connector is correctly plugged in and not offset.
To reset your CMOS, power up your BBC Master while holding down the R key. After a few seconds you should see “CMOS RAM reset”
The battery received may be from a different manufacturer but will be functionally identical.
Only the battery/battery holder is included in the sale. The BBC Master shown in the photo is not included and for illustration only.
Battery is new and has been tested in my BBC Master 128
