First check the vac system filter has is OK if in eny doubt replace it.
If this has no efect on the AI or the vac px then the AI probably needs replacing , money spent on the new filter is not wasted as it will help protect the new AI.
A good place to get the parts is Airpart Supply at booker 01494 450366 but you MUST have the part number if they are to help you.
The AI will have the number on a data plate on the case.
[This message has been edited by A and C (edited 03 December 2000).]