Introduction 5 Procedure for Ordering Spare Parts 5 TEST FACILITIES AND EQUIPMENT REQUIRED 1. Essential Test Facilities, Equipment and Conditions 6 Instrument and Test Gear 6 Tools and other Aids 7 Spare Parts 7 Miscellaneous Items 7 PRELIMINARY PROCEDURE 2. Suggested Repair Procedure 8 3. Consideration of the Customer's Report 8 4. Fault Diagnosis 9 5. Accuracy 9 6. Removal of the panel from the case 9 7. Removal of movement from panel 10 THE SUPPLY OF INTERCHANGEABLE PARTS AND SUB-ASSEMBLIES 8. Sub-Assemblies 10 9. The Bottom Resistance Board 11 10. The Top Resistance Board 11 11. The cut-out Mechanism 11 12. The Movement 12 FAULT-FINDING AND SERVICING INFORMATION 13. Fault-finding table 13 14. Servicing Information 14 DISMANTLING AND RE-SETTING INSTRUCTIONS FOR SWITCHES, CUT-OUT MECHANISM AND MOVEMENT 15. Main Switches 20 16. Leaf Switches 21 17. Cut-out Repair and Setting 22 18. Dismantling the Movement 23 FINAL PROCEDURE 19. The appearance of the repaired instrument 25 20. Flash Test 25