No problem, the one you will want is a Scantronic 9427, that's if there is one around for you to find, not been made for years, ebay would be best bet. --- BUT
Why do you feel you need to change it?
From what you have said the problem seems to be a very faulty battery!!
18 years old, they should be replaced at a Max. of every 5 years so you should be on your 4th at least.
The battery will be in the large whiteish box that is the control panel, look in the loft/garage/under stair cupboard etc
I expect the battery you need will/should be a 12v 7Ah, Screwfix is a good place for these or even Maplin.
Post HERE again with further information, you never know we might be able to help some more.
acorn
June 2010
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