Q. Quite recently my one-year-old BBC micro, fitted with an Acorn DFS, has started to give the 'Acorn DFS' message a miss. If you turn the machine on and off several times you get the correct message. Please could you tell me what is wrong and what I should do about it.

Niall Habba
Prestel 01-997 7557

A. Since the DFS chip is a sideways ROM, it will have been placed in one of the sideways ROM sockets. These sockets are not of the highest quality and the ROMs have a tendency to come loose.

The best thing to do to cure your problem is to remove the top of the BBC and then the keyboard to gain access to the ROMs. Push all the ROMs in solidly and then switch the machine back on. If the 'Acorn DFS' note still does not appear telephone the nearest Acorn dealer and ask his advice, and if necessary get the machine serviced.

The message not appearing problem is caused by the ROM not being recognised by the Operating System, i.e. either the ROM is bust or not connected properly. The latter is the more likely cause and making sure that the ROMs are in properly is best fix.