For almost fifty years the Avometer has built for itself an unrivalled reputation for reliability and service. It is, however, inevitable that instruments fail from time to time, mainly due to accidental misuse, and when they do, it is essential that they are repaired to the highest possible standard. This booklet has been produced therefore to aid our customers and associates, both at home and overseas, and it is hoped that it will form a useful guide to the trained engineer who has the task of servicing our products. The instrument has not been dealt with in absolute detail, for to do so, would be beyond the scope of this publication, although it is assumed that the engineer undertaking the work has a good knowledge of the principles of moving coil multi-range measuring instruments and electronics. The instrument has been f broken down1 in such a manner that an engineer with suitable tools and test gear, can take Avo components and spare parts and fit them into the instrument, which will then only require a minimum degree of calibration and test. Particular note should be taken of the advice which is given regarding the use of complete sub-assemblies. It is advisable to keep a number of key items in stock, in order that they can be immediately available when required. A faulty movement can be returned to the factory and an allowance will be made for serviceable component parts. No attempt should be made to service an Avometer unless the full range of recommended test equipment, is available. In the event of a major overhaul the instrument should be returned to the Avo representative in your territory.