Our FM4 full service includes: •Fault diagnosis.•Replacement of out of tolerance (OT) components.•Full RF, IF and stereo decoder alignment check & adjustment as required. The display brightness can also be improved to suit your taste, especially if it has started to dim over time. We also carry out any sensible modification if necessary to improve performance Many FM4s we receive in for service have a leaking 4.5V battery. We replace the battery and fit it in a shroud. This reduces the risk of circuit damage due to chemical leakage. Alternatively, for an additional cost, we can fit the Quad FM4 battery eliminator modification (shown ABOVE right) .